不同繁殖季节绵羊卵巢组织中piRNAs序列特征及表达差异分析

Characterization and Differentially Expression Analysis of Ovine Ovary piRNAs During Different Reproductive Seasons

为了分析绵羊卵巢组织中piRNAs的序列特征及不同繁殖季节绵羊卵巢组织中piRNAs的表达差异,本试验采用Solexa测序技术对休情季节(休情期)和发情季节(卵泡期和黄体期)滩羊卵巢组织进行高通量测序,采用生物信息学方法筛选绵羊卵巢中的piRNAs,对piRNAs的长度分布、首位碱基偏好、基因组来源、染色体分布、链特异性、ping-pong循环特征、piRNAs比对重复序列类型进行分析,并对发情季节与休情季节绵羊卵巢之间差异表达的piRNAs进行靶基因预测及其靶基因的GO功能和KEGG Pathway富集分析。结果显示,绵羊卵巢中不同长度的piRNAs首位碱基偏好性不一致;3个时期(休情期、黄体期和卵泡期)的piRNAs均主要比对到基因内含子、编码区及lncRNA区域,而比对到重复序列的piRNAs相对较少;绵羊卵巢piRNAs在染色体上呈不均匀分布;绵羊piRNAs簇存在很强的链特异性,但首位碱基偏好性不明显;3个时期的piRNAs均无明显的ping-pong循环特征。KEGG富集分析发现,差异piRNA靶基因主要富集在RNA运输通路(RNA transport pathway)、嘌呤代谢通路(purine metabolism pathway)、黏着斑通路(focal adhesion)、PI3K-Akt信号通路(PI3K-Akt signaling pathway)、Hippo信号通路(Hippo signaling pathway)等与绵羊繁殖相关的通路。本研究揭示了不同繁殖季节绵羊卵巢组织中的piRNAs序列特征,暗示绵羊卵巢组织中的piRNAs可能通过BAD等基因和黏着斑通路等调控绵羊季节性繁殖,为深入解析绵羊季节性发情分子机制提供一定参考。

In order to analyze the sequence features of piRNAs and the expression difference of piRNAs between anestrus and estrus season in ovine ovary,Solexa high-throughput sequencing technology was used in ovary tissue of Tan sheep during the anestrous and estrus season(include follicular and luteal phases).Then piRNAs in ovine ovary were screened,and the length distribution,the first base bias,genomic distribution,chromosome distribution,strand specificity and ping-pong signature of piRNAs and the types of repetitive sequence which piRNAs mapped to were analyzed by bioinformatics methods.The differentially expressed piRNAs(DE piRNAs)in ovary of Tan sheep between anestrus and estrus season were screened and the target gene of DE piRNAs were subjected to GO and KEGG analysis.The results showed that the first base of different size piRNAs in ovine ovary were various.All of the piRNAs from three stages were mainly mapped to intron,coding sequence and lncRNA while little mapped to repeat sequences.The distribution of piRNAs in ovary were uneven among the chromosomes.piRNAs in ovine ovary had strong strand specificity.piRNAs from three stages had no obvious ping-pong signature.The KEGG enrichment analysis showed that the target genes of DE piRNAs were mainly enriched in those pathways that were correlated with ovine reproduction,such as RNA transport pathway,purine metabolism pathway,focal adhesion,PI3K-Akt signaling pathway and Hippo signaling pathway and so on.In conclusion,the characters of piRNAs from ovine ovary during different reproductive stages were revealed,the results suggested that piRNAs in sheep ovarian tissue might participate in regulation of seasonal reproduction through target genes such as BAD and pathways such as focal adhesion,which provided some reference for further analysis of the molecular mechanism of sheep seasonal estrus.