Distinct mA methylome profiles in poly(A) RNA from Xenopus laevis testis and that treated with atrazine.

Recent discovery of reversible N-methyladenosine (mA) methylation on messenger RNA (mRNA) and mapping of mA methylomes in mammals, plant and yeast revealed potential regulatory functions of this RNA modification. However, the role of the mA methylomes in amphibious is still poorly understood. Here, we examined the mA transcriptome-wide profile in testis tissues of Xenopus laevis (X. laevis) with and without treatment with 100 μg/L atrazine (AZ) through mA sequencing analysis using the latest Illumina HiSeq sequencer. The results revealed that mA is a highly conserved modification of mRNA in X. laevis. Distinct from that in mammals, mA in X. laevisis enriched around the stop codon and start codon, as is reported in plant. We then investigated the differential expression mA in testes of AZ-exposed X. laevis and compared that with the X. laevis in the control group by mA sequencing. The results indicated that AZ leads to altered expression profile in 1380 mA 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 mA modification and mRNA abundance, suggesting a regulatory role of mA in amphibious gene expression. Our first report of mA transcriptome-wide map of an amphibian species X. laevis presented here provides a starting roadmap for uncovering mA functions that may affect/control amphibian testis development.