Poly(ADP-ribose) polymerase binds with transcription enhancer factor 1 to MCAT1 elements to regulate muscle-specific transcription.
Striated muscle-specific expression of the cardiac troponin T (cTNT) gene is mediated through two MCAT elements that act via binding of transcription enhancer factor 1 (TEF-1) to the MCAT core motifs and binding of an auxiliary protein to nucleotides flanking the 5' side of the core motif. Using DNA-protein and protein-protein binding experiments, we identified a 140-kDa polypeptide that bound both the muscle-specific flanking sequences of the most distal MCAT1 element and TEF-1. Screening of an expression library with the MCAT1 element yielded a cDNA encoding a truncated form of poly(ADP-ribose) polymerase (PARP). Endogenous PARP from embryonic tissue nuclear extracts migrated as a 140-kDa protein. Recombinant full-length PARP preferentially bound the wild-type MCAT1 element and was shown to physically interact with TEF-1. In addition, endogenous TEF-1 could be coimmunoprecipitated with PARP from extracts of primary skeletal muscle cells. Recombinant PARP was able to ADP-ribosylate TEF-1 in vitro. Inhibition of the enzymatic activity of PARP repressed expression of an MCAT1-dependent reporter in transiently transfected primary muscle cells. Together, these data implicate PARP as the auxiliary protein that binds with TEF-1 to the MCAT1 element to provide muscle-specific gene transcription.
Butler
A J
AJ
Department of Anatomy and Cardiovascular Research Institute, University of California San Francisco, San Francisco, California 94143-0452, USA.
Ordahl
C P
CP
D026923:Amino Acid Transport Systems, Basic; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002642:Chick Embryo; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D008565:Membrane Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal; D009687:Nuclear Proteins; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D012266:Ribose / Q000378:metabolism; D000091262:TEA Domain Transcription Factors; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D026923:Amino Acid Transport Systems, Basic; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D000091262:TEA Domain Transcription Factors; C057182:TEAD1 protein, human; D014157:Transcription Factors; D012266:Ribose; D011065:Poly(ADP-ribose) Polymerases