A developmental and tissue-specific enhancer in the mouse skeletal muscle acetylcholine receptor alpha-subunit gene regulated by myogenic factors.
The expression of the nicotinic acetylcholine receptor (AChR) in vertebrate striated muscle is regulated both during development and in response to nerve-evoked muscle activity. To define DNA sequences necessary for the transcriptional regulation of the mouse alpha-subunit AChR gene, we have isolated and analyzed the alpha-gene 5'-flanking region. Primer extension and RNase protection analysis showed that transcription initiates at 2 major and 12 minor sites close to the translational initiation site. Using a series of plasmids in which segments of the 5'-flanking region were linked to the bacterial chloramphenicol acetyltransferase (CAT) gene, we have defined an 86-base pair enhancer sequence that is active in C2 myotubes but not in C2 myoblasts or NIH3T3 fibroblasts. This enhancer contains three putative binding sites for myoD1, and the 5'-upstream regions linked to CAT were transactivated by the muscle regulatory factors, myoD1, and myogenin. Transactivation by MRF4 differed with the specific alpha-subunit construct tested. Whereas the alpha-subunit CAT constructs containing both the homologous as well as the heterologous myosin light chain 1 promoter were transactivated by myoD1 and myogenin, only the constructs containing their homologous promoter were transactivated by MRF4. Thus, an 86-base pair sequence of the alpha-subunit gene contains the information necessary for developmental specificity and responsiveness to myogenic factors.
Prody
C A
CA
Department of Molecular Biology and Pharmacology, Washington University Medical School, St. Louis, Missouri 63110.
Merlie
J P
JP
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002645:Chickens; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D046911:Macromolecular Substances; D051379:Mice; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000502:physiology*; D009132:Muscles / Q000502:physiology*; D017570:MyoD Protein; D018008:Myogenin; D009687:Nuclear Proteins / Q000502:physiology*; D010750:Phosphoproteins / Q000502:physiology*; D011950:Receptors, Cholinergic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators / Q000502:physiology*; D015533:Transcriptional Activation; D014162:Transfection
D046911:Macromolecular Substances; D009124:Muscle Proteins; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; C503801:Myog protein, mouse; D018008:Myogenin; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011950:Receptors, Cholinergic; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D015500:Chloramphenicol O-Acetyltransferase