Knockdown of Unc-45b or Hsp90α1 results in significant reduction of myosin and α-actin accumulation. Western blot was performed using protein extracts from Unc-45b or Hsp90α1 knockdown, or uninjected control embryos at 24, 48 and 72 hpf using anti-myosin antibodies F59 (A) and MF20 (B) that recognize slow muscle myosin or general myosin proteins, respectively. The data show decreased levels of slow or total myosin proteins in Unc-45b and Hsp90α1 knockdown embryos at 24 and 48 hpf. A partial recovery of myosin expression was noted in 72 hpf embryos. Decreased levels of α-actin were also detected in the Unc-45b and Hsp90α1 knockdown embryos at 48 and 72 hpf. γ-tublin was used as loading control. Protein extract from five embryos each was used at 24 hpf. Protein extracts from three embryos were used at 48 and 72 hpf.