犏牛精子发生阻滞的比较转录组研究  

Comparative Transcriptome Analysis of Spermatogenesis Arrest in Cattle-Yak

作　　者：曾贤彬[1] 柴志欣[1] 王永[1] 马志杰[2] 杨琴[1] 宋乔乔[1] 钟金城[1] 

机构地区：[1]西南民族大学青藏高原研究院动物遗传育种学国家民委-教育部共建重点实验室,成都610041 [2]青海省畜牧兽医科学院畜牧研究所,西宁810016

出　　处：《中国科学：生命科学》2014年第6期584-601,共18页Scientia Sinica(Vitae)

基　　金：国家科技支撑计划(批准号:2012BAD13B06);西南民族大学研究生学位点建设项目(批准号:2012XWD-S071007)资助

摘　　要：犏牛是牦牛与普通牛的杂交后代,其雄性不育是牦牛杂交改良中的一大难题.运用高通量测序技术对健康成年犏牛和牦牛的睾丸组织进行转录组测序和比较研究,探讨了犏牛激素调节、精子发生及细胞凋亡等相关基因的表达情况.结果表明,犏牛、牦牛睾丸组织中分别有17784和18529个基因表达,在犏牛中表达显著上调和下调的基因分别有5000和4089个.犏牛睾丸组织中睾酮合成相关基因和抑制素基因表达均显著上调,认为前者的表达上调可能促进睾丸内睾酮分泌和后者的表达,而后者的表达上调可能分别抑制和几乎不影响脑垂体前叶合成、分泌促卵泡刺激素和黄体生成素.比较睾丸组织中细胞标记基因在两种牛间的表达差异,发现犏牛精原干细胞、支持细胞、间质细胞、肌样细胞(睾丸纤维化)和已分化精原细胞的标记基因分别呈显著表达上调和下调,而减数分裂后期或精子形成期呈极显著下调.精原干细胞自我更新与分化异常可能导致犏牛精子发生障碍,认为其与视黄酸信号通路障碍密切相关.Syce3,Fkbp6和Dmrt7等在犏牛睾丸组织中极显著表达下调与同源染色体间、尤其是性染色体间的联会复合体数量减少有关.Spo11和Dmc1分别参与双链断裂和同源修复过程,其在犏牛睾丸中表达下调分别可能使联会复合体减少和同源修复失常.参与高度浓缩细胞核的相关基因,尤其是Tnp2,Hmgb4和H1fnt等几乎不表达,其调控表达基因Crem,GRTH/DDX25等极显著表达下调,该现象与犏牛生精细胞最终只能分化至圆形精子细胞阶段的结果相符.促凋亡相关基因,如p53,TNF-α,Trail,Bmp8b,Bax,Caspase-3,Caspase-6和Caspase-7表达均显著上调,而抑凋亡基因,如survivin,Bcl-2等显著下调,这可能是导致犏牛睾丸组织中有更多的生精细胞发生凋亡的原因之一.通过对生殖相关基因的表达分析研究,为揭示犏牛雄性不育机理以及牦牛�The male infertility of cattle-yak, which is the hybrid offspring of cattle and yak, is a difficult problem for cross-breeding and improvement of yak. In this study, we used high-throughput sequencing technology to obtain the transcriptomes of the testicular tissues of both cattle-yak and yak, and investigated the expression profiles of the genes regulating hormones, spermatogenesis and apoptosis. The results showed that, there were 17784 and 18529 genes expressed in cattle-yak and yak testicular tissues respectively, and statistical analysis revealed 5000 genes with increased mRNA levels and 4089 with reduced levels in cattle-yak testicular tissue as compared with those in yak. The genes involved in testosterone synthesis and inhibin alpha chain have a high level of expression in cattle-yak testicular tissue. The former genes with increased expression may induce the secretion of intratesticular testosterone which can be up-regulated expression of the latter. Inhibin alpha chain with increased mRNA levels possible restrain the secretion of follicle-stimulating hormone of the pituitary gland, but not of luteinizing hormone. This may cause imbalance or deficiency of hormones in cattle-yak which lead to male infertility. By comparing the expression of the testicular marker genes between the two species, we showed that expressions of the marker genes of spermatogonial stem cell, sertoli cell, Leydig cell and myoid cell （fibrosis of testis） are increased, whereas those of differentiation of SSCs （especially those expressed at late stage of spermatid formation） are reduced. The abnormality of self-renewal and differentiation of SSCs, which may be tightly associated with the disorder of retinoic acid signaling pathway, might lead to spermatogenesis dysfunction in cattle-yak. Syce3, Fkbp6 and Dmrt7 are down-regulated significantly in cattle-yak testicular tissue, which may be related with the formation of synaptonemal complex between homologous chromosomes, especially between sex chromosomes. Spo 11 and Dmc1 are

关 键 词：犏牛 牦牛 睾丸 转录组 精子发生 

分 类 号：S858.23[农业科学—临床兽医学]