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Posttranscriptional regulation of tropomyosin expression by myofibril inducing RNA (MIR) during axolotl embryonic heart development
Title
Posttranscriptional regulation of tropomyosin expression by myofibril inducing RNA (MIR) during axolotl embryonic heart development.
Creator
Jia, Pingping, Florida Atlantic University, Lemanski, Larry F., Charles E. Schmidt College of Medicine, Department of Biomedical Science
Abstract/Description
A naturally-occurring recessive lethal mutation in axolotls, Ambystoma mexicanum, is an intriguing model for studying tropomyosin expression regulation. Homozygous embryos(c/c) form hearts that are deficient in tropomyosin, lack organized myofibrils and fail to beat. Previous studies have shown that a non-coding RNA gene, MIR (Myofibril Inducing RNA), is sufficient to rescue the non-beating homozygous recessive mutant hearts by promoting sarcomeric tropomyosin expression that leads to...
Show moreA naturally-occurring recessive lethal mutation in axolotls, Ambystoma mexicanum, is an intriguing model for studying tropomyosin expression regulation. Homozygous embryos(c/c) form hearts that are deficient in tropomyosin, lack organized myofibrils and fail to beat. Previous studies have shown that a non-coding RNA gene, MIR (Myofibril Inducing RNA), is sufficient to rescue the non-beating homozygous recessive mutant hearts by promoting sarcomeric tropomyosin expression that leads to formation of organized myofibrils and beating hearts. Real time RT-PCR reveals that mutant hearts express the same level mRNA of the alpha-tropomyosin and TM4 type tropomyosin (ATmC-3) gene as normal embryonic hearts. These genes show no differences with regard to the splicing patterns of normal and mutant. Using protease inhibitor LLnL and E-64d treatments and two-dimensional Western blots of normal and mutant hearts, it is found that mutant hearts express all tropomyosin protein isoforms as normal hearts but protein expression are at low levels. These studies suggest that there is a failure in the translational or posttranslational control mechanisms for tropomyosin protein synthesis in cardiac mutant axolotl hearts during development.
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Date Issued
2006
PURL
http://purl.flvc.org/fcla/dt/13380
Subject Headings
Medical genetics, Molecular biology, Cell differentiation, Gene expression, Axolotls--Development, Heart--Growth--Molecular aspects
Format
Document (PDF)
Fetal and Adult Human Heart RNA Promotes Myofibrillogenesis and Stimulates a Heart Beat in Cardiac Non-function Mutant Mexican Axolotl Hearts in Organ Culture
Title
Fetal and Adult Human Heart RNA Promotes Myofibrillogenesis and Stimulates a Heart Beat in Cardiac Non-function Mutant Mexican Axolotl Hearts in Organ Culture.
Creator
Rueda-de-Leon, Elena, Lemanski, Larry F., Florida Atlantic University, Charles E. Schmidt College of Medicine, Department of Biomedical Science
Abstract/Description
The Mexican axolotl (Ambystoma mexicanum) carries a cardiac lethal mutation resulting in mutant embryos with no heartbeat. This homozygous recessive gene results in tropomyosin deficiency and absence of organized myofibrils. Co-culturing mutant hearts with bioactive RNA, termed myofibril-inducing RNA (MIR), from normal axolotl embryonic anterior endoderm causes the mutant hearts to beat. It is hypothesized that the secondary structure of the MIR binds a specific protein(s) and this is...
Show moreThe Mexican axolotl (Ambystoma mexicanum) carries a cardiac lethal mutation resulting in mutant embryos with no heartbeat. This homozygous recessive gene results in tropomyosin deficiency and absence of organized myofibrils. Co-culturing mutant hearts with bioactive RNA, termed myofibril-inducing RNA (MIR), from normal axolotl embryonic anterior endoderm causes the mutant hearts to beat. It is hypothesized that the secondary structure of the MIR binds a specific protein(s) and this is required to synthesize tropomyosin and form organized myofibrils. In this study mutant hearts are co-cultured with human fetal and adult heart total RNA to assess rescue of the mutant hearts. Results show that both human fetal and adult heart total RNA rescue the mutant condition in a manner similar to the MIR. Thus, the MIR human functional homologs induce events leading to normal heart differentiation and function. This finding may help people with heart muscle damage regain normal heart function again.
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Date Issued
2007
PURL
http://purl.flvc.org/fau/fd/FA00000823
Subject Headings
Axolotls--Development, Heart--Hypertrophy, Molecular genetics--Research, Ibises--Reproduction
Format
Document (PDF)
The Application of Yeast Three-Hybrid Technology in the Mexican Axolotl (Ambystoma mexicanum) System.
Title
The Application of Yeast Three-Hybrid Technology in the Mexican Axolotl (Ambystoma mexicanum) System.
Creator
Maier, Jennifer A., Lemanski, Larry F., Florida Atlantic University
Abstract/Description
The Mexican axolotl, Ambystoma mexicanum, possesses a naturally-occurring lethal mutation, designated gene "c", for cardiac non-function. Hearts form but fail to beat, lack organized myofibrils, and are deficient in tropomyosin. Treatment with a noncoding RNA MIR (Myofibril-Inducing RNA) rescues this defect in organ culture. Rescued mutant hearts have restored tropomyosin, form organized myofibrils, and beat vigorously. Studies to elucidate the mechanism of MIR heart rescue are underway....
Show moreThe Mexican axolotl, Ambystoma mexicanum, possesses a naturally-occurring lethal mutation, designated gene "c", for cardiac non-function. Hearts form but fail to beat, lack organized myofibrils, and are deficient in tropomyosin. Treatment with a noncoding RNA MIR (Myofibril-Inducing RNA) rescues this defect in organ culture. Rescued mutant hearts have restored tropomyosin, form organized myofibrils, and beat vigorously. Studies to elucidate the mechanism of MIR heart rescue are underway. Current evidence suggests that MIR acts by binding with at least two proteins. The yeast three-hybrid system is being used to screen an axolotl eDNA library for these two proteins and other possible MIR-binding candidates. This is a method utilizing two hybrid proteins and a hybrid RNA. An interaction between these three components will activate the expression of reporter genes, whose activity is assayed through phenotypical and biochemical methods. In this study, the protocol for yeast three-hybrid technology is being established for analyzing the MIR in the Mexican axolotl, cardiac mutant animal model.
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Date Issued
2007
PURL
http://purl.flvc.org/fau/fd/FA00000793
Subject Headings
Axolotls--Development, Heart--Hypertrophy, Genetic translation, Molecular genetics--Research
Format
Document (PDF)