metylaation

Metylaation is a term that appears to be a misspelling or variant of methylation. In standard scientific usage, the recognized process is methylation, the biochemical transfer of a methyl group (CH3) to substrates such as DNA, RNA, or proteins.

DNA methylation involves adding a methyl group to cytosine residues, mainly at CpG dinucleotides, by DNA methyltransferases (DNMT1, DNMT3A, DNMT3B). It plays a key role in regulating gene expression, in genomic imprinting, and in X-chromosome inactivation, while helping silence transposable elements. Reversible demethylation can occur through passive loss during replication or via TET enzymes and base excision repair pathways.

RNA methylation encompasses several modified nucleotides, including N6-methyladenosine (m6A) and 5-methylcytosine (m5C). Writers such as the METTL3–METTL14 complex install m6A, readers interpret the modification through YTH domain proteins, and erasers like FTO and ALKBH5 can remove it. RNA methylation influences mRNA stability, splicing, localization, and translation, contributing to post-transcriptional regulation.

Protein methylation refers to the addition of methyl groups to amino acid residues, most notably lysine and arginine. Protein methyltransferases (including histone methyltransferases) modify chromatin structure and regulate protein interactions, activity, and localization, with broad implications for signaling and transcriptional control.

Biological and medical relevance is extensive, including development, aging, and diseases such as cancer and neurological disorders. Methods to study methylation include bisulfite sequencing for DNA, MeRIP-seq for RNA, and targeted proteomics for protein methylation. See also methylation and epigenetics.