The UCS factor Steif/Unc-45b interacts with the heat shock protein Hsp90a during myofibrillogenesis.
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.
Etard
Christelle
C
Institut de Génétique et de Biologie Moléculaire et Cellulaire, 1 rue Laurent Fries, 67404 Illkirch Cedex, CU de Strasbourg, France.
Behra
Martine
M
Fischer
Nadine
N
Hutcheson
David
D
Geisler
Robert
R
Strähle
Uwe
U
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006321:Heart / Q000196:embryology; D066298:In Vitro Techniques; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D024510:Muscle Development / Q000235:genetics / Q000502:physiology*; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000196:embryology / Q000378:metabolism / Q000648:ultrastructure; D009154:Mutation; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure; D010641:Phenotype; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
D018841:HSP90 Heat-Shock Proteins; D009124:Muscle Proteins; C472790:Unc45b protein, zebrafish; D029961:Zebrafish Proteins; D004247:DNA