Accessory elements, flanking DNA sequence, and promoter context play key roles in determining the efficacy of insulin and phorbol ester signaling through the malic enzyme and collagenase-1 AP-1 motifs
| Autor: | Christina A. Svitek, Julio E. Ayala, Ryan S. Streeper, Joshua K. Goldman, Richard M. O'Brien, James K. Oeser |
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| Rok vydání: | 2002 |
| Předmět: |
Chloramphenicol O-Acetyltransferase
medicine.medical_treatment Malic enzyme Biology Transfection Biochemistry Polymerase Chain Reaction Gene Expression Regulation Enzymologic Cell Line Fusion gene Malate Dehydrogenase Phorbol Esters medicine Humans Insulin Collagenases Promoter Regions Genetic Molecular Biology Transcription factor DNA Primers Base Sequence Activator (genetics) Cell Biology beta-Galactosidase Recombinant Proteins Transcription Factor AP-1 Oligodeoxyribonucleotides Cell culture Mutagenesis Acetyltransferase HeLa Cells Transcription Factors |
| Zdroj: | The Journal of biological chemistry. 277(31) |
| ISSN: | 0021-9258 |
| Popis: | Insulin stimulates malic enzyme (ME)-chloramphenicol acetyltransferase (CAT) and collagenase-1-CAT fusion gene expression in H4IIE cells through identical activator protein-1 (AP-1) motifs. In contrast, insulin and phorbol esters only stimulate collagenase-1-CAT and not ME-CAT fusion gene expression in HeLa cells. The experiments in this article were designed to explore the molecular basis for this differential cell type- and gene-specific regulation. The results highlight the influence of three variables, namely promoter context, AP-1 flanking sequence, and accessory elements that modulate insulin and phorbol ester signaling through the AP-1 motif. Thus, fusion gene transfection and proteolytic clipping gel retardation assays suggest that the AP-1 flanking sequence affects the conformation of AP-1 binding to the collagenase-1 and ME AP-1 motifs such that it selectively binds the latter in a fully activated state. However, this influence of ME AP-1 flanking sequence is dependent on promoter context. Thus, the ME AP-1 motif will mediate both an insulin and phorbol ester response in HeLa cells when introduced into either the collagenase-1 promoter or a specific heterologous promoter. But even in the context of the collagenase-1 promoter, the effects of both insulin and phorbol esters, mediated through the ME AP-1 motif are dependent on accessory factors. |
| Databáze: | OpenAIRE |
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