Send to

Choose Destination
See comment in PubMed Commons below
Cancer Res. 2003 Oct 15;63(20):6579-82.

p53-mediated repression of DNA methyltransferase 1 expression by specific DNA binding.

Author information

Departments of Biology and Microbiology & Immunology, Virginia Commonwealth University, Richmond, Virginia 23298, USA.


Cytosine methylation patterns in genomic DNA are significantly altered in cancer, and de novo CpG island methylation has been implicated in tumor suppressor gene silencing. Here we demonstrate a mechanistic link between the p53 tumor suppressor gene and control of epigenetic regulation by genomic methylation. Deletion of p53in HCT116 human colon carcinoma cells and primary mouse astrocytes resulted in a 6-fold increase of DNA cytosine methyltransferase 1 (Dnmt1) mRNA and protein, suggesting relief of p53-mediated Dnmt1repression. A p53 consensus binding site in exon 1 of the human Dnmt1gene bound recombinant p53 in vitro and endogenous p53 in vivo in the absence of stimuli that activate p53, implying that p53 controls Dnmt1transcription through direct DNA binding. Interestingly, ionizing radiation or etoposide, both of which stabilize and activate p53, diminished p53 binding in chromatin immunoprecipitation assays, concomitant with a 5-fold increase in Dnmt1 levels. Our findings suggest that activation of p53 reduces binding and relieves transcriptional repression of the Dnmt1gene, whereas loss of p53, a frequent, early event in tumorigenesis, may significantly contribute to aberrant genomic methylation.

[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Support Center