DNA polymerase beta gene expression: the promoter activator CREB-1 is upregulated in Chinese hamster ovary cells by DNA alkylating agent-induced stress.
The DNA alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) upregulates the level of the base excision DNA repair enzyme DNA polymerase beta (beta-pol) in several mammalian cell types. Previous studies suggested that beta-pol expression is upregulated via a transcriptional mechanism that requires: the specific cAMP response element (CRE) in the beta-pol core promoter; a phosphorylated form of CRE-binding protein-1 (CREB-1); and cellular protein kinase A activity. A large family of CRE-binding proteins, ie., the ATF/CREB factors, has been identified in various cell types. This study further examines the role of CRE-binding proteins in regulating beta-pol expression through study of Chinese hamster ovary (CHO) cells. In CHO cell nuclear extract, CREB-1 and ATF-1 are the predominant CRE-binding protein family members recognizing the CRE in the beta-pol core promoter. The concentration of CREB-1 increases strongly in CHO cells after exposure to MNNG. In contrast, the level of ATF-1 does not change after MNNG treatment. Recombinant expression of CREB-1 in CHO cells is sufficient to increase expression of the endogenous beta-pol gene, even in the absence of MNNG exposure. These results indicate that beta-pol gene expression in CHO cells can be upregulated by CREB-1 and that the activation of beta-pol gene expression in response to DNA alkylating agent exposure involves a strong increase in the level of CREB-1.
He
Feng
F
Sealy Center for Molecular Science, University of Texas Medical Branch, Galveston, TX 77555-1068, USA.
Yang
Xiao-Ping
XP
Srivastava
Deepak K
DK
Wilson
Samuel H
SH
D051697:Activating Transcription Factor 1; D000477:Alkylating Agents / Q000494:pharmacology*; D000818:Animals; D016466:CHO Cells; D002467:Cell Nucleus; D006224:Cricetinae; D017362:Cyclic AMP Response Element-Binding Protein; D017868:Cyclic AMP-Dependent Protein Kinases / Q000096:biosynthesis / Q000235:genetics; D004247:DNA / Q000187:drug effects*; D019951:DNA Polymerase beta / Q000235:genetics*; D004268:DNA-Binding Proteins; D024202:Electrophoretic Mobility Shift Assay; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis* / Q000378:metabolism; D014162:Transfection; D015854:Up-Regulation / Q000235:genetics*
D051697:Activating Transcription Factor 1; D000477:Alkylating Agents; C115163:CREB1 protein, human; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D008769:Methylnitronitrosoguanidine; D004247:DNA; D017868:Cyclic AMP-Dependent Protein Kinases; D019951:DNA Polymerase beta