Mouse Anti Human Methyl CpG Binding Protein 1 Hybridoma [DQUD-NCE2-3]

DNA methylation is an epigenetic modification that is implicated in transcriptional silencing. Recently, it has become increasingly clear that both correct levels and proper interpretation of methylation are important factors for normal development and function of the human organism. One example is the neurological disorder Rett syndrome (RTT), which affects approximately one in 10,000 girls. RTT is caused by mutations in MeCP2, a protein that was identified by its ability to bind specifically to CpG-methylated DNA. Furthermore, MeCP2 represses transcription in a methylation-dependent manner, and it is the founding member of the family of methyl-CpG binding domain (MBD) proteins. (C) 2002 Wiley-Liss, Inc.

Aberrations in methylation profile of the genome occur in human cancers induced by folate deficiency. To elucidate the underlying mechanism, male F344 rats were fed a diet deficient in L-methionine and devoid of folic acid and choline (FMD diet), which is known to induce hepatocellular carcinomas. We investigated changes in the DNA methylation machinery, namely, de novo DNA methyltransferases (Dnmt3a and 3b), maintenance DNA methyltransferase (Dnmt1), and methyl CpG binding proteins (MBDs), in rat livers during early stages of tumorigenesis. RTPCR and Western blot analyses revealed differential expression of these proteins in the livers of rats fed the FMD diet. Although the hepatic Dnmt1 mRNA level declined with age (P < 0.001), it was elevated (P < 0.001) in deficient rats compared with controls. The changes in hepatic Dnmt1 protein level with the diet correlated with its mRNA levels (r=0.60, P=0.002). Similarly, the Dnmt3a mRNA level was elevated in rats fed the FMD diet (P < 0.001), whereas the Dnmt3b level (mRNA and protein) was not affected by diet or age. Compared with controls, hepatic MBD1-3 RNA levels increased (P < 0.001) and the protein levels of MBD1, 2, and 4 were elevated (P < 0.001) in the deficient rats. In both diet groups, hepatic MBD2 protein decreased (P < 0.001), whereas MeCP2 protein increased (P < 0.001) with age. These results demonstrate that a combined folate and methyl deficiency alters components of the DNA methylation machinery by both transcriptional and posttranscriptional mechanisms during early stages of hepatocarcinogenesis.