High-throughput Sequencing Reveals Differential Expression Of Mi Rnas In Yak And Cattleyak Epididymis

The yak(Bos grunniens)is a herd of animals that live at high altitude on the Qinghai–Tibetan Plateau.Cattleyak hybrid is derived from a cross between cattle(Bos taurus)and yak(Bos grunniens),which shows obvious heterosis including fast growth,early maturity and high milk production compared with cattle and yak.However,male infertility of CY has greatly restricted their effective utilization to improve the yak breeding.So far,much work have been conducted to uncover the mechanism of male infertility in CY,however,no study yet been conducted on the role of mi RNAs in regulation of candidate gene expression,especially between CY and YK epididymis.Micro RNAs are small noncoding RNAs that play important roles in posttranscriptional gene regulation,generally by binding to specific motifs in the 3’?untranslated regions(3’UTRs)of target genes.In present study,High-throughput sequencing analysis showed that 55 DE mi RNAs were identified in the epididymis of YK and CY.From these,43 DE mi RNAs were up-regulated while the remaining 12 DE mi RNAs were down-regulated between epididymis of YK and CY.Our result showed that the top most important DE mi RNAs,bta-mi R-449 c,btami R-539,bta-mi R-136,bta-mi R-504,bta-mi R‐31 and bta-mi R-222 were found to be involved in the reproductive system of CY.In addition,some targeted genes,Clusterins(CLU),Retinoic Acid Receptor a(RARa),and Hydroxy acyl glutathione Hydrolase(HAGH)and HSPH1 targeted by bta-mi R-2411-3p and bta-mi R-1298 were involved in the sperm motility,sperm morphology,and post-testicular sperm maturation.Furthermore,GO and KEGG analyses were performed to classify the functions of target genes for DE mi RNAs.In addition,RT-q PCR validation of the DE mi RNAs and its targeted genes revealed that putative mi RNAs are involved in the male CY infertility by altering the gene expression.Present findings may not only increase our understanding of the molecular mechanisms regulated by the mi RNAs in epididymis,but rather,it could provide a valuable information to understand the male infertility mechanism of CY.