title: cis-acting elements responsible for muscle-specific expression of the myosin heavy chain beta gene.
abstract: The 5' flanking region of the rabbit myosin heavy chain (HC) beta gene extending 295 bp upstream from the cap site provides muscle-specific transcriptional activity. In this study, we have identified and functionally characterized cis-acting elements that regulate the muscle-specific expression within this region. By using linker-scanner (LS) mutants between -295 bp and a putative TATA box, we found five distinct positive cis-acting sequences necessary for transcription: element A, the sequences between -276 and -263, which contains a putative M-CAT motif in an inverted orientation; B, the sequences between -207 and -180; C, the sequences between -136 and -127; D, the sequences between -91 and -80; and E, a TATA consensus sequence at -28. The fragment containing both A and B elements dramatically enhanced the expression of the chloramphenicol acetyltransferase (CAT) gene driven by a heterologous promoter in differentiated muscle cells, whereas fragments containing either A or B elements alone had little or no effect in either muscle or nonmuscle cells. Therefore, these two elements appear to act cooperatively in determining a high level of muscle- and stage-specific expression. Unlike the typical enhancer element, this region functions in an orientation-dependent manner. In contrast, the fragment containing C and D elements activates the heterologous promoter in both muscle and nonmuscle cells in an orientation-independent manner.
authors.affiliation: Department of Medicine, University of Chicago, IL 60637.
authors.forename: N
authors.initials: N
authors.lastname: Shimizu
authors.forename: G
authors.initials: G
authors.lastname: Prior
authors.forename: P K
authors.initials: PK
authors.lastname: Umeda
authors.forename: R
authors.initials: R
authors.lastname: Zak
mesh_terms: D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002642:Chick Embryo; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics; D008969:Molecular Sequence Data; D009132:Muscles / Q000737:chemistry; D016296:Mutagenesis / Q000235:genetics; D009218:Myosins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*
chemical_list: D011993:Recombinant Fusion Proteins; D015500:Chloramphenicol O-Acetyltransferase; D009218:Myosins