Expression of the Human Cytochrome c1 Gene is Controlled through Multiple Sp1-Binding Sites and an Initiator Region
| Autor: | Ronggui Li, B. Dean Nelson, Katarina Luciakova |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Molecular Sequence Data
Response element Gene Expression Cytochromes c1 Biology Transfection Polymerase Chain Reaction Biochemistry Oxidative Phosphorylation Primer extension Cell Line Mice Cytochrome C1 Gene expression Transcriptional regulation Animals Humans Peptide Chain Initiation Translational Promoter Regions Genetic Gene DNA Primers Podophyllotoxin Sp1 transcription factor Binding Sites Podophyllin Base Sequence Promoter 3T3 Cells Molecular biology |
| Zdroj: | European Journal of Biochemistry. 241:649-656 |
| ISSN: | 1432-1033 0014-2956 |
| Popis: | It is widely accepted that nuclear genes that encode proteins of the oxidative-phosphorylation system are regulated by nuclear factors believed to be specific for such genes. In the present study we show that the promoter for the human cytochrome c1 gene is an exception, in that it involves only conserved Sp1 core elements and an initiator region. Maximal promoter activity within a 1.4-kb 5' flanking region of the cytochrome c1 gene is contained in a fragment (-72 to +18) that lacks TATA and CCAAT elements. The transcriptional start site was mapped to an initiator region by RNase protection of mRNA from human HepG2 cells, and by primer extension of in vitro-generated transcripts, to a sequence that is highly similar to the dihydrofolate reductase family of initiators. Deletion of this region (+1 to +18) severely impairs transcription initiation. Sp1 core elements centered at nucleotides -21 and -39 define the activation domain of the proximal promoter. Only the -39 element is protected from DNase I in the presence of crude nuclear extracts. However, transfection, gel-mobility-shift, supershift and in vitro-transcription experiments show that the -21 element binds Sp1 protein and contributes to transcription activation. No other functional oxidative-phosphorylation-specific response elements have been identified. These data implicate Sp1 as a single activating factor for an oxidative-phosphorylation gene. |
| Databáze: | OpenAIRE |
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