5-methylcytosine RNA methylation process (m5C RNA methylation)

Molecular Classification

Other (Epitranscriptomic modification), Enzyme (NSUN and DNMT2 are methyltransferases involved; TET and ALKBH1 are demethylases; "readers" such as ALYREF/YBX1 are RNA-binding proteins)

Other Names

RNA 5-methylcytosine modification, 5-methylcytosine methylation in RNA, RNA m5C modification, RNA cytosine-5 methylation

Disease Roles

Cancer (involvement in tumorigenesis, progression, and prognosis)Autoimmune diseaseAtherosclerosis

5-methylcytosine RNA methylation process Overview

The 5-methylcytosine (m5C) RNA methylation process refers to the enzymatic addition of a methyl group to the fifth carbon of cytosine in RNA molecules, a key epitranscriptomic mark that affects both coding (mRNA) and non-coding (tRNA, rRNA, miRNA) RNAs[1][3][5][7][9]. This reversible process is catalyzed by "writer" enzymes (NSUN family, DNMT2/TRDMT1), removed by "erasers" (TET family, ALKBH1), and interpreted by "reader" proteins (ALYREF, YBX1, etc.)[1][3][7][9]. m5C RNA methylation participates in regulating RNA structure, stability, export, translation, and cellular stress responses. Dysregulation of m5C methylation or its effectors is implicated in cancer, autoimmune disease, cardiovascular disease, and neurological disorders[1][3][5][7][9]. m5C methylation is an active area of research in epitranscriptomics but is not itself considered a direct therapeutic target; rather, the individual proteins mediating the addition, removal, or recognition of m5C are the true molecular drug targets. Note: This entry describes a process, not a targetable molecule, so most structured target fields such as "mechanism of action", "interacting drugs", etc., are not directly applicable except when considering specific proteins (e.g., NSUN2 methyltransferase) rather than the process as a whole.

Mechanism of Action

At the process level, not applicable—individual enzymes (writers/erasers) could be inhibited or activated to alter m5C levels, but the process itself is not a drug target

Biological Functions

Regulation of RNA stability

RNA splicing

Regulation of translation efficiency

RNA transport (nucleocytoplasmic export)

Regulation of RNA degradation

Influence on cell metabolism, proliferation, differentiation, migration, apoptosis

Stress response and development

Disease Associations

Cancer (involvement in tumorigenesis, progression, and prognosis)

Autoimmune disease

Atherosclerosis

Neurological disorders

Other (altered m5C or its regulators implicated in various pathologies)

Safety Considerations

None at the process level. Therapeutic modulation of RNA methylation could, in principle, impact broad cellular functions, affecting cell viability, proliferation, and differentiation, and may lead to unintended consequences such as oncogenic transformation or impaired development if not targeted precisely

Associated Biomarkers

Biomarker
Aberrant expression or mutation of RNA m5C writers (e.g., NSUN2, NSUN5, DNMT2) in tumors or diseased tissues may serve as biomarkers for cancer diagnosis, prognosis, or patient stratification
m5C methylation levels in specific RNAs, measured by sequencing or mass spectrometry