The role of the CANNTG promoter element (E box) and the myocyte-enhancer-binding-factor-2 (MEF-2) site in the transcriptional regulation of the chick myogenin gene.
We have carried out an analysis of 833 bp of the chick myogenin gene 5' flanking sequence. A 131-bp segment of this upstream region, which contains a CANNTG promoter element (E box) and a myocyte-enhancer-binding-factor-2 (MEF-2) site, acts as a full promoter. It resembles the human and the mouse myogenin promoters in the structure and disposition of regulatory elements, including a TATA box and the transcription start site. Examination of eight myogenic factor/E protein combinations cotransfected with several myogenin promoter constructs into HeLa cells, reveals that the chick myogenin/E2-5 combination maximally activates the myogenin promoter. This activation is mediated through the E box motif; the MEF-2 site limits the factor combinations that can activate the myogenin promoter and enhances activation by myogenin/E2-5. We have found previously that activation of protein kinase C inactivates the transcription of the chick myogenin gene [Huang, C.-F., Neville, C. M. & Schmidt, J. (1993) Control of myogenic factor genes by the membrane depolarization/protein kinase C cascade in chick skeletal muscle, FEBS Lett. 319, 21-25]. In this study, we show that the activation of protein kinase C inhibits the factor bound to the E box, which thereupon negatively regulates the activity of the MEF-2 binding protein.
Malik
S
S
Department of Biochemistry and Cell Biology, State University of New York at Stony Brook 11794, USA.
Huang
C F
CF
Schmidt
J
J
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002645:Chickens; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D064326:MEF2 Transcription Factors; D008969:Molecular Sequence Data; D018006:Myogenic Regulatory Factors; D018008:Myogenin / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D064326:MEF2 Transcription Factors; C503799:MYOG protein, human; D018006:Myogenic Regulatory Factors; D018008:Myogenin; D014157:Transcription Factors; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate