Multiple Isoforms of DNA Methyltransferase Are Encoded by the Vertebrate Cytosine DNA Methyltransferase Gene

DNMT 1 ( DNA ( cytosine - 5 - ) - methyltransferase 1 ) )

DNA ( cytosine - 5 ) - methyltransferase 1 - [ Isoform 1 ]

The murine equivalent of the human DNMT1 (DNA [cytosine-5]-methyltransferase 1; Swiss-Prot accession number: P26358) gene was deleted in ES cells via gene targeting [1]. Dnmt1-/cells possessed dramatically decreased genomic methylation and were viable; however, the mutation caused a homozygous lethal phenotype when introduced into the germline (see Table of experimental models for DNMT1) [1]. C...

Protein-facilitated base flipping in DNA by cytosine-5-methyltransferase.

DNA methylation, various DNA repair mechanisms, and possibly early events in the opening of DNA as required for transcription and replication are initiated by flipping of a DNA base out of the DNA double helix. The energetics and structural mechanism of base flipping in the presence of the DNA-processing enzyme, cytosine 5-methyltransferase from HhaI (M.HhaI), were obtained through molecular dy...

Cytosine-to-Uracil Deamination by SssI DNA Methyltransferase

The prokaryotic DNA(cytosine-5)methyltransferase M.SssI shares the specificity of eukaryotic DNA methyltransferases (CG) and is an important model and experimental tool in the study of eukaryotic DNA methylation. Previously, M.SssI was shown to be able to catalyze deamination of the target cytosine to uracil if the methyl donor S-adenosyl-methionine (SAM) was missing from the reaction. To test ...

Methylation inhibitors can increase the rate of cytosine deamination by (cytosine-5)-DNA methyltransferase.

The target cytosines of (cytosine-5)-DNA methyltransferases in prokaryotic and eukaryotic DNA show increased rates of C-->T transition mutations compared to non-target cytosines. These mutations are induced either by the spontaneous deamination of 5-mC-->T generating inefficiently repaired G:T rather than G:U mismatches, or by the enzyme-induced C-->U deamination which occurs under conditions o...