Functional analysis of Smyd1 and Myomesin in sarcomere organization in zebrafish embryos

Abstract

Myofibrillogenesis, the process of sarcomere formation, requires close interaction of sarcomeric proteins and molecular chaperones. Smyd1 is a lysine methyltransferase that plays important roles in myofibrillogenesis in both skeletal and cardiac muscles. Knockdown of smyd1 results in complete disruption of sarcomere organization. The molecular mechanism by which Smyd1 controls myofibril assembly is not clear. In this study, we analyzed the sub-cellular localization of Smyd1, the effect of smyd1 knockdown on protein methylation, and the effect of myomesin knockdown on sarcomere organization. We demonstrated that Smyd1b_tv1 is localized to the M-lines of skeletal muscles in zebrafish embryos. Knockdown of myomesin-1b or myomesin-3 had no effect on the sarcomere organization. Western blot analysis revealed that knockdown of smyd1 reduced the overall protein methylation in zebrafish embryos. Together, these studies indicate that Smyd1 is required for M-line organization and Smyd1 may play a role in protein methylation and is involved in sarcomere assembly.