Role of DNA methyltransferases in regulation of human ribosomal RNA gene transcription.

ABSTRACT: We have previously demonstrated that the expression of human ribosomal RNA genes (rDNA) in normal and cancer cells is differentially regulated by methylation of the promoter CpG islands. Furthermore, we showed that the methyl CpG-binding protein MBD2 plays a selective role in the methylation-mediated block in rDNA expression. Here, we analyzed the role of three functional mammalian DNA methyltransferases (DNMTs) in regulating the rDNA promoters activity. Immunofluorescence analysis and biochemical fractionation showed that all three DNMTs (DNMT1, DNMT3A, and DNMT3B) are associated with the inactive rDNA in the nucleolus. Although DNMTs associate with both methylated and unmethylated rDNA promoters, DNMT1 preferentially associates with the methylated genes. The rDNA primary transcript level

SUBMITTER: Majumder S 

PROVIDER: S-EPMC2243234 | biostudies-literature | 2006 Aug

REPOSITORIES: biostudies-literature