Abstract
5-methylcytosine (m5C) is a well-characterized DNA modification, and is also predominantly reported in abundant noncoding RNAs in both prokaryotes and eukaryotes. However, the distribution and biological functions of m5C in plant mRNAs remain largely unknown. Here we report transcriptome-wide profiling of RNA m5C in Arabidopsis thaliana through applying m5C RNA immunoprecipitation followed by deep sequencing approach (m5C-RIP-seq). LC-MS/MS and dot blot analyses reveal a dynamic pattern of m5C mRNA modification in various tissues and at different developmental stages. m5C-RIP-seq analysis identifies 6,045 m5C peaks in 4,465 expressed genes in young seedlings. m5C is enriched in coding sequences with two peaks located immediately after start codons and before stop codons, and is associated with mRNAs with low translation activity. We show that a RNA (cytosine-5)-methyltransferase, tRNA specific methyltransferase 4B (TRM4B), exhibits the m5C RNA methyltransferase activity. Mutations in TRM4B display defects in root development and decreased m5C peaks. TRM4B affects transcript levels of the genes involved in root development, which is positively correlated with their mRNA stability and m5C levels. Our results suggest that m5C in mRNA is a new epitranscriptome marker in Arabidopsis, and that regulation of this modification is an integral part of gene regulatory networks underlying plant development.
Key words
5-methylcytosine (m5C); Arabidopsis; RNA methylation; TRM4B; root development
|