The Caulobacter crescentus DNA methyltransferase CcrM (M.CcrMI) methylates the adenine residue in the sequence GANTC. The CcrM DNA methyltransferase is essential for viability, but it does not appear to be part of a DNA restriction-modification system. CcrM homologs are widespread in the alpha subdivision of gram-negative bacteria. We have amplified and sequenced a 258-bp region of the cerM gen...

In cobaiamin deficiency, inadequate DNA-thymine synthesis appears to resuit from decreased conversion of N5methyltetrahydrofolic acid to tetrahydrofo ic acid (THE). The N5-methyl THE conversion catalyzed by N5methyl THF-homocysteine methyltransferase requires a cobalamin coenzyme, presumed to be methylcobalamin (methyl-B12). In support of the above, in B12-deficient marrow cultures, methyl-B12 ...

Escherichia coli Dam DNA methyltransferase can methylate genomic GATC sites when expressed in Saccharomyces cerevisiae. Others have observed changes in the level of methylation at specific sites and suggested that these changes are related to transcriptional state or chromosomal context. To test directly the influence of nucleosome location on the ability of Dam methyltransferase to modify GATC...

Development of methods that will allow exogenous imposition of inheritable gene-specific methylation patterns has potential application in both therapeutics and in basic research. An ongoing approach is the use of targeted DNA methyltransferases, which consist of a fusion between gene-targeted zinc-finger proteins and prokaryotic DNA cytosine methyltransferases. These enzymes however have so fa...

A novel gene encoding a cytosine-5-DNA methyltransferase recognizing the dinucleotide GpC was cloned from Chlorella virus NYs-1 and expressed in both Escherichia coli and Saccharomyces cerevisiae . The gene was sequenced and a predicted polypeptide of 362 amino acids with a molecular weight of 41.903 kDa was identified. The protein contains several amino acid motifs with high similarity to thos...

We have partially purified a DNA methyltransferase from human placenta using a novel substrate for a highly sensitive assay of methylation of hemimethylated DNA. This substrate was prepared by extensive nick translation of bacteriophage XP12 DNA, which normally has virtually all of its cytosine residues replaced by 5-methylcytosine (m5C). Micrococcus luteus DNA was just as good a substrate if i...

DNA methylation is a central epigenetic modification in mammals, with essential roles in development and disease. De novo DNA methyltransferases establish DNA methylation patterns in specific regions within the genome by mechanisms that remain poorly understood. Here we show that protein citrullination by peptidylarginine deiminase 4 (PADI4) affects the function of the DNA methyltransferase DNM...

In cobaiamin deficiency, inadequate DNA-thymine synthesis appears to resuit from decreased conversion of N5methyltetrahydrofolic acid to tetrahydrofo ic acid (THE). The N5-methyl THE conversion catalyzed by N5methyl THF-homocysteine methyltransferase requires a cobalamin coenzyme, presumed to be methylcobalamin (methyl-B12). In support of the above, in B12-deficient marrow cultures, methyl-B12 ...