Target type: molecularfunction
Catalysis of the reaction: S-adenosyl-L-methionine + DNA containing CpN = S-adenosyl-L-homocysteine + DNA containing 5-MeCpN. [EC:2.1.1.37, PMID:15689527]
DNA (cytosine-5-)-methyltransferase activity, acting on CpN substrates, refers to the enzymatic process by which a methyl group (CH3) is added to the 5' position of cytosine bases within DNA. This specific activity is characterized by its preference for CpN dinucleotides, where 'C' represents cytosine and 'N' represents any nucleotide. The methylation reaction is catalyzed by DNA methyltransferases (DNMTs), a family of enzymes that play crucial roles in various cellular processes, including gene regulation, genomic imprinting, and DNA repair.
The process begins with the DNMT recognizing and binding to the CpN site within the DNA sequence. The enzyme then utilizes S-adenosyl methionine (SAM) as a methyl donor, transferring the methyl group to the 5' position of cytosine. The reaction results in the formation of 5-methylcytosine (5mC), a modified base that can alter DNA structure and influence the binding of proteins to specific DNA regions.
The molecular function of this activity is intimately linked to gene regulation. Methylation patterns within CpN-rich regions, known as CpG islands, are often associated with transcriptional silencing. When CpG islands are heavily methylated, they tend to repress gene expression by inhibiting the binding of transcription factors and promoting the recruitment of repressor proteins. Conversely, demethylation of CpG islands is often linked to gene activation.
Furthermore, DNA (cytosine-5-)-methyltransferase activity plays a critical role in genomic imprinting, a phenomenon where parental origin influences gene expression. Differential methylation patterns are established during gametogenesis and maintained throughout development, ensuring proper expression of imprinted genes.
In summary, DNA (cytosine-5-)-methyltransferase activity, acting on CpN substrates, is a fundamental enzymatic process that adds a methyl group to cytosine bases within DNA. This activity significantly influences gene expression, genomic imprinting, and other essential cellular processes by modifying DNA structure and influencing protein binding.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| DNA (cytosine-5)-methyltransferase 3B | A DNA (cytosine-5)-methyltransferase 3B that is encoded in the genome of mouse. [OMA:O88509, PRO:DNx] | Mus musculus (house mouse) |
| DNA (cytosine-5)-methyltransferase 3A | A DNA (cytosine-5)-methyltransferase 3A that is encoded in the genome of mouse. [OMA:O88508, PRO:DNx] | Mus musculus (house mouse) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| cblc137 | CBL0137 : A member of the class of carbazoles that is 9H-carbazole which is substituted by acetyl groups at positions 3 and 6, and by a 2-isopropylethyl group on the nitrogen atom (position 9). It is a modulator of histone chaperone FACT (FAcilitates Chromatin Transcription) - interaction of CBL0137 with the FACT complex results in simultaneous NF-kappa beta suppression, Heat Shock Transcription Factor 1 (HSF1) suppression and p53 activation - and shows antitumour effects in animal models of various cancers. CBLC137: a FACT histone chaperone inhibitor with antineoplastic activity; structure in first source | aromatic ketone; carbazoles; methyl ketone; secondary amino compound; tertiary amino compound | antineoplastic agent; apoptosis inducer; NF-kappaB inhibitor; p53 activator |
| gsk343 | GSK343 : A member of the class of indazoles that is 1-isopropyl-1H-indazole-4-carboxamide in which the nitrogen of the carboxamide group is substituted by a (6-methyl-2-oxo-4-propyl-1,2-dihydropyridin-3-yl)methyl group and in which the indazole ring is substituted at position 6 by a 2-(4-methylpiperazin-1-yl)pyridin-4-yl group. A highly potent and selective EZH2 inhibitor (IC50 = 4 nM). GSK343: an EZH2 methyltransferase inhibitor | aminopyridine; indazoles; N-alkylpiperazine; N-arylpiperazine; pyridone; secondary carboxamide | antineoplastic agent; apoptosis inducer; EC 2.1.1.43 (enhancer of zeste homolog 2) inhibitor |