Abstract
Recent discovery of reversible N6-methyladenosine (m6A) methylation on messenger RNA (mRNA) and mapping of m6A methylomes in mammals, plant and yeast revealed potential regulatory functions of this RNA modification. However, the role of the m6A methylomes in amphibious is still poorly understood. Here, we examined the m6A transcriptome-wide profile in testis tissues of Xenopus laevis (X. laevis) with and without treatment with 100 μg/L atrazine (AZ) through m6A sequencing analysis using the latest Illumina HiSeq sequencer. The results revealed that m6A is a highly conserved modification of mRNA in X. laevis. Distinct from that in mammals, m6A in X. laevisis enriched around the stop codon and start codon, as is reported in plant. We then investigated the differential expression m6A in testes of AZ-exposed X. laevis and compared that with the X. laevis in the control group by m6A sequencing. The results indicated that AZ leads to altered expression profile in 1380 m6A modification sites (696 upregulated and 684 downregulated). KEGG pathway analysis indicates that the "NOD-like receptors", "tight junction", "Peroxisome proliferator-activated receptors", "adherens junctions", "Glycerophospholipid metabolism" and "Fatty acid biosynthesis" signaling pathways may be associated with abnormal testis development of X. laevis due to exposure to AZ. Analysis results showed a positive correlation between m6A modification and mRNA abundance, suggesting a regulatory role of m6A in amphibious gene expression. Our first report of m6A transcriptome-wide map of an amphibian species X. laevis presented here provides a starting roadmap for uncovering m6A functions that may affect/control amphibian testis development.