Partial characterization of the human β‐myosin heavy‐chain gene which is expressed in heart and skeletal muscle

Abstract

A human myosin heavy‐chain gene, cloned in γCharon 4A phage (and as a clone designated γgMHC‐1), was shown to code for a cardiac myosin heavy chain of the β‐type. The 5′ end of the 14200‐base‐pair genomic DNA clone is located in the head region of the myosin chain. The 3′ end was shown to extent to the COOH terminus and includes the 3′‐nontranslated sequence of the corresponding mRNA. The identification of γgMHC‐1 as coding for a cardiac β‐myosin heavy chain was achieved by heteroduplex mapping using genomic cardiac myosin heavy‐chain DNA of rabbit as a probe and, furthermore, by DNA sequence analysis of three selected subregions of the cloned DNA including the 3′‐nontranslated sequence. It was demonstrated by the S1 nuclease protection technique that the β‐myosin heavy‐chain gene is transcribed in human heart muscle. In addition, we have found by the same technique that it is also expressed in human skeletal muscle.