Transcriptome-wide mapping of internal mRNA N7-methylguanosine in sporulated and unsporulated oocysts of Eimeria tenella reveals stage-specific signatures

Abstract

BackgroundGrowing evidence indicates that N7-methylguanosine (m7G) modification plays critical roles in epigenetic regulation. However, no data regarding m7G modification are currently available in Eimeria tenella, a highly virulent species causing coccidiosis in chickens.MethodsIn the present study, we explore the distribution of internal messenger RNA (mRNA) m7G modification in sporulated and unsporulated oocysts of E. tenella as well as its potential biological functions during oocyst development using methylated RNA immunoprecipitation sequencing (MeRIP-seq) and mRNA sequencing (mRNA-seq), and the mRNA-seq and MeRIP-seq data were verified by the quantitative reverse transcription polymerase chain reaction (RT–qPCR) and MeRIP–qPCR, respectively.ResultsOur data showed that m7G peaks were detected throughout the whole mRNA body, and the coding DNA sequence (CDS) region displayed the most methylation modification. Compared with unsporulated oocysts, 7799 hypermethylated peaks and 1945 hypomethylated peaks were identified in sporulated oocysts. Further combined analysis of differentially methylated genes (DMGs) and differentially expressed genes (DEGs) showed that there was a generally positive correlation between m7G modification levels and gene transcript abundance. Unsurprisingly, the mRNA-seq and MeRIP-seq data showed good consistency with the results of the RT–qPCR and MeRIP–qPCR, respectively. Gene Ontology (GO) and pathway enrichment analysis of DEGs with altered m7G-methylated peaks were involved in diverse biological functions and pathways, including DNA replication, RNA transport, spliceosome, autophagy-yeast, and cAMP signaling pathway.ConclusionsAltogether, our findings revealed the potential significance of internal m7G modification in E. tenella oocysts, providing some directions and clues for later in-depth research.Graphical abstract