Cross-species comparative transcriptomic analysis of spermatozoa reveals species-specific regulatory networks linked to fertilization-associated genes in cattle, sheep and goats
摘要
Mammalian sperm RNAs, encompassing coding and non-coding sequences, have historically been considered residual by-products of spermatogenesis. However, accumulating evidence has revealed that mature sperm-derived RNAs not only participate in zygote formation and embryonic cleavage but also exhibit multifaceted biological functions. Notably, interspecies variations in sperm transcriptomic profiles among cattle, sheep, and goats, particularly those linked to species-specific regulatory networks with fertilization-associated genes, remain underexplored. This study systematically characterized mRNAs, miRNAs, and circRNAs components within sperm transcriptomes across these three ruminant species, with comparative analysis of interspecies divergence. High-throughput sequencing identified distinct RNA repertoires: cattle sperm contained 15,661 mRNAs, 442 miRNAs, and 3,358 circRNAs; sheep sperm comprised 13,883 mRNAs, 474 miRNAs, and 3,449 circRNAs; goat sperm exhibited 15,725 mRNAs, 588 miRNAs, and 5,081 circRNAs. Cross-species comparisons revealed that 5,782 differentially expressed mRNAs, 11 differentially expressed miRNAs, and 60 differentially expressed circRNAs were shared by the three species, alongside species-unique gene clusters. A competitive endogenous RNAs (ceRNA) network integrating mRNAs, miRNAs, and circRNAs was constructed, and species-specific regulatory networks associated with fertilization were identified, including circMEMOl-bta-miR-497-IZUMO4, circAKT2-novel-bta-miR433-3p-CATSPERD, circFBXW7-novel-bta-miR382-3p-CATSPER2, circSTAU1-novel-oar-miR1301-5p-PRM3, and circJMJD1C-novel-chi-miR2159-3p-IZUMO2. This study demonstrates the interspecies divergences in sperm transcriptomic profiles and regulatory networks among cattle, sheep, and goats, establishing a novel research paradigm centered on ‘coding & non-coding RNAs interplay’ in mammalian sperm transcriptomic regulation, and thereby providing a generalizable systematic analytical tool for deciphering complex reproductive biological processes.