Translational adaptation to heat stress is mediated by RNA 5-methylcytosine in Caenorhabditis elegans.

Abstract

ABSTRACT Methylation of carbon-5 of cytosines (m 5 C) is a post-transcriptional nucleotide modification of RNA found in all kingdoms of life. While individual m 5 C-methyltransferases have been studied, the impact of the global cytosine-5 methylome on development, homeostasis and stress remains unknown. Here, using Caenorhabditis elegans , we generated the first organism devoid of m 5 C in RNA, demonstrating that this modification is non-essential. We determined the localisation and enzymatic specificity of m 5 C sites in RNA in vivo and showed that animals devoid of m 5 C are sensitive to temperature stress. At the molecular level, we showed that loss of m 5 C specifically impacts decoding of leucine and proline thus reducing the translation efficiency of transcripts enriched in these amino acids. Finally, we found translation of leucine UUG codons to be the most strongly affected upon heat shock, suggesting a role of m 5 C tRNA wobble methylation in the adaptation to heat stress.