Functional Analysis of Slow Myosin Heavy Chain 1 and Myomesin-3 in Sarcomere Organization in Zebrafish Embryonic Slow Muscles  

作　　者：Jin Xu Jie Gao Junling Li Liangyi Xue Kan J. Clark Stephen C. Ekker Shao Jun Du 

机构地区：[1]Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21202, USA [2]College of Life Science and Biotechnology, Ningbo University, Ningbo 315211, Zhejiang, China [3]Department of Biochemistry ＆ Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA

出　　处：《Journal of Genetics and Genomics》2012年第2期69-80,共12页遗传学报（英文版）

基　　金：supported by a research grant(MB-8716-08) from United States-Israel Binational Agriculture Research and Development Fund to SJD and a NIH grant(DA14546) to SCE;Liangyi Xue was supported by a Pao Yu-Kong and Pao Zhao-Long Scholarship for Chinese Scholars Studying Abroad from Ningbo University,China

摘　　要：Myofibrillogenesis, the process of sarcomere formation, requires close interactions of sarcomeric proteins and various components of sarcomere structures. The myosin thick filaments and M-lines are two key components of the sarcomere. It has been suggested that myomesin proteins of M-lines interact with myosin and titin proteins and keep the thick and titin filaments in order. However, the function of myomesin in myofibrillogenesis and sarcomere organization remained largely enigmatic. No knockout or knockdown animal models have been reported to elucidate the role of myomesin in sarcomere organization in vivo. In this study, by using the gene-specific knockdown approach in zebrafish embryos, we carded out a loss-of-function analysis of myomesin-3 and slow myosin heavy chain 1 （smyhcl） expressed specifically in slow muscles. We demonstrated that knockdown of smyhcl abolished the sarcomeric localization of myomesin-3 in slow muscles. In contrast, loss of myomesin-3 had no effect on the sarcomeric organization of thick and thin filaments as well as M- and Z-line structures. Together, these studies indicate that myosin thick filaments are required for M-line organization and M-line localization of myomesin-3. In contrast, myomesin-3 is dispensable for sarcomere organization in slow muscles.Myofibrillogenesis, the process of sarcomere formation, requires close interactions of sarcomeric proteins and various components of sarcomere structures. The myosin thick filaments and M-lines are two key components of the sarcomere. It has been suggested that myomesin proteins of M-lines interact with myosin and titin proteins and keep the thick and titin filaments in order. However, the function of myomesin in myofibrillogenesis and sarcomere organization remained largely enigmatic. No knockout or knockdown animal models have been reported to elucidate the role of myomesin in sarcomere organization in vivo. In this study, by using the gene-specific knockdown approach in zebrafish embryos, we carded out a loss-of-function analysis of myomesin-3 and slow myosin heavy chain 1 （smyhcl） expressed specifically in slow muscles. We demonstrated that knockdown of smyhcl abolished the sarcomeric localization of myomesin-3 in slow muscles. In contrast, loss of myomesin-3 had no effect on the sarcomeric organization of thick and thin filaments as well as M- and Z-line structures. Together, these studies indicate that myosin thick filaments are required for M-line organization and M-line localization of myomesin-3. In contrast, myomesin-3 is dispensable for sarcomere organization in slow muscles.

关 键 词：MYOSIN Myomesin-3 M-LINE SARCOMERE 

分 类 号：S945.26[农业科学—水产养殖] TS251.7[农业科学—水产科学]