Screening And Identification Of Ovarian MiRNA Invorlved In Puberty Initiation In Goat

Puberty is the period that female mammalians enter estrus and ovulate for the first time,and it marks that mammalians are capable of reprodution.To clarify the mechanism of puberty initiation has great influence on animal science and medicine.Micro RNAs?mi RNA?is a kind of non-coding small RNA which can bind to the target m RNA based on the principle of complementary base pairing,lead to endonucleolytic cleavage or interfere with the translation of target m RNA.It was reported that mi RNA was involved in the regulation of puberty initiation.To investigate the role of mi RNAs in puberty intiation in female goat,2 pooled samples of ovarian mi RNAs respectively from 3 puberal goats and 3prepuberty goats were sequenced and compared with each other.All mi RNAs that may potentially involved in the puberty initiation in goats were screened,and the target genes were subjected to GO enrichment and KEGG pathway analysis.The main results are as follows:?1?Follicles at all stages were found in both prepuberal and puberal goats' ovarian cortex,but no corpus luteum was found in both prepuberal and puberal goats' ovary.Follicles of puberal goats were larger than that of prepuberal goats and filled with granulosa cells.?2?Six small RNA libraries were constrcted by Illumina Solexa sequencing.After date cleaning,a total of 13773420,15120274 and 12113416 clean reads were obtained from puberal goats P₁,P₂ and P₃,accounting for 98.17%,98.05% and 98.07% to the raw reads,respectively;a total of 10101765,11611140 and 11276807 clean reads were obtained from prepuberty goats Pb1,Pb2 and Pb3,accounting for 98.64%,97.42% and96.98% to the raw reads,respectively.?3?The majority of the screened small RNAs that potentially involved in regulating puberty initation range from 20 nt to 24 nt in length and the peak distribution is 22 nt,which respectively accounted for 49.87%,51.65%,49.73% in puberal goats' s RNA libraries P₁,P₂,P₃,and 48.78%,48.39%,50.58% in prepuberal goats' s RNA libraries Pb1,Pb2,Pb3.?4?Compared with mi Rbase 20.0 database,according to the mature and precursor of mi RNA results,a total of 409 known conserved mi RNAs and 117 newly predicted mi RNAs were screened in prepuberal and puberal goats,of which 448 mi RNAs were expressed in both prepuberal and puberal goats' ovaries,21 mi RNAs were specifically expressed in puberal goats' ovaries and 20 mi RNAs were specifically expressed in prepuberal goats' ovaries.?5?30 mi RNAs which significantly differently expressed between prepuberal and puberal goats' ovarian small RNA libraries were screened,of which 9 mi RNAs were significantly upregulated and 21 mi RNAs were significantly downregulated in puberal goats' ovaries.?6?GO annotations indicate the target genes of puberty-regulating mi RNAs were involved a variety of biological processes,such as cellular process,membrance and binding,etc.KEGG pathway analyses indicate that the target genes of puberty-regulating mi RNAs were involved in multiple pathways,most of which were enriched in Olafactory transduction,while others were involved in GABAergic synapse,Oxytocin signaling pathway,Estrogen signaling pathway,Gn RH signaling pathway,c AMP signaling pathway,Progesterone-mediated oocyte maturation,Oocyte meiosis and other pathways may be associated with puberty of goats.?7?7?chi-mi R-182,chi-mi R-655,chi-mi R-3955-5p,chi-mi R-376c-3p,chi-mi R-376e-3p,chi-mi R-136-3p,chi-mi R-423-5p?of 30 significantly differently expressed mi RNAs were subjected to q RT-PCR to test the reliability of the high-throughput sequencing data,and the results verified the reliability of sequencing date.Conclusions: 489 differently expressed ovarian mi RNAs between prepuberal and puberal goats were screened by high-throughput sequencing and bioinformatical analyses,of which9 mi RNAs were sighficantly upregulated and 21 mi RNAs were sighficantly downregulated in puberal goats.The GO and KEGG enrichment analyses indicate that the target genes of differentially expressed mi RNAs were involved in multiple ovarian developmental pathway,such as GABAergic signaling pathway,Oxytocin signaling pathway,c AMP signaling pathway,Progesterone-mediated oocyte maturation and so on.