Qualitative and quantitative evaluation of TPM transcripts and proteins in developing striated chicken muscles indicate TPM4? is the major sarcomeric cardiac tropomyosin from early embryonic life to adulthood.

ABSTRACT: The chicken has been used since the 1980s as an animal model for developmental studies regarding tropomyosin isoform diversity in striated muscles, however, the pattern of expression of transcripts as well as the corresponding TPM proteins of various tropomyosin isoforms in avian hearts are not well documented. In this study, using conventional and qRT-PCR, we report the expression of transcripts for various sarcomeric TPM isoforms in striated muscles through development. Transcripts of both TPM1? and TPM1?, the two sarcomeric isoforms of the TPM1 gene, are expressed in embryonic chicken hearts but disappear in post hatch stages. TPM1? transcripts are expressed in embryonic and adult skeletal muscle. The sarcomeric isoform of the TPM2 gene is expressed mostly in embryonic skeletal muscles. As reported earlier, TPM3? is expressed in embryonic heart and skeletal muscle but significantly lower in adult striated muscle. TPM4? transcripts are expressed from embryonic to adult chicken hearts but not in skeletal muscle. Our 2D Western blot analyses using CH1 monoclonal antibody followed by mass spectra evaluations found TPM4? protein is the major sarcomeric tropomysin expressed in embryonic chicken hearts. However, in 7-day-old embryonic hearts, a minute quantity of TPM1? or TPM1? is also expressed. This finding suggests that sarcomeric TPM1 protein may play some important role in cardiac contractility and/or cardiac morphogenesis during embryogenesis. Since only the transcripts of TPM4? are expressed in adult chicken hearts, it is logical to presume that TPM4? is the only sarcomeric TPM protein produced in adult cardiac tissues.

SUBMITTER: Dube DK 

PROVIDER: S-EPMC6279486 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature