A Specific Synthetic RNA Promotes Cardiac Myofibrillogenesis in the Mexican Axolotl

Lemanski, Larry F.; Nakatsugawa, Masako; Bhatia, Rajula; Erginel-Unaltuna, Nihan; Spinner, Belinda J.; Dube, Dipak K.

doi:10.1006/bbrc.1996.1910

Cited by 24 publications

(36 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The effect of the tropomyosin deficiency was further substantiated in the mutant heart by the findings that ectopic expression of murine alpha-tropomyosin cDNA or lipofection of purified rabbit TM protein could result in the formation of organized myofibrils [Zajdel et al, 1998]. RNA from normal axolotl heart has been shown to increase tropomyosin levels and promote myofibril formation in mutant hearts [Davis and Lemanski, 1987;Lemanski et al, 1996]. The regulatory mechanism used to promote or inhibit the translation of a specific tropomyosin is unknown.…”

Section: Discussionmentioning

confidence: 99%

Characterization of a TM‐4 type tropomyosin that is essential for myofibrillogenesis and contractile activity in embryonic hearts of the Mexican axolotl*

Spinner

Zajdel

McLean

et al. 2002

J of Cellular Biochemistry

Self Cite

View full text Add to dashboard Cite

A striated muscle isoform of a Tropomyosin (TM-4) gene was characterized and found to be necessary for contractile function in embryonic heart. The full-length clone of this isoform was isolated from the Mexican axolotl (Ambystoma mexicanum) and named Axolotl Tropomyosin Cardiac-3 (ATmC-3). The gene encoded a cardiac-specific tropomyosin protein with 284 amino acid residues that demonstrated high homology to the Xenopus cardiac TM-4 type tropomyosin. Northern blot analysis indicates a transcript of approximately 1.25 kb in size. RT-PCR and in situ hybridization demonstrated that this isoform is predominantly in cardiac tissue. Our laboratory uses an animal model that carries a cardiac lethal mutation (gene c), this mutation results in a greatly diminished level of tropomyosin protein in the ventricle. Transfection of ATmC-3 DNA into mutant hearts increased tropomyosin levels and promoted myofibrillogenesis. ATmC-3 expression was blocked in normal hearts by transfection of exon-specific anti-sense oligonucleotide (AS-ODN). RT-PCR confirmed lower transcript expression of ATmC-3 and in vitro analysis confirmed the specificity of the ATmC-3 exon 2 anti-sense oligonucleotide. These AS-ODN treated hearts also had a disruption of myofibril organization and disruption of synchronous contractions. These results demonstrated that a striated muscle isoform of the TM-4 gene was expressed embryonically and was necessary for normal structure and function of the ventricle.

show abstract

Section: Discussionmentioning

confidence: 99%

Characterization of a TM‐4 type tropomyosin that is essential for myofibrillogenesis and contractile activity in embryonic hearts of the Mexican axolotl*

Spinner

Zajdel

McLean

et al. 2002

J of Cellular Biochemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…From total conditioned medium RNA, we then cloned an RNA (MIR RNA) which rescued the mutant hearts (Lemanski et al 1996). Electron microscopy studies (Fig.…”

Section: Electron Microscopy Shows That Mir Rna Promotes Myofibrillogmentioning

confidence: 99%

A point mutation in bioactive RNA results in the failure of mutant heart correction in mexican axolotls

et al. 2003

Self Cite

View full text Add to dashboard Cite

Ambystoma mexicanum is an intriguing animal model for studying heart development because it carries a mutation in gene c. Hearts of homozygous recessive (c/c) mutant embryos do not contain organized myofibrils and fail to beat. The defect can be corrected by organ-culturing the mutant heart in the presence of RNA from anterior endoderm or endoderm/mesoderm-conditioned medium. By screening a cDNA library made of total conditioned medium RNA from normal axolotl embryonic endoderm, we isolated a single clone (MIR), the synthetic RNA from which corrects the mutant heart defect by promoting myofibrillogenesis and thus was named MIR (myofibrillogenesis inducing RNA). In the present study, we have examined MIR gene expression in mutant axolotl hearts at early pre-heart-beat developmental stages and found its quantitative expression, as detected by RT-PCR, to be the same as in normal hearts. However, careful analysis of sequence data revealed a G-->U point mutation in the mutant MIR RNA. Further computational analyses, using GENEBEE software to compare normal and mutant MIR RNAs show a significant alteration in RNA secondary structure of the point-mutated MIR RNA. The results from bioassay and confocal microscopy immunofluorescent studies demonstrate that, unlike MIR RNA derived from normal embryos, the mutated MIR RNA does not promote myofibrillogenesis in mutant embryonic hearts and fails to rescue/correct the mutant heart defect.

show abstract

“…in the regulation of contraction and its own expression regulation by other tissue specific factors using the gene c mutation animal system [Lemanski, 1976a,b;Lemanski et al, 1985Lemanski et al, , 1996LaFrance et al, 1993;Luque et al, 1994Luque et al, , 1997Gaur et al, 2001]. The troponin complex along with tropomyosin are essential for the efficient use of calcium in muscle contraction.…”

Section: Discussionmentioning

confidence: 99%

Molecular and immunohistochemical analyses of cardiac troponin T during cardiac development in the Mexican axolotl, Ambystoma mexicanum

Zhang

Pietras

Sferrazza

et al. 2006

J of Cellular Biochemistry

View full text Add to dashboard Cite

The Mexican axolotl, Ambystoma mexicanum, is an excellent animal model for studying heart development because it carries a naturally occurring recessive genetic mutation, designated gene c, for cardiac nonfunction. The double recessive mutants (c/c) fail to form organized myofibrils in the cardiac myoblasts resulting in hearts that fail to beat. Tropomyosin expression patterns have been studied in detail and show dramatically decreased expression in the hearts of homozygous mutant embryos. Because of the direct interaction between tropomyosin and troponin T (TnT), and the crucial functions of TnT in the regulation of striated muscle contraction, we have expanded our studies on this animal model to characterize the expression of the TnT gene in cardiac muscle throughout normal axolotl development as well as in mutant axolotls. In addition, we have succeeded in cloning the full-length cardiac troponin T (cTnT) cDNA from axolotl hearts. Confocal microscopy has shown a substantial, but reduced, expression of TnT protein in the mutant hearts when compared to normal during embryonic development.

show abstract

A Specific Synthetic RNA Promotes Cardiac Myofibrillogenesis in the Mexican Axolotl

Cited by 24 publications

References 0 publications

Characterization of a TM‐4 type tropomyosin that is essential for myofibrillogenesis and contractile activity in embryonic hearts of the Mexican axolotl*

Characterization of a TM‐4 type tropomyosin that is essential for myofibrillogenesis and contractile activity in embryonic hearts of the Mexican axolotl*

A point mutation in bioactive RNA results in the failure of mutant heart correction in mexican axolotls

Molecular and immunohistochemical analyses of cardiac troponin T during cardiac development in the Mexican axolotl, Ambystoma mexicanum

Contact Info

Product

Resources

About