In vitro translation of RNA from embryonic and from adult chicken pectoralis muscle produces different myosin heavy chains

Abstract

A unique myosin heavy chain exists in embryonic fast muscle of the rat [ 11, rabbit [2,3] and chicken [4]. Other studies of embryonic rabbit fast myosin found the absence of a methylated sequence which is present in adult fast muscle myosin [5]. This methylation was shown to be a post-translational modification of the heavy chain [2,6]. Since differences between embryonic and adult myosin heavy chain are small [ 1,4,7], it is possible that the embryonic myosin heavy chain is not a unique gene product. striated and exhibited spontaneous contractions by the procedure in [lo]. Myosins were also prepared from the pectoralis muscle of 15 day chick embryos and the pectoralis muscle and the anterior latissimus dorsi muscle of adult chickens by identical procedures. Ail chickens and eggs were of the white Leghorn variety. Myosin preparations were stored in 40 mM sodium pyrophosphate, 50% glycerol at -20°C.