Posttranscriptional methylation of transfer and ribosomal RNA in stress response pathways, cell differentiation, and cancer.

PURPOSE OF REVIEW: Significant advances have been made in understanding the functional roles of evolutionarily conserved chemical modifications in RNA. By focusing on cytosine-5 methylation, we will highlight the latest insight into the mechanisms how posttranscriptional methylation contributes to cell fate decisions, with implications for cancer development. RECENT FINDINGS: Several mutations in RNA-modifying enzymes have been identified to cause complex human diseases, and linked posttranscriptional modifications to fundamental cellular processes. Distinct posttranscriptional modifications are implicated in the regulation of stem cell maintenance and cellular differentiation. The dynamic deposition of a methyl mark into noncoding RNAs modulates the adaptive cellular responses to stress and alterations of methylation levels may lead to cancer. SUMMARY: Posttranscriptional modifications such as cytosine-5 methylation are dynamically regulated and may influence tumour development, maintenance, and progression.