title: Transcriptional regulation of acetylcholinesterase-associated collagen ColQ: differential expression in fast and slow twitch muscle fibers is driven by distinct promoters.
abstract: The presence of a collagenous protein (ColQ) characterizes the collagen-tailed forms of acetylcholinesterase and butyrylcholinesterase at vertebrate neuromuscular junctions which is tethered in the synaptic basal lamina. ColQ subunits, differing mostly by their signal sequences, are encoded by transcripts ColQ-1 and ColQ-1a, which are differentially expressed in slow and fast twitch muscles in mammals. Two distinct promoters, pColQ-1 and pColQ-1a, were isolated from the upstream sequences of human COLQ gene; they showed muscle-specific expression and were activated by myogenic transcriptional elements in cultured myotubes. After in vivo DNA transfection, pColQ-1 showed strong activity in slow twitch muscle (e.g. soleus), whereas pColQ-1a was preferably expressed in fast twitch muscle (e.g. tibialis). Mutation analysis of the ColQ promoters suggested that the muscle fiber type-specific expression pattern of ColQ transcripts were regulated by a slow upsteam regulatory element (SURE) and a fast intronic regulatory element (FIRE). These regulatory elements were responsive to a calcium ionophore and to calcineurin inhibition by cyclosporine A. The slow fiber type-specific expression of ColQ-1 was abolished by the mutation of an NFAT element in pColQ-1. Moreover, both the ColQ promoters contained N-box element that was responsible for the synapse-specific expression of ColQ transcripts. These results explain the specific expression patterns of collagen-tailed acetylcholinesterase in slow and fast muscle fibers.
authors.affiliation: Department of Biology, Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong SAR, China.
authors.forename: Henry H C
authors.initials: HH
authors.lastname: Lee
authors.forename: Roy C Y
authors.initials: RC
authors.lastname: Choi
authors.forename: Annie K L
authors.initials: AK
authors.lastname: Ting
authors.forename: Nina L
authors.initials: NL
authors.lastname: Siow
authors.forename: Joy X S
authors.initials: JX
authors.lastname: Jiang
authors.forename: Jean
authors.initials: J
authors.lastname: Massoulié
authors.forename: Karl W K
authors.initials: KW
authors.lastname: Tsim
mesh_terms: D000110:Acetylcholinesterase / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002460:Cell Line; D002645:Chickens; D003094:Collagen / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005091:Exons / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D018656:Muscle Fibers, Fast-Twitch / Q000201:enzymology / Q000378:metabolism*; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D018657:Muscle Fibers, Slow-Twitch / Q000201:enzymology / Q000378:metabolism*; D009124:Muscle Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism; D050778:NFATC Transcription Factors; D020880:Neuregulins / Q000494:pharmacology; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid; D009435:Synaptic Transmission / Q000187:drug effects; D013873:Thionucleotides / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D014162:Transfection
chemical_list: D004268:DNA-Binding Proteins; D009124:Muscle Proteins; D050778:NFATC Transcription Factors; D020880:Neuregulins; D009687:Nuclear Proteins; D013873:Thionucleotides; D014157:Transcription Factors; C002480:methylthio-ADP; D000244:Adenosine Diphosphate; D003094:Collagen; D000110:Acetylcholinesterase; C114027:COLQ protein, human