ZFIN ID: ZDB-PUB-080209-1
Heat-shock protein 90alpha1 is required for organized myofibril assembly in skeletal muscles of zebrafish embryos
Du, S.J., Li, H., Bian, Y., and Zhong, Y.
Date: 2008
Source: Proc. Natl. Acad. Sci. USA 105(2): 554-559 (Journal)
Registered Authors: Du, Shao Jun (Jim)
Keywords: myofibrillogenesis, unc45, myosin chaperone, Hsp90
MeSH Terms: Amino Acid Sequence; Animals; Base Sequence; Gene Expression Regulation, Developmental*; HSP90 Heat-Shock Proteins/chemistry* (all 16) expand
PubMed: 18182494 Full text @ Proc. Natl. Acad. Sci. USA
FIGURES   (current status)
Heat-shock protein 90alpha (Hsp90alpha) is a member of the molecular chaperone family involved in protein folding and assembly. The role of Hsp90alpha in the developmental process, however, remains unclear. Here we report that zebrafish contains two Hsp90alpha genes, Hsp90alpha1, and Hsp90alpha2. Hsp90alpha1 is specifically expressed in developing somites and skeletal muscles of zebrafish embryos. We have demonstrated that Hsp90alpha1 is essential for myofibril organization in skeletal muscles of zebrafish embryos. Knockdown of Hsp90alpha1 resulted in paralyzed zebrafish embryos with poorly organized myofibrils in skeletal muscles. In contrast, knockdown of Hsp90alpha2 had no effect on muscle contraction and myofibril organization. The filament defects could be rescued in a cell autonomous manner by an ectopic expression of Hsp90alpha1. Biochemical analyses revealed that knockdown of Hsp90alpha1 resulted in significant myosin degradation and up-regulation of unc-45b gene expression. These results indicate that Hsp90alpha1 plays an important role in muscle development, likely through facilitating myosin folding and assembly into organized myofibril filaments.