Expression of a novel tropomyosin isoform in axolotl heart and skeletal muscle.

TPM1kappa is an alternatively spliced isoform of the TPM1 gene whose specific role in cardiac development and disease is yet to be elucidated. Although mRNA studies have shown TPM1kappa expression in axolotl heart and skeletal muscle, it has not been quantified. Also the presence of TPM1kappa protein in axolotl heart and skeletal muscle has not been demonstrated. In this study, we quantified TPM1kappa mRNA expression in axolotl heart and skeletal muscle. Using a newly developed TPM1kappa specific antibody, we demonstrated the expression and incorporation of TPM1kappa protein in myofibrils of axolotl heart and skeletal muscle. The results support the potential role of TPM1kappa in myofibrillogenesis and sarcomeric function.