Regulation of murine cytochrome oxidase Vb gene expression in different tissues and during myogenesis. Role of a YY-1 factor-binding negative enhancer.
The mouse cytochrome oxidase (COX) Vb promoter contains three sequence motifs with partial or full consensus for YY-1 and GTG factor binding and a CArG box, located between positions -480 and -390. Individually, all three motifs stimulated transcription of the TKCAT promoter, and bound distinctly different proteins from the liver and differentiated C2C12 nuclear extracts. Collectively, these motifs, together with the downstream flanking sequence, -378 to -320, suppressed the transcription activity of heterologous promoters, thymidine kinase-chloramphenicol acetyltransferase (TKCAT) and COXIV/CAT. The transcription activities of both TKCAT and COXIV/CAT constructs were induced 3-4-fold during induced myogenesis of C2C12 cells. The downstream CArG-like motif binds transcription factor YY-1, while the upstream YY-1-like motif binds to a yet unidentified factor. Co-expression with intact YY-1, but not that lacking the DNA binding domain suppressed the transcriptional activity. Mutations targeted to the CArG-like motif abolished the suppressive effect of the negative enhancer and the inducibility of the promoter during myogenic differentiation. Our results suggest that the activity of the negative enhancer may determine the level of expression of the COX Vb gene in different tissues.
Basu
A
A
Laboratories of Biochemistry, Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6047, USA.
Lenka
N
N
Mullick
J
J
Avadhani
N G
NG
D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003402:Creatine Kinase / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D050981:Erythroid-Specific DNA-Binding Factors; D015971:Gene Expression Regulation, Enzymologic; D005809:Genes, Regulator; D051379:Mice; D008969:Molecular Sequence Data; D024510:Muscle Development; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D014157:Transcription Factors; D003576:Electron Transport Complex IV; D003402:Creatine Kinase