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Title: GENETIC SCREENS IDENTIFY NOVEL REGULATORS OF SLEEP AND METABOLISM IN DROSOPHILA MELANOGASTER.
Creator: Murakami, Kazuma N., Keene, Alex C., Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: Proper regulation of sleep and metabolism are critical to the survival of all organisms. In humans, dysregulation of sleep is linked to metabolic syndrome, including hypertension, hyperglycemia and hyperlipidemia. However, the mechanisms regulating interactions between sleep and metabolism are poorly understood. Although the fruit fly, Drosophila melanogaster, bears little anatomical resemblance to humans, it shares similar genetics essential in understanding normal development and disease in...
Show moreProper regulation of sleep and metabolism are critical to the survival of all organisms. In humans, dysregulation of sleep is linked to metabolic syndrome, including hypertension, hyperglycemia and hyperlipidemia. However, the mechanisms regulating interactions between sleep and metabolism are poorly understood. Although the fruit fly, Drosophila melanogaster, bears little anatomical resemblance to humans, it shares similar genetics essential in understanding normal development and disease in humans. From humans to flies, many disease-related genes and pathways are highly conserved, rendering the fruit fly ideal to understanding the interactions between sleep and metabolism. Therefore, using the fruit fly provides a framework for understanding how genes function between sleep and metabolism. During starvation, both humans and rats reduce their sleep. Similarly, previous studies have shown that fruit flies also suppress sleep to forage for food, further showing that sleep and metabolism are intricately tied to one another and that they are highly conserved across species. To further explore the interactions between sleep and metabolism, I have conducted multiple genetic screens to identify novel regulators of sleep-metabolism interactions. These experiments led to the identification of the mRNA binding protein translin (trsn) as being required for starvation-induced sleep suppression. A second screen that targeted metabolic genes from a genome-wide association study identified the ion channel accessory protein uncoordinated 79 (unc79) as a critical regulator of both sleep duration and starvation resistance. The genes function in different regions of the brain and suggest complex neural circuitry is likely to underlie regulation of sleep metabolism interactions. Taken together, a mechanistic understanding of how different genes function to regulate sleep in flies will further our understanding of how sleep and metabolism is regulated in humans.
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Date Issued: 2021
PURL: http://purl.flvc.org/fau/fd/FA00013722
Subject Headings: Drosophila melanogaster, Sleep, Genetic screening
Format: Document (PDF)

Title: Development of a novel assay for in vivo screening of neuromodulatory drugs and targeted disruption of cholinergic synaptic transmission in Drosophila melanogaster.
Creator: Mejia, Monica, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Finding novel compounds that affect neuronal or muscular function is of great interest, as they can serve as potential pharmacological agents for a variety of neurological disorders. For instance, conopeptides have been developed into powerful drugs like the painkiller PrialtTM. Most conopeptides, however, have yet to be characterized, revealing the need for a rapid and straightforward screening method. We have designed a novel bioassay, which allows for unbiased screening of biological...
Show moreFinding novel compounds that affect neuronal or muscular function is of great interest, as they can serve as potential pharmacological agents for a variety of neurological disorders. For instance, conopeptides have been developed into powerful drugs like the painkiller PrialtTM. Most conopeptides, however, have yet to be characterized, revealing the need for a rapid and straightforward screening method. We have designed a novel bioassay, which allows for unbiased screening of biological activity of compounds in vivo against numerous molecular targets on a wide variety of neurons and muscles in a rapid and straightforward manner. For this, we paired nanoinjection of compounds with electrophysiological recordings from the Giant Fiber System of Drosophila melanogaster, which mediates the escape response of the fly.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3362560
Subject Headings: Drosophila melanogaster, Genetics, Drosophila melanogaster, Life cycles, Insects, Physiology, Developmental neurobiology, Neural transmission, Cholinergic mechanisms
Format: Document (PDF)

Title: Characterization of Group B Sox genes in the development of Drosophila nervous system.
Creator: Singh, Shweta, Dawson-Scully, Ken, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Sox proteins all contain a single ~70 amino acid High Mobility Group (HMG) DNA-binding domain with strong homology to that of Sry, the mammalian testisdetermining factor. In Drosophila melanogaster, there are four closely related members of the B group, Dichaete (D), Sox Neuro (Sox N), Sox 21a, and Sox 21b that each exhibit ~90% sequence identity within the HMG domain.The previous study has shown that Dichaete plays a major role in embryonic nervous system development and is expressed in...
Show moreSox proteins all contain a single ~70 amino acid High Mobility Group (HMG) DNA-binding domain with strong homology to that of Sry, the mammalian testisdetermining factor. In Drosophila melanogaster, there are four closely related members of the B group, Dichaete (D), Sox Neuro (Sox N), Sox 21a, and Sox 21b that each exhibit ~90% sequence identity within the HMG domain.The previous study has shown that Dichaete plays a major role in embryonic nervous system development and is expressed in several clusters of neurons in the brain, including intermingled olfactory LNs and central-complex neurons strongly expressed in local interneuron of the olfactory system. However, little is known about the possible expression and functions of the related group B Sox genes in the larval and adult brain. In particular, it is unclear if Sox N may function along with Dichaete in controlling the development or physiology of the adult olfactory system. Our data suggests Sox N potential role in the elaboration of the olfactory circuit formation.
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004907, http://purl.flvc.org/fau/fd/FA00004907
Subject Headings: Drosophila melanogaster--Physiology., Transcription factors., Gene expression., Genetic transcription., Cell cycle., Neural stem cells.
Format: Document (PDF)

Title: Developmental delays in methionine sulfoxide reductase mutants in Drosophila Melanogaster.
Creator: Hausman, William, Binninger, David, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Aging is a biological process that has many detrimental effects due to the accumulation of oxidative damage to key biomolecules due to the action of free radicals. Methionine sulfoxide reductase (Msr) functions to repair oxidative damage to methionine residues. Msr comes in two forms, MsrA and MsrB, each form has been shown to reduce a specific enantiomer of bound and free oxidized methionine. Effects of Msr have yet to be studied in the major developmental stages of Drosophila melanogaster...
Show moreAging is a biological process that has many detrimental effects due to the accumulation of oxidative damage to key biomolecules due to the action of free radicals. Methionine sulfoxide reductase (Msr) functions to repair oxidative damage to methionine residues. Msr comes in two forms, MsrA and MsrB, each form has been shown to reduce a specific enantiomer of bound and free oxidized methionine. Effects of Msr have yet to be studied in the major developmental stages of Drosophila melanogaster despite the enzymes elevated expression during these stages. A developmental timeline was determined for MsrA mutant, MsrB mutant, and double null mutants against a wild type control. Results show that the Msr double mutant is delayed approximately 20 hours in the early/mid third instar stage while each of the single mutants showed no significant difference to the wild type. Data suggests that the reasoning of this phenomenon is due to an issue gaining mass.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004200, http://purl.flvc.org/fau/fd/FA00004200
Subject Headings: Aging -- Molecular aspects, Cellular signal transduction, Drosophila melanogaster -- Genetics, Mitochondrial pathology, Mutation (Biology), Oxidative stress
Format: Document (PDF)

Title: Synaptic Rearrangements and the Role of Netrin-Frazzled Signaling in Shaping the Drosophila Giant Fiber Circuit.
Creator: Lloyd, Brandon N., Murphey, Rodney K., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: In the developing CNS, presynaptic neurons often have exuberant overgrowth and form excess (and overlapping) postsynaptic connections. Importantly, these excess connections are refined during circuit maturation so that only the appropriate connections remain. This synaptic rearrangement phenomenon has been studied extensively in vertebrates but many of those models involve complex neuronal circuits with multiple presynaptic inputs and postsynaptic outputs. Using a simple escape circuit in...
Show moreIn the developing CNS, presynaptic neurons often have exuberant overgrowth and form excess (and overlapping) postsynaptic connections. Importantly, these excess connections are refined during circuit maturation so that only the appropriate connections remain. This synaptic rearrangement phenomenon has been studied extensively in vertebrates but many of those models involve complex neuronal circuits with multiple presynaptic inputs and postsynaptic outputs. Using a simple escape circuit in Drosophila melanogaster (the giant fiber circuit), we developed tools that enabled us to study the molecular development of this circuit; which consists of a bilaterally symmetrical pair of presynaptic interneurons and postsynaptic motorneurons. In the adult circuit, each presynaptic interneuron (giant fiber) forms a single connection with the ipsilateral, postsynaptic motorneuron (TTMn). Using new tools that we developed we labeled both giant fibers throughout their development and saw that these neurons overgrew their targets and formed overlapping connections. As the circuit matured, giant fibers pruned their terminals and refined their connectivity such that only a single postsynaptic connection remained with the ipsilateral target. Furthermore, if we ablated one of the two giant fibers during development in wildtype animals, the remaining giant fiber often retained excess connections with the contralateral target that persisted into adulthood. After demonstrating that the giant fiber circuit was suitable to study synaptic rearrangement, we investigated two proteins that might mediate this process. First, we were able to prevent giant fibers from refining their connectivity by knocking out highwire, a ubiquitin ligase that prevented pruning. Second, we investigated whether overexpressing Netrin (or Frazzled), part of a canonical axon guidance system, would affect the refinement of giant fiber connectivity. We found that overexpressing Netrin (or Frazzled) pre- & postsynaptically resulted in some giant fibers forming or retaining excess connections, while exclusively presynaptic (or postsynaptic) expression of either protein had no effect. We further showed that by simultaneously reducing (Slit-Robo) midline repulsion and elevating Netrin (or Frazzled) pre- & postsynaptically, we significantly enhanced the proportion of giant fibers that formed excess connections. Our findings suggest that Netrin-Frazzled and Slit-Robo signaling play a significant role in refining synaptic circuits and shaping giant fiber circuit connectivity.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004758, http://purl.flvc.org/fau/fd/FA00004758
Subject Headings: Drosophila melanogaster--Cytogenetics., Genetic transcription., Transcription factors., Cellular signal transduction., Cellular control mechanisms., Cell receptors.
Format: Document (PDF)

Title: Highwire coordinates synapse formation and maturation by regulating both a map kinase cascade and the ability of the axon to respond to external cues in the giant fiber system of Drosophila Melanogaster.
Creator: Borgen, Melissa A., Murphey, Rodney K., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The ubiquitin ligase Highwire is responsible for cell-autonomously promoting synapse formation in the Drosophila Giant Fiber system. highwire mutants show defects in synaptic function and extra branching at the axon terminal, corresponding to transient branching that occur in the course of giant synapse formation during metamorphosis. The MAP kinase pathway, including Wallenda and JNK/Basket, plus the transcription factor Jun, act to suppress synaptic function and axon pruning in a dosage...
Show moreThe ubiquitin ligase Highwire is responsible for cell-autonomously promoting synapse formation in the Drosophila Giant Fiber system. highwire mutants show defects in synaptic function and extra branching at the axon terminal, corresponding to transient branching that occur in the course of giant synapse formation during metamorphosis. The MAP kinase pathway, including Wallenda and JNK/Basket, plus the transcription factor Jun, act to suppress synaptic function and axon pruning in a dosage sensitive manner, suggesting different molecular mechanisms downstream of the MAP kinase pathway govern function and pruning. A novel role for Highwire is revealed, regulating the giant fiber axon’s ability to respond to external cues regulated by Fos. When expression of the transcription factor Fos is disrupted in the post-synaptic TTMn or surrounding midline glia of highwire mutants, the giant fiber axons show a marked increase in axon overgrowth and midline crossing. However, synaptic function is rescued by the cell nonautonomous manipulation of Fos, indicating distinct mechanisms downstream of Highwire regulating synaptic function and axon morphology.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004081, http://purl.flvc.org/fau/fd/FA00004081
Subject Headings: Cell differentiation, Cellular control mechanisms, Cellular signal transduction, Drosophila melanogaster -- Cytogenetics, Gene expression, Genetic transcription
Format: Document (PDF)

Title: Methionine sulfoxide reductase (Msr) deficiency leads to a reduction of dopamine levels in Drosophila.
Creator: Hernandez, Caesar, Binninger, David, Weissbach, Herbert, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Biological homeostasis relies on protective mechanisms that respond to cellular oxidation caused primarily by free radical reactions. Methionine sulfoxide reductases (Msr) are a class of enzymes that reverse oxidative damage to methionine in proteins. The focus of this study is on the relationship between Msr and dopamine levels in Drosophila. Dopaminergic neurons in Drosophila have comparable roles to those found in humans. A deficit in dopamine leads to the onset of many neurological...
Show moreBiological homeostasis relies on protective mechanisms that respond to cellular oxidation caused primarily by free radical reactions. Methionine sulfoxide reductases (Msr) are a class of enzymes that reverse oxidative damage to methionine in proteins. The focus of this study is on the relationship between Msr and dopamine levels in Drosophila. Dopaminergic neurons in Drosophila have comparable roles to those found in humans. A deficit in dopamine leads to the onset of many neurological disorders including the loss of fine motor control—a neurodegenerative condition characteristic of Parkinson’s disease (PD). We found that dopamine levels in the heads of MsrAΔ/ΔBΔ/Δ mutants are significantly reduced in comparison to MsrA ⁺/⁺ B⁺/⁺ heads. In addition, wefound protein and expression levels are markedly reduced in an Msr-deficient system. Our findings suggest an important role for the Msr system in the CNS.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004202, http://purl.flvc.org/fau/fd/FA00004202
Subject Headings: Cellular signal transduction, Dopamine -- Receptors, Drosophila melanogaster -- Genetics, Mitochondrial pathology, Proteins -- Chemical modification
Format: Document (PDF)

Title: Netrin-Frazzled signaling instructs synaptogenesis and plasticity at an identified central synapse in Drosophila.
Creator: Orr, Brian, Murphey, Rodney K., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The classic guidance molecules, Netrin and its receptor Frazzled (Fra), dictate the strength of synaptic connections in the giant fiber system (GFS) of Drosophila melanogaster by regulating gap junction localization in the pre-synaptic terminal. In Netrin mutant animals the synaptic coupling between a giant interneuron and the jump motor neuron was weakened. Dye-coupling between these two neurons was severely compromised or absent. These mutants exhibited anatomically and physiologically...
Show moreThe classic guidance molecules, Netrin and its receptor Frazzled (Fra), dictate the strength of synaptic connections in the giant fiber system (GFS) of Drosophila melanogaster by regulating gap junction localization in the pre-synaptic terminal. In Netrin mutant animals the synaptic coupling between a giant interneuron and the jump motor neuron was weakened. Dye-coupling between these two neurons was severely compromised or absent. These mutants exhibited anatomically and physiologically defective synapses between the giant fiber (GF) and tergotrochanteral motor neuron (TTMn). In cases where Netrin mutants displayed apparently normal synaptic anatomy, half of the specimens exhibited physiologically defective synapses. Dye-coupling between the giant fiber and the motor neuron was reduced or eliminated, suggesting that gap junctions were disrupted in the Netrin mutants. When we examined the gap junctions with antibodies to Shaking-B Innexin (ShakB), they were significantly decreased or absent in the pre-synaptic terminal of the mutant GF. This data is the first to show that Netrin and Frazzled regulate placement of gap junctions pre-synaptically at a central synapse. In the Drosophila Giant Fiber System, we demonstrate a mechanism that ensures the monoinnervation of two homologous motor neurons by two homologous interneurons. In a scenario where both interneurons could synapse with both motor neuron targets, each interneuron exclusively synapsed with only one target and the circuit functions at normal physiological levels. This innervation pattern depended on the ratio of netrin-to-frazzled expression. When Netrin was over expressed in the system, shifting the ratio in favor of Netrin, both interneurons synapsed with both target motor neurons and physiological function was reduced. This resulted in the polyinnervationof a single target. In contrast, when Frazzled was over expressed in the system, one interneuron innervated both targets and excluded the remaining interneuron from making any synaptic contact. This resulted in a single interneuron mono-innervating both motor neurons and physiological function was mutant. The orphaned interneuron made no synaptic contact with either motor neuron target. Physiological function was only normal when the Netrin-Frazzled ratio was at endogenous levels and each GF monoinnervated one motor neuron. When we examined the gap junctions at this synapse in experimental animals, there was a significant reduction of gap junction hemichannels in the presynaptic terminal of axons that deviated from normal innervation patterns. While the synapse dyecoupled, the reduction in gap junction hemichannels reduced function in the circuit.
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Date Issued: 2013
PURL: http://purl.flvc.org/fau/fd/FA0004041
Subject Headings: Cellular control mechanisms, Cellular signal transduction, Drosophila melanogaster -- Cytogenetics, Genetic transcription, Transcription factors
Format: Document (PDF)

Title: Comprehensive study of the ZAD family of zinc finger transcription factors in Drosophila melanogaster.
Creator: Krystel, Joseph., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The zinc finger associated domain (ZAD) family of transcription factors from Drosophila melanogaster is not well described in the literature, in part because it is very difficult to study by traditional mutagenesis screens. Bioinformatic studies indicate this is due to overlapping functions remaining after a recent evolutionary divergence. I set out to use in vitro-binding techniques to identify the characteristics of the ZAD family and test this theory. I have constructed glutathione S...
Show moreThe zinc finger associated domain (ZAD) family of transcription factors from Drosophila melanogaster is not well described in the literature, in part because it is very difficult to study by traditional mutagenesis screens. Bioinformatic studies indicate this is due to overlapping functions remaining after a recent evolutionary divergence. I set out to use in vitro-binding techniques to identify the characteristics of the ZAD family and test this theory. I have constructed glutathione S-transferase (GST)-ZAD domain chimeric proteins for use in pull down protein binding assays,and GST-Zinc finger (ZnF) array domain chimera for electrophoretic mobility shift assays (EMSA). Protein binding assays indicated two putative conserved interactors, similar to the analogous KRAB system in mammals. ... Competitive bindings were carried out to show a specificity of binding conferred by the identified conserved positions. While the consensus binding sites show relatively few similarities, the predicted target genes identified by the consensus binding sites show significant overlap. The nature of this overlap conforms to the known characteristics of the ZAD family but points to a more positive selection to maintain conservation of function.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3355627
Subject Headings: Cellular signal transduction, Drosophila melanogaster, Cytogenetics, Transcription factors, Zinc-finger proteins, Synthesis, Genetic transcription, Regulation, Gene expression
Format: Document (PDF)

Title: Elucidation of the features of the zinc finger associated domain (ZAD) family of transportation factors in Drosophila melanogaster.
Creator: Krystel, Joseph., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The zinc finger associated domain (ZAD) containing family of transcription factors is not well described in the literature, in part because it is very difficult to study by mutagenesis. We used in vitro-binding techniques to identify characteristics of the ZAD family, by constructing glutathione Stransferase (GST)-ZAD domain chimeric proteins for use in protein binding assays, and GST-Zinc finger array domain chimera for binding site selections. Protein binding assays indicated a possible...
Show moreThe zinc finger associated domain (ZAD) containing family of transcription factors is not well described in the literature, in part because it is very difficult to study by mutagenesis. We used in vitro-binding techniques to identify characteristics of the ZAD family, by constructing glutathione Stransferase (GST)-ZAD domain chimeric proteins for use in protein binding assays, and GST-Zinc finger array domain chimera for binding site selections. Protein binding assays indicated a possible shared cofactor, as seen in the analogous KRAB system in mammals. DNA binding assays have provided a consensus binding sequence for five of the ZAD proteins, consistent with previously reported work on ZAD and unpublished work on mammalian transcription factors. Research is ongoing with an additional ~50 ZAD proteins to more fully map the binding characters of ZAD proteins.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/186768
Subject Headings: Cellular signal transduction, Drosophila melanogaster, Cytogenetics, Transcription factors, Zinc-finger proteins, Synthesis, Genetic transcription, Regulation, Gene expression
Format: Document (PDF)

Title: Identification of longitudinals lacking (LOLA) target genes in Drosophila melanogaster.
Creator: Qureshi, Bazila., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Longitudinals lacking gene (LOLA) is a transcription factor that is involved in a variety of axon guidance decisions in Drosophila melanogaster nervous system. Besides having a role as an epigenetic silencer and in the programmed cell death in Drosophila's ovary, this gene is also an example of complex transcription unit. LOLA is a transcription repressor and can generate 17 DNA - binding isoforms, through alternative splicing, each containing distinct zinc-finger proteins. This unique...
Show moreLongitudinals lacking gene (LOLA) is a transcription factor that is involved in a variety of axon guidance decisions in Drosophila melanogaster nervous system. Besides having a role as an epigenetic silencer and in the programmed cell death in Drosophila's ovary, this gene is also an example of complex transcription unit. LOLA is a transcription repressor and can generate 17 DNA - binding isoforms, through alternative splicing, each containing distinct zinc-finger proteins. This unique DNAbinding binding sequence to which LOLA-ZFP binds has been determined for four of the lola isoforms F, J, P and K. Also, bioinformatics' tool approach has been taken to identify the target genes that are regulated by these four LOLA splice variants. Future work will be done for the five other LOLA isoforms to categorize their putative DNA-binding sequences and subsequently their protein interactions.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/2684893
Subject Headings: Transcription factors, Cellular signal transduction, Zinc-finger proteins, Synthesis, Genetic transcription, Regulation, Drosophila melanogaster, Cytogenetics, Gene expression
Format: Document (PDF)

Title: Identification and characterization of mutations in the Drosophila mitochondrial translation elongation factor iconoclast.
Creator: Trivigno, Catherine F., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Mitochondrial disorders resulting from defects in oxidative phosphorylation are the most common form of inherited metabolic disease. Mutations in the human mitochondrial translation elongation factor GFM1 have recently been shown to cause the lethal pediatric disorder Combined Oxidative Phosphorylation Deficiency Syndrome (COXPD1). Children harboring mutations in GFM1 exhibit severe developmental, metabolic and neurological abnormalities. This work describes the identification and extensive...
Show moreMitochondrial disorders resulting from defects in oxidative phosphorylation are the most common form of inherited metabolic disease. Mutations in the human mitochondrial translation elongation factor GFM1 have recently been shown to cause the lethal pediatric disorder Combined Oxidative Phosphorylation Deficiency Syndrome (COXPD1). Children harboring mutations in GFM1 exhibit severe developmental, metabolic and neurological abnormalities. This work describes the identification and extensive characterization of the first known mutations in iconoclast (ico), the Drosophila orthologue of GFM1. Expression of human GFM1 can rescue ico null mutants, demonstrating functional conservation between the human and fly proteins. While point mutations in ico result in developmental defects and death during embryogenesis, animals null for ico survive until the second or third instar larval stage. These results indicate that in addition to loss-of-function consequences, point mutations in ico appear to produce toxic proteins with antimorphic or neomorphic effects. Consistent with this hypothesis, transgenic expression of a mutant ICO protein is lethal when expressed during development and inhibits growth when expressed in wing discs. In addition, animals with a single copy of an ico point mutation are more sensitive to acute hyperthermic or hypoxic stress. Removal of the positively-charged tail of the protein abolishes the toxic effects of mutant ICO, demonstrating that this domain is necessary for the harmful gain-of-function phenotypes observed in ico point mutants., Further, expression of GFP-tagged constructs indicates that the C-terminal tail enhances ectopic nuclear localization of mutant ICO, suggesting that mislocalization of the protein may play a role in the antimorphic effects of mutant ICO. Taken together, these results illustrate that in addition to loss-of-function effects, gain-of-function effects can contribute significantly to the pathology caused by mutation in mitochondrial translation elongation factors.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/2705081
Subject Headings: Drosophila melanogaster, Cytogenetics, Mutation (Biology), Mitochondrial DNA, Cell metabolism, Cellular signal transduction, Oxidation, Physiological, Genetic transcription, Regulation
Format: Document (PDF)

Title: Highwire's characterization and signaling roles in Drosophila central synapse formation.
Creator: Rowland, Kimberly Diane., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The assembly and maintenance of central synapses is a complex process, requiring myriad genes and their products. Highwire is a large gene containing a RING domain, characteristic of ubiquitin E3 ligases. Highwire has been shown to restrain axon growth and control synaptogenesis at a peripheral synapse. Here I examine the roles of Highwire at a central synapse in the adult Drosophila Giant Fiber System (GFS). Highwire is indeed necessary for proper axonal growth as well as synaptic...
Show moreThe assembly and maintenance of central synapses is a complex process, requiring myriad genes and their products. Highwire is a large gene containing a RING domain, characteristic of ubiquitin E3 ligases. Highwire has been shown to restrain axon growth and control synaptogenesis at a peripheral synapse. Here I examine the roles of Highwire at a central synapse in the adult Drosophila Giant Fiber System (GFS). Highwire is indeed necessary for proper axonal growth as well as synaptic transmission in the GFS. Differences arise between the central synapse and the neuromuscular junction (NMJ), where highwire was initially characterized : expresion from the postsynaptic cell can rescue highwire synaptic defects, which is not seen at the NMJ. In addition, a MAP kinase signaling pathway regulated by highwire at the NMJ has differing roles at a central synapse. Wallenda MAPK can rescue not only the highwire anatomical phenotype but also the defects seen in transmission. Another distinction is seen here : loss of function basket and Dfos enhance the highwire anatomical phenotype while expression of dominant negative basket and Dfos suppress the highwire phenotype. As a result we have compared the signaling pathway in flies and worms and found that the NMJ in the two organisms use a parallel pathway while the central synapse uses a distinct pathway.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3352826
Subject Headings: Cellular control mechanisms, Cellular signal transduction, Cell differentiation, Gene expression, Genetic transcription, Transcription factors, Drosophila melanogaster, Cytogenetics
Format: Document (PDF)

Title: Methionine sulfoxide reductase (MSR) modulates lifespan andLocomotion in drosophila melanogaster.
Creator: Bruce, Lindsay, Binninger, David, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Oxidative stress is considered a major factor in the etiology of age related diseases and the aging process itself. Organisms have developed mechanisms to protect against oxidative damage resulting from increased production of reactive oxygen species during aging. One of the major antioxidant systems is the methionine sulfoxide reductase (Msr) enzyme family. The two major Msr enzymes, MsrA and MsrB, can stereospecifically reduce the S and R epimers, respectively, of methionine sulfoxide in...
Show moreOxidative stress is considered a major factor in the etiology of age related diseases and the aging process itself. Organisms have developed mechanisms to protect against oxidative damage resulting from increased production of reactive oxygen species during aging. One of the major antioxidant systems is the methionine sulfoxide reductase (Msr) enzyme family. The two major Msr enzymes, MsrA and MsrB, can stereospecifically reduce the S and R epimers, respectively, of methionine sulfoxide in proteins back to methionine. This study, using Drosophila melanogaster, decribes the first animal system lacking both MsrA and MsrB. The loss of either MsrA or MsrB had no effect on lifespan in Drosophila, but loss of MsrB results in a slight decrease in locomotor activity from middle age onward. Double mutants lacking both forms of Msr have a significantly decreased lifespan and decreased locomotor activity at all ages examined. The double Msr mutants had no detectable increase in protein oxidation or decrease in mitochondrial function and were not more sensitive to oxidative stress. These results suggested that other cellular antioxidant systems were protecting the flies against oxidative damage and the decreased life span observed in the double knockouts was not due to widespread oxidative damage. However, one cannot exclude limited oxidative damage to a specific locus or cell type. In this regard, it was observed that older animals, lacking both MsrA and MsrB, have significantly reduced levels of dopamine, suggesting there might be oxidative damage to the dopaminergic neurons. Preliminary results also suggest that the ratio of F to G actin is skewed towards G actin in all mutants. The present results could have relevance to the loss of dopaminergic neurons in Parkinson’s disease.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004431, http://purl.flvc.org/fau/fd/FA00004431
Subject Headings: Aging -- Molecular aspects, Cellular signal transduction, Drosophila melanogaster -- Genetics, Mitochondrial pathology, Mutation (Biology), Oxidative stress, Proteins -- Chemical modification
Format: Document (PDF)

Title: Presynaptic Determinants of Synaptic Strength and Energy Efficiency at Drosophila Neuromuscular Junctions.
Creator: Lu, Zhongmin, Macleod, Gregory, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Changes in synaptic strength underlie synaptic plasticity, the cellular substrate for learning and memory. Disruptions in the mechanisms that regulate synaptic strength closely link to many developmental, neurodegenerative and neurological disorders. Release site probability (PAZ) and active zone number (N) are two important presynaptic determinants of synaptic strength; yet, little is known about the processes that establish the balance between N and PAZ at any synapse. Furthermore, it is...
Show moreChanges in synaptic strength underlie synaptic plasticity, the cellular substrate for learning and memory. Disruptions in the mechanisms that regulate synaptic strength closely link to many developmental, neurodegenerative and neurological disorders. Release site probability (PAZ) and active zone number (N) are two important presynaptic determinants of synaptic strength; yet, little is known about the processes that establish the balance between N and PAZ at any synapse. Furthermore, it is not known how PAZ and N are rebalanced during synaptic homeostasis to accomplish circuit stability. To address this knowledge gap, we adapted a neurophysiological experimental system consisting of two functionally differentiated glutamatergic motor neurons (MNs) innervating the same target. Average PAZ varied between nerve terminals, motivating us to explore benefits for high and low PAZ, respectively. We speculated that high PAZ confers high-energy efficiency. To test the hypothesis, electrophysiological and ultrastructural measurements were made. The terminal with the highest PAZ released more neurotransmitter but it did so with the least total energetic cost. An analytical model was built to further explore functional and structural aspects in optimizing energy efficiency. The model supported that energy efficiency optimization requires high PAZ. However, terminals with low PAZ were better able to sustain neurotransmitter release. We suggest that tension between energy efficiency and stamina sets PAZ and thus determines synaptic strength. To test the hypothesis that nerve terminals regulate PAZ rather than N to maintain synaptic strength, we induced sustained synaptic homeostasis at the nerve terminals. Ca2+ imaging revealed that terminals of the MN innervating only one muscle fiber utilized greater Ca2+ influx to achieve compensatory neurotransmitter release. In contrast, morphological measurements revealed that terminals of the MN inner vating multiple postsynaptic targets utilized an increase in N to achieve compensatory neurotransmitter release, but this only occurred at the terminal of the affected postsynaptic target. In conclusion, this dissertation provides several novel insights into a prominent question in neuroscience: how is synaptic strength established and maintained. The work indicates that tension exists between energy efficiency and stamina in neurotransmitter release likely influences PAZ. Furthermore, PAZ and N are rebalanced differently between terminals during synaptic homeostasis.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004519, http://purl.flvc.org/fau/fd/FA00004519
Subject Headings: Drosophila melanogaster--Nervous system., Drosophila melanogaster--Cytogenetics., Fruit-flies--Development., Fruit-flies--Nervous system., Genetic transcription., Transcription factors., Cellular signal transduction., Cellular control mechanisms., Myoneural junction.
Format: Document (PDF)

Title: Phenotypic and behavioral effects of methionine sulfoxide reductase deficiency and oxidative stress in Drosophila melanogaster.
Creator: Mulholland, Kori., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Harman's theory of aging proposes that a buildup of damaging reactive oxygen species (ROS) is one of the primary causes of the deleterious symptoms attributed to aging. Cellular defenses in the form of antioxidants have evolved to combat ROS and reverse damage; one such group is the methionine sulfoxide reductases (Msr), which function to reduce oxidized methionine. MsrA reduces the S enantiomer of methionine sulfoxide, Met-S-(o), while MsrB reduces the R enantiomer, Met-R-(o). The focus of...
Show moreHarman's theory of aging proposes that a buildup of damaging reactive oxygen species (ROS) is one of the primary causes of the deleterious symptoms attributed to aging. Cellular defenses in the form of antioxidants have evolved to combat ROS and reverse damage; one such group is the methionine sulfoxide reductases (Msr), which function to reduce oxidized methionine. MsrA reduces the S enantiomer of methionine sulfoxide, Met-S-(o), while MsrB reduces the R enantiomer, Met-R-(o). The focus of this study was to investigate how the absence of one or both forms of Msr affects locomotion in Drosophila using both traditional genetic mutants and more recently developed RNA interference (RNAi) strains. Results indicate that lack of MsrA does not affect locomotion. However, lack of MsrB drastically reduces rates of locomotion in all age classes. Furthermore, creation of an RNAi line capable of knocking down both MsrA and MsrB in progeny was completed.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3362558
Subject Headings: Drosophila melanogaster, Genetics, Aging, Molecular aspects, Oxidative stress, Mitochondrial pathology, Cellular signal transduction, Oxidation-reduction reaction, Biochemical markers, Mutation (Biology)
Format: Document (PDF)

Title: Reduced Reproductivity and Larval Locomotion in the Absence of Methionine Sulfoxide Reductase in Drosophila.
Creator: Singkornrat, Diana, Binninger, David, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The inevitable aging process can be partially attributed to the accumulation of oxidative damage that results from the action of free radicals. Methionine sulfoxide reductases (Msr) are a class of enzymes that repair oxidized methionine residues. The two known forms of Msr are MsrA and MsrB which reduce the R- and S- enantiomers of methionine sulfoxide, respectively. Our lab has created the first genetic animal model that is fully deficient for any Msr activity. Previously our lab showed that...
Show moreThe inevitable aging process can be partially attributed to the accumulation of oxidative damage that results from the action of free radicals. Methionine sulfoxide reductases (Msr) are a class of enzymes that repair oxidized methionine residues. The two known forms of Msr are MsrA and MsrB which reduce the R- and S- enantiomers of methionine sulfoxide, respectively. Our lab has created the first genetic animal model that is fully deficient for any Msr activity. Previously our lab showed that these animals exhibit a 20 hour delay in development of the third instar larvae (unpublished data). My studies have further shown that the prolonged third-instar stage is due to a reduced growth rate associated with slower food intake and a markedly slower motility. These Msr-deficient animals also exhibit decreased egg-laying that can be attributed to a lack of female receptivity to mating.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004777, http://purl.flvc.org/fau/fd/FA00004777
Subject Headings: Proteins--Chemical modification., Oxidative stress., Oxidation-reduction reaction., Drosophila melanogaster--Genetics., Mitochondrial pathology., Cellular signal transduction., Mutation (Biology), Aging--Molecular aspects.
Format: Document (PDF)

Cellular signal transduction (11)	+ -
Drosophila melanogaster (8)	+ -
Genetic transcription (7)	+ -
Cytogenetics (5)	+ -
Gene expression (5)	+ -

Mutation (Biology) (5)	+ -
Transcription factors (5)	+ -
Mitochondrial pathology (4)	+ -
Regulation (4)	+ -
Cellular control mechanisms (3)	+ -
Cellular signal transduction. (3)	+ -
Genetic transcription. (3)	+ -
Oxidative stress (3)	+ -
Synthesis (3)	+ -
Transcription factors. (3)	+ -
Zinc-finger proteins (3)	+ -
Aging -- Molecular aspects (2)	+ -
Cell differentiation (2)	+ -
Cellular control mechanisms. (2)	+ -
Drosophila melanogaster -- Cytogenetics (2)	+ -
Drosophila melanogaster -- Genetics (2)	+ -
Drosophila melanogaster--Cytogenetics. (2)	+ -
Genetics (2)	+ -
Proteins -- Chemical modification (2)	+ -
Aging (1)	+ -
Aging--Molecular aspects. (1)	+ -
Biochemical markers (1)	+ -
Cell cycle. (1)	+ -
Cell metabolism (1)	+ -
Cell receptors. (1)	+ -

Charles E. Schmidt College of Science (17)	+ -
Department of Biological Sciences (17)	+ -
Florida Atlantic University (9)	+ -
Binninger, David (4)	+ -
Murphey, Rodney K. (3)	+ -

Krystel, Joseph. (2)	+ -
Borgen, Melissa A. (1)	+ -
Bruce, Lindsay (1)	+ -
Dawson-Scully, Ken (1)	+ -
Hausman, William (1)	+ -
Hernandez, Caesar (1)	+ -
Keene, Alex C. (1)	+ -
Lloyd, Brandon N. (1)	+ -
Lu, Zhongmin (1)	+ -
Macleod, Gregory (1)	+ -
Mejia, Monica (1)	+ -
Mulholland, Kori. (1)	+ -
Murakami, Kazuma N. (1)	+ -
Orr, Brian (1)	+ -
Qureshi, Bazila. (1)	+ -
Rowland, Kimberly Diane. (1)	+ -
Singh, Shweta (1)	+ -
Singkornrat, Diana (1)	+ -
Trivigno, Catherine F. (1)	+ -
Weissbach, Herbert (1)	+ -

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