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Homocysteine Induces DNA Methyltransferase 1 Transcription Through the cAMP Response Element in the DNMT1 Promoter
Author(s) -
ALENAD Amal
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.880.3
Subject(s) - dnmt1 , dna methyltransferase , dna methylation , methyltransferase , promoter , methylation , microbiology and biotechnology , chemistry , response element , cpg site , binding site , dna , gene expression , biology , biochemistry , gene
DNA methyltransferase 1 (DNMT1) is essential for the maintenance of DNA methylation patterns. One‐carbon metabolism supplies methyl groups for DNA methylation and is dependent upon nutrients that act as methyl group donors like folate and methyl group acceptors like homocysteine (Hcy) to methylate CpG dinucleotides in gene promoters.To investigate the effect of Hcy on the expression of the DNMT1, the rat liver cell line CC1 was treated with increasing concentrations of Hcy for 24 and 72hrs. Given that the physiological plasma level of Hcy range between 5 – 15μM, CC1 cells were treated with Hcy at 0.1, 1, 5, 10 and 50μM and the expression of the DNMT1were measured using RT‐PCR and have shown that Hcy can alter the expression of DNMT1. There was a significant increase in the expression of DNMT1 at 1μM (6 folds) and at 5μM (8 folds) in CC1 cells. To learn more about the mechanism of Hcy induction of DNMT1, the promoter region of DNMT1 (‐3000bp to +15bp) was cloned into the reporter vector pGl3basic. Where the cAMP response element binding protein (CREB) binding site was predicted in the promoter of DNMT1 but located at ‐2633bp. This construct did respond to Hcy and mutation of the predicted CREB binding site to an EcoR1 site abolished the induction of DNMT1 promoter activity by Hcy, suggesting that Hcy induction of DNMT1 may be mediated through theCREB binding site in the promoter region of DNMT1.