A REPRESSOR REGION IN THE HUMAN BETA-MYOSIN HEAVY-CHAIN GENE THAT HAS A PARTIAL POSITION DEPENDENCY

Expression of the human β-myosin heavy chain (βMHC) gene was studied by transient assay in culture and in situ by direct injection of plasmids into adult rat hearts. In this report we describe a unique repressor region located -326/-309 (5′-TTGGTGGTCGTGGTCAGT-3′) of the human βMHC gene that is conserved among the rat, rabbit, and human βMHC genes. This sequence conferred repression onto heterologous promoters when the sequence was located 5′ but not 3′ to the promoters. This partial positional dependency suggests that the factor may act by limiting the binding of enhancers, located more proximally, to their DNA binding sites. © 1992.