M6A transcriptome-wide map of circRNAs identified in the testis of normal and AZ-treated Xenopus laevis

Abstract

Abstract Background Evidence showed that N6-methyladenosine (m6A) is strongly associated with male germline development. However, the role of m6A methylation on circRNAs in amphibians remains unknown. In this study, we conducted m6A sequencing analysis to explore the m6A transcriptome-wide profile of circRNAs in testis tissues of Xenopus laevis (X. laevis) with and without treatment with 100 µg/L atrazine (AZ). Results The analysis showed that m6A modification of circRNAs enriched in sense overlapping in testes of X. laevis. We identified the differential m6A modification sites within circRNAs in testes of AZ-exposed X. laevis and compared that with animals from control group. The results showed that a total of 1507 methylated m6A sites was induced by AZ (760 up-methylated and 747 down-methylated). The cross-analysis exhibited a negative correlation of differentially methylated m6A peaks and circRNAs expression level. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that 20 key pathways may be involved in the mechanism of testis damage of AZ-exposed X. laevis. Conclusions These findings indicated that differentially m6A-methylated circRNAs may play important roles in abnormal testis development of AZ-exposed X. laevis. This study is the first report about a map of m6A modification of circRNAs in male X. laevis and provides a basis for further studying on the function and mechanism of m6A methylation of circRNAs in the testis development of amphibian.