The UCS factor Steif/Unc-45b interacts with the heat shock protein Hsp90a during myofibrillogenesis

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2007.05.014 Byline: Christelle Etard (a)(b), Martine Behra (a)(d), Nadine Fischer (a), David Hutcheson (b), Robert Geisler (c), Uwe Strahle (a)(b) Keywords: Zebrafish; Chaperone; Co-chaperone; Muscle damage; hsp90a; UCS factor Abstract: Contraction of muscles is mediated by highly organized arrays of myosin motor proteins. We report here the characterization of a mutation of a UCS gene named steif/unc-45b that is required for the formation of ordered myofibrils in both the skeletal and cardiac muscles of zebrafish. We show that Steif/Unc-45b interacts with the chaperone Hsp90a in vitro. The two genes are co-expressed in the skeletal musculature and knockdown of Hsp90a leads to impaired myofibril formation in the same manner as lack of Steif/Unc-45b activity. Transcripts of both genes are up-regulated in steif mutants suggesting co-regulation of the two genes. Our data indicate a requirement of Steif/unc-45b and Hsp90a for the assembly of the contractile apparatus in the vertebrate skeletal musculature. Author Affiliation: (a) Institut de Genetique et de Biologie Moleculaire et Cellulaire, 1 rue Laurent Fries, 67404 Illkirch Cedex, CU de Strasbourg, France (b) Institute for Toxicology and Genetics, Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe, Germany (c) Max-Planck-Institut fur Entwicklungsbiologie, Spemannstr 35, D-72076 Tubingen, Germany (d) NIH/NHGRI Building 50, Bethesda, Maryland, USA Article History: Received 2 March 2007; Revised 9 May 2007; Accepted 15 May 2007