MGMT DNA repair gene promoter/enhancer haplotypes alter transcription factor binding and gene expression

Meixiang Xu, Courtney E. Cross, Jordan T. Speidel, Sherif Abdel-Rahman

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Background: The O6-methylguanine-DNA methyltransferase (MGMT) protein removes O6-alkyl-guanine adducts from DNA. MGMT expression can thus alter the sensitivity of cells and tissues to environmental and chemotherapeutic alkylating agents. Previously, we defined the haplotype structure encompassing single nucleotide polymorphisms (SNPs) in the MGMT promoter/enhancer (P/E) region and found that haplotypes, rather than individual SNPs, alter MGMT promoter activity. The exact mechanism(s) by which these haplotypes exert their effect on MGMT promoter activity is currently unknown, but we noted that many of the SNPs comprising the MGMT P/E haplotypes are located within or in close proximity to putative transcription factor binding sites. Thus, these haplotypes could potentially affect transcription factor binding and, subsequently, alter MGMT promoter activity. Methods: In this study, we test the hypothesis that MGMT P/E haplotypes affect MGMT promoter activity by altering transcription factor (TF) binding to the P/E region. We used a promoter binding TF profiling array and a reporter assay to evaluate the effect of different P/E haplotypes on TF binding and MGMT expression, respectively. Results: Our data revealed a significant difference in TF binding profiles between the different haplotypes evaluated. We identified TFs that consistently showed significant haplotype-dependent binding alterations (p ≤ 0.01) and revealed their role in regulating MGMT expression using siRNAs and a dual-luciferase reporter assay system. Conclusions: The data generated support our hypothesis that promoter haplotypes alter the binding of TFs to the MGMT P/E and, subsequently, affect their regulatory function on MGMT promoter activity and expression level.

Original languageEnglish (US)
Pages (from-to)1-13
Number of pages13
JournalCellular oncology (Dordrecht)
DOIs
StateAccepted/In press - Jun 15 2016

Fingerprint

Methyltransferases
DNA Repair
Haplotypes
Transcription Factors
Gene Expression
DNA
Genes
Single Nucleotide Polymorphism
Genetic Promoter Regions
Protein Methyltransferases
DNA Adducts
Alkylating Agents
Guanine
Luciferases
Binding Sites

Keywords

  • MGMT P/E haplotypes
  • Promoter activity
  • siRNA regulation
  • Transcription factor binding

ASJC Scopus subject areas

  • Cancer Research
  • Molecular Medicine
  • Oncology

Cite this

MGMT DNA repair gene promoter/enhancer haplotypes alter transcription factor binding and gene expression. / Xu, Meixiang; Cross, Courtney E.; Speidel, Jordan T.; Abdel-Rahman, Sherif.

In: Cellular oncology (Dordrecht), 15.06.2016, p. 1-13.

Research output: Contribution to journalArticle

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