Morphological Modifications in Myofibrils by Suppressing Tropomyosin 4α in Chicken Cardiac Myocytes

Cell Structure and Function

Naoji Toyota¹  Goushi Ishibashi¹  Chiaki Fujitsuka¹  Lucia S. Yoshida²  Hiromi Takano-Ohmuro² 

[1] Department of Environmental Biology, Kumamoto Gakuen University;Research Institute of Pharmaceutical Sciences, Musashino University

关键词: myofibril;    primary culture;    RNAi;    actin filament;   

DOI  :  10.1247/csf.15007

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

References(39)Tropomyosin (TPM) localizes along F-actin and, together with troponin T (TnT) and other components, controls calcium-sensitive muscle contraction. The role of the TPM isoform (TPM4α) that is expressed in embryonic and adult cardiac muscle cells in chicken is poorly understood. To analyze the function of TPM4α in myofibrils, the effects of TPM4α-suppression were examined in embryonic cardiomyocytes by small interference RNA transfection. Localization of myofibril proteins such as TPM, actin, TnT, α-actinin, myosin and connectin was examined by immunofluorescence microscopy on day 5 when almost complete TPM4α-suppression occurred in culture. A unique large structure was detected, consisting of an actin aggregate bulging from the actin bundle, and many curved filaments projecting from the aggregate. TPM, TnT and actin were detected on the large structure, but myosin, connectin, α-actinin and obvious myofibril striations were undetectable. It is possible that TPM4α-suppressed actin filaments are sorted and excluded at the place of the large structure. This suggests that TPM4α-suppression significantly affects actin filament, and that TPM4α plays an important role in constructing and maintaining sarcomeres and myofibrils in cardiac muscle.

【 授权许可】

Unknown