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Adopting the orphan: determining the role of the motor protein KIF9 during the cell cycle
Title
Adopting the orphan: determining the role of the motor protein KIF9 during the cell cycle.
Creator
Rivera Rios, Miguel E., Harriet L. Wilkes Honors College
Abstract/Description
The kinesin superfamily of microtubule motor proteins is subdivided into families based upon structure and function. KIF9 is the founding member of the Kinesin-9 family, which is a largely uncharacterized group of kinesins. It was originally identified by sequence homology to other kinesins. Subsequent studies have shown that KIF9 interacts with proteins involved in cell shape remodeling, cell migration and proper centrosomal positioning. We have examined KIF9 function in mammalian cells...
Show moreThe kinesin superfamily of microtubule motor proteins is subdivided into families based upon structure and function. KIF9 is the founding member of the Kinesin-9 family, which is a largely uncharacterized group of kinesins. It was originally identified by sequence homology to other kinesins. Subsequent studies have shown that KIF9 interacts with proteins involved in cell shape remodeling, cell migration and proper centrosomal positioning. We have examined KIF9 function in mammalian cells using shRNA-mediated knockdown and GFP-plasmid overexpression. By knocking dow KIF9 expression in these cells, we have seen several effects on normal cell cycle progression. Using various cell cycle markers, we have observed a decrease in the number of cells in late S phase. In addition, there is a marked increase in the number of cells in early mitosis in unexpected time intervals. We propose that KIF9 is required for proper cell progression, via a potentially novel checkpoint mechanism.
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Date Issued
2012
PURL
http://purl.flvc.org/FAU/3359321, http://purl.flvc.org/fau/fd/FADT3359321
Subject Headings
Cell organelles, Formation, Cellular signal transduction, Protoplasmic streaming, Cells, Motility, Cell division, Research
Format
Document (PDF)
Deamplification of supernumerary centrosomes by centrosomal clustering
Title
Deamplification of supernumerary centrosomes by centrosomal clustering.
Creator
Thomas, Ezekiel., Harriet L. Wilkes Honors College
Abstract/Description
Supernumerary centrosomes can arise in a cell through a variety of methods. The presence of supernumerary centrosomes has been observed in nearly all types of cancer and promotes chromosomal instability, with rates of incident increasing as the cancer progresses. An oral squamous cell carcinoma line was treated with hydroxyurea to induce supernumerary centrosomes in the cells. NuMA was then knocked down using shRNA to promote centrosomal clustering and bipolar mitotic division in cells with...
Show moreSupernumerary centrosomes can arise in a cell through a variety of methods. The presence of supernumerary centrosomes has been observed in nearly all types of cancer and promotes chromosomal instability, with rates of incident increasing as the cancer progresses. An oral squamous cell carcinoma line was treated with hydroxyurea to induce supernumerary centrosomes in the cells. NuMA was then knocked down using shRNA to promote centrosomal clustering and bipolar mitotic division in cells with supernumerary centrosomes. Immunofluorescence with an antibody against SAS 6 accuately stained the centrioles for observation. The cells exhibiting supernumerary centrosomes undergoing bipolar mitotic division were studied to look for a possible pattern in centrosomal clustering where the majority of centrosomes are at one pole with a single centrosome at the other pole. Initial results suggest the presence of such a mechanism, which would describe a previously unknown mechanism for cells to deamplify supernumerary centrosomes by centrosomal clustering.
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Date Issued
2012
PURL
http://purl.flvc.org/FAU/3359328
Subject Headings
Centrosomes, Cell division, Cellular signal transduction, Cancer, Genetic aspects
Format
Document (PDF)
Devising a noncancerous model system to study multipolar spindle formation
Title
Devising a noncancerous model system to study multipolar spindle formation.
Creator
Nagarsheth, Nisha., Harriet L. Wilkes Honors College
Abstract/Description
Aneuploid tumor cells have characteristically unstable genomes which can be caused by mitotic defects such as multipolar spindles. Multipolarity relies upon the presence of extra centrosomes to form. However, some cells, both cancerous and noncancerous are able to avoid the formation of multipolar spindles through centrosomal clustering. Previous research has shown that there are a large number of genes whose activity contributes to the clustering activity, making analysis of individual...
Show moreAneuploid tumor cells have characteristically unstable genomes which can be caused by mitotic defects such as multipolar spindles. Multipolarity relies upon the presence of extra centrosomes to form. However, some cells, both cancerous and noncancerous are able to avoid the formation of multipolar spindles through centrosomal clustering. Previous research has shown that there are a large number of genes whose activity contributes to the clustering activity, making analysis of individual components of the process difficult. In order to better understand centrosomal clustering in cancer cells, we induced supernumerary centrosomes in a genomically normal cell line, RPE, to observe how the normal cells cope with extra centrosomes. Using colcemid to induce extra centrosomes in the RPE cell line, we observed an intact clustering mechanism in fixed cells. Further manipulation of the cells has allowed us to induce multipolarity in this cell line using various disrupters of cell-cycle checkpoint and dynein function.
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Date Issued
2010
PURL
http://purl.flvc.org/FAU/3335107
Subject Headings
Centrosomes, Research, Cancer, Genetic aspects, Cellular signal transduction, Cell division
Format
Document (PDF)
Manipulation of normal cells to produce a cancer-like mitotic phenotype
Title
Manipulation of normal cells to produce a cancer-like mitotic phenotype.
Creator
Luffman, Christina., Harriet L. Wilkes Honors College
Abstract/Description
Most tumors contain multiple karyotypes due to genomic instability gained through chromosomal segregational defects. The variability of genomic changes within a population makes it difficult to study specific processes without the existence of confounding mutations. My project is to create a model system for observation of mitotic defects, specifically multipolar spindles, in a normal cell line, where the genome is intact. Induction of centrosome amplification is required for formation of...
Show moreMost tumors contain multiple karyotypes due to genomic instability gained through chromosomal segregational defects. The variability of genomic changes within a population makes it difficult to study specific processes without the existence of confounding mutations. My project is to create a model system for observation of mitotic defects, specifically multipolar spindles, in a normal cell line, where the genome is intact. Induction of centrosome amplification is required for formation of multipolar spindles. Treatments with colcemid showed a 10% increase in abnormal centrosome numbers over control. However, treatment with hydroxyurea and transfection of hMPSl showed little increase. Extra centrosomes are insufficient to drive multipolarity, therefore, I am using siRNA-mediated knockdown of Nek2 or HSET to decluster the extra centrosomes. Successful declustering will preferably show an increase in multipolar frequency, allowing us to study the formation and resolution of these structres to better understand how they contribute to aneuploidy and tumor progression.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/3325079
Subject Headings
Cell division, Karyokinesis, Cancer, Genetic aspects, Genomics, Cellular signal transduction, Centrosomes
Format
Document (PDF)