title: Two adjacent E box elements and a M-CAT box are involved in the muscle-specific regulation of the rat acetylcholine receptor beta subunit gene.
abstract: We have isolated and analysed the 5' flanking region of the rat acetylcholine receptor (AChR) beta subunit gene and determined regulatory elements that confer muscle specificity. Deletion mapping revealed a minimal TATA-box-less promoter region containing an initiator motif. An 85-bp fragment has been shown to promote high muscle-specific expression of a chloramphenicol acetyltransferase (CAT) reporter construct upon transfection in primary muscle cells. This sequence can be functionally dissected in a basal muscle-specific promoter element carrying a M-CAT box that is flanked at the 5' end by an enhancer element with two binding sites for myogenic factors. Point mutations in the M-CAT box cause the loss of transcriptional activity of the basal promoter fragment. The enhancer activity depends on the presence of both E boxes that cooperate in a synergistic fashion. We therefore conclude that the control of muscle-specific and developmental expression of the rat AChR beta subunit gene requires both regulatory elements, the M-CAT box and two adjacent E boxes, located in close proximity to each other. Cotransfection experiments in NIH3T3 cells demonstrate that the rat AChR beta subunit gene can be transactivated by myogenic factors displaying a preference for myogenin, as well as MRF4 and myf5 compared to a clearly weaker responsiveness to MyoD1.
authors.affiliation: Max-Planck-Institut für medizinische Forschung, Abteilung Zellphysiologie, Heidelberg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Berberich
authors.forename: I
authors.initials: I
authors.lastname: Dürr
authors.forename: M
authors.initials: M
authors.lastname: Koenen
authors.forename: V
authors.initials: V
authors.lastname: Witzemann
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D004247:DNA; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics; D009132:Muscles / Q000378:metabolism*; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D051381:Rats; D011978:Receptors, Nicotinic / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D017384:Sequence Deletion; D015533:Transcriptional Activation
chemical_list: D009124:Muscle Proteins; D011978:Receptors, Nicotinic; D004247:DNA