简州大耳羊早期胎儿到新出生阶段背最长肌中可变剪接的鉴定与分析

摘要

可变剪接广泛存在于动植物的各个组织中,是形成动植物体内蛋白质多样性和复杂性的重要机制之一.以简州大耳羊为研究对象,采集母羊妊娠期第45天、60天、105天胎儿以及出生后第3天羔羊的背最长肌组织,进行转录组测序.测序数据经比对、组装后,共鉴定出来自于4 562个(16.77％)已注释基因的137 308个可变剪接事件.其中,所占比例最高的类型为外显子跳跃(30.64％),而3′端可变剪接位点、内含子保留、5′端可变剪接位点的比例分别为19.47％、18.07％和10.92％.对RBMs、HNRNPs和SRSFs 3类可变剪接调控因子中58个基因表达量分析表明,19个基因的表达量呈现显著差异(P＜0.05);其中15个基因在妊娠期第45天和第60天的表达量显著高于其他2个阶段.GO功能注释和富集分析结果表明,4个阶段均发生可变剪接的基因显著富集在细胞表达调控和物质合成等过程(P＜0.05).值得注意的是,在妊娠期第60天,可变剪接事件、可变剪接基因的数量和可变剪接因子表达量均显著高于其他阶段,并且特异性基因显著富集在有丝分裂和大分子合成相关过程.上述结果表明,妊娠期第60天胎儿的成肌过程非常活跃,暗示可变剪接在山羊背最长肌发育过程中具有重要作用,为深入探索可变剪接在山羊肌肉发育中的作用提供理论依据.%Alternative splicing(AS) events exist extensively at a variety of tissues in plants and animals,which is one of the most important molecular mechanisms underlying diversity and complexity of proteins.Based on the transcriptome sequence data in Jianzhou Da'er goat,we systematically investigated AS patterns and explored their potential functions in Longissimus dorsi sampled from the fetus on days 45,60,and 105 of gestation and the lambs on the third day after born,respectively.Accordingly,a total of 137 308 AS events from 4 562 genes were identified at four goat skeletal myogenesis stages.The largest proportion of the total AS events was exon skipping(30.64％),and alternative 3'splice site,intron retention,alternative 5'splice site accounted for 19.47％,18.07％ and 10.92％,respectively.Of the 58 genes from the RBMs,HNRNPs and SRSFs families,in addition,19 genes showed significantly differential expressions across the four stages (P ＜ 0.05).The GO enrichment analysis displayed that the overlapped AS genes across the four stages were significantly enriched in the cell expression regulation process and macromolecular synthesis(P＜0.05).Obviously,the number of the AS events and genes,and the expression levels of the splicing factors on the day 60 of gestation were significantly higher than those at other stages.The GO enrichment analysis further revealed that the unique AS genes were significantly enriched in mitosis and macromolecular synthesis related processes (P＜0.05),indicating that these AS events played important roles during the Longissimus dorsi myogenesis.Therefore,this study provides theoretical reference for exploring the functions of alternative splicing in goat muscle development.