Anti-sense-mediated inhibition of expression of the novel striated tropomyosin isoform TPM1kappa disrupts myofibril organization in embryonic axolotl hearts

• Published in: Journal of cellular biochemistry Vol. 95; no. 4; pp. 840 - 848
• Main Authors: Zajdel, Robert W, Denz, Christopher R, Narshi, Aruna, Dube, Syamalima, Dube, Dipak K
• Format: Journal Article
• Language: English
• Published: United States 01.07.2005
• Subjects: Ambystoma - embryology; Animals; Heart - embryology; Microscopy, Confocal; Myocardium - metabolism; Myofibrils - chemistry; Myofibrils - metabolism; Oligonucleotides, Antisense - genetics; Oligonucleotides, Antisense - metabolism; Protein Isoforms - genetics; Protein Isoforms - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; Tropomyosin - genetics; Tropomyosin - metabolism
• ISSN: 0730-2312

Striated muscle tropomyosin (TM) is described as containing ten exons; 1a, 2b, 3, 4, 5, 6b, 7, 8, and 9a/b. Exon 9a/b has critical troponin binding domains and is found in striated muscle isoforms. We have recently discovered a smooth (exon 2a)/striated (exons 9a/b) isoform expressed in amphibian, avian, and mammalian hearts, designated as an isoform of the TPM1 gene (TPM1kappa). TPM1kappa expression was blocked in whole embryonic axolotl heart by transfection of exon-specific anti-sense oligonucleotide. Reverse transcriptase polymerase chain reaction (RT-PCR) confirmed lower transcript expression of TPM1kappa and in vitro analysis confirmed the specificity of the TPM1kappa anti-sense oligonucleotide. Altered expression of the novel TM isoform disrupted myofibril structure and function in embryonic hearts.