Smyd1b is required for skeletal and cardiac muscle function in zebrafish.
Smyd1b is a member of the Smyd family that is specifically expressed in skeletal and cardiac muscles. Smyd1b plays a key role in thick filament assembly during myofibrillogenesis in skeletal muscles of zebrafish embryos. To better characterize Smyd1b function and its mechanism of action in myofibrillogenesis, we analyzed the effects of smyd1b knockdown on myofibrillogenesis in skeletal and cardiac muscles of zebrafish embryos. The results show that knockdown of smyd1b causes significant disruption of myofibril organization in both skeletal and cardiac muscles of zebrafish embryos. Microarray and quantitative reverse transcription-PCR analyses show that knockdown of smyd1b up-regulates heat shock protein 90 (hsp90) and unc45b gene expression. Biochemical analysis reveals that Smyd1b can be coimmunoprecipitated with heat shock protein 90 α-1 and Unc45b, two myosin chaperones expressed in muscle cells. Consistent with its potential function in myosin folding and assembly, knockdown of smyd1b significantly reduces myosin protein accumulation without affecting mRNA expression. This likely results from increased myosin degradation involving unc45b overexpression. Together these data support the idea that Smyd1b may work together with myosin chaperones to control myosin folding, degradation, and assembly into sarcomeres during myofibrillogenesis.
Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21202 Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201 Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20892 Department of Bioengineering and Environmental Science, Changsha University, Hunan 410003, China.
Huiqing
H
Li
Yongwang
Y
Zhong
Zengfeng
Z
Wang
Jie
J
Gao
Jin
J
Xu
Wuying
W
Chu
Jianshe
J
Zhang
Shenyun
S
Fang
Shao Jun
SJ
Du
D000818:Animals; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D011495:Histone-Lysine N-Methyltransferase / Q000172:deficiency / Q000235:genetics*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D024510:Muscle Development / Q000235:genetics; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D009206:Myocardium / Q000378:metabolism* / Q000648:ultrastructure; D009218:Myosins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D055550:Protein Stability; D059748:Proteolysis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D015027:Zebrafish / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029961:Zebrafish Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism
D018841:HSP90 Heat-Shock Proteins; D018832:Molecular Chaperones; D009124:Muscle Proteins; D012333:RNA, Messenger; C472790:Unc45b protein, zebrafish; D029961:Zebrafish Proteins; D011495:Histone-Lysine N-Methyltransferase; C510871:SmyD1a protein, zebrafish; D009218:Myosins