Impact of α-Skeletal Actin but not α-Cardiac Actin on Myoblast Morphology

Cell Structure and Function

Karen Brennan²  Peter Gunning¹  Edna Hardeman²  Vicki Ferguson¹ 

[1] CellBiology Unit, Children's Medical Research Institute;Muscle Development Unit, Children's Medical Research Institute

关键词: Actin;    Isoforms;    Cytoarchitecture;    Muscle;    Transfection;   

DOI  :  10.1247/csf.22.173

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(33)Cited-By(2)Muscle differentiation involves a profound change in cell cytoarchitecture. This is accompanied by extensive isoform replacement in which the major non-muscle isoforms of the actin filament system are replaced by their muscle isoform counterparts. We have tested whether the sequential expression of the actin isoforms is functionally significant by precociously expressing the two striated muscle actins (α-skeletal and α-cardiac) in mouse myoblasts. The human α-skeletal and α-cardiac actin genes were transfected into mouse C2 myoblasts and clones expressing the human genes at the highest level were identified. Expression of the human α-skeletal actin gene was low with the highest mRNA level found to be 4% of that in adult human skeletal muscle. Clones expressing α-cardiac actin accumulated the mRNA up to 13% of the level of α-skeletal actin in adult human skeletal muscle. Despite the low level of α-skeletal actin expression, myoblasts transfected with this gene displayed a profound decrease in cell spreading. In contrast, α-cardiac actin had no impact on cell spreading. Neither α-skeletal actin nor α-cardiac actin had any impact on the total actin protein pool nor on the levels of the high molecular weight tropomyosins. The organisation of actin and tropomyosin into stress fibres was similar between transfected and control cells. We conclude that precocious expression of α-skeletal actin, but not acardiac actin, compromises myoblast morphology but not the ability of the cell to assemble stress-fibre-like structures.

【 授权许可】

Unknown