过表达miR-9对黄鳝受精卵中基因转录组水平的影响

为了更深入地研究鱼类天然性逆转的生理学机制, 研究通过克隆黄鳝(Monopterus albus) miR-9的前体序列, 及在黄鳝受精卵中过表达miR-9的生物学研究, 最终筛选得到157个基因与miR-9的过表达相关, 其中松弛素信号通路(ko04926)为显著富集的KEGG条目。tektin 4基因(tekt4)、环腺苷酸环化酶合成酶2a(adcy2a)、Ⅰ型细胞骨架角蛋白13(k1c13)和视黄醇脱氢酶5(rdh5)等基因的表达量在miR-9过表达后出现不同程度的升高; 成纤维细胞生长因子13b(fgf13b)和促甲状腺激素释放激素受体2(trhr2)等基因的表达量在miR-9过表达后出现不同程度的降低。rdh5基因在黄鳝眼睛中具有最高的表达水平(P<0.01), 而在脑、血液、精巢和卵巢中几乎没有表达(P<0.01)。松弛素家族基因rln3a和rln3b在黄鳝成鱼中的组织表达模式类似, 均在脑和精巢组织中具有较高的表达水平。推测miR-9可能与黄鳝视觉功能的发育或维持相关; miR-9可能通过松弛素信号通路调控黄鳝精巢的发育过程。研究有助于探讨miR-9对内分泌系统相关基因的调控通路, 为阐明黄鳝性别分化的分子机制提供理论依据。

MIR-9 OVEREXPRESSION ON TRANSCRIPTOME LEVEL IN FERTILIZED EGGS OF MONOPTERUS ALBUS

During fish sexual differentiation, microRNA (miRNA) plays an important regulatory role in the germ cells development. Previous studies showed that miR-9 might promote spermatogenesis during the natural sex reversal in the rice field eel (Monopterus albus). In this study, we cloned the precursor sequence of miR-9 and overexpressed miR-9 in the fertilized eggs of rice field eel. Finally, we screened 157 genes to be associated with miR-9 overexpression after RNA-seq. Relaxin signaling pathway (ko04926) was one of the significantly enriched KEGG term. The expression of tekt4, adcy2a, k1c13 and rdh5 was up-regulated after overexpressed miR-9; the expression of fgf13b and trhr2 was down-regulated after overexpressed miR-9 in the fertilized eggs of rice field eel. The retinol dehydrogenase 5 (rdh5) had the highest expression level in the eyes of rice field eel (P<0.01), whereas almost no expression in the brain, blood, testis and ovaries (P<0.01). The relaxin family genes, rln3a and rln3b, had similar tissue expression patterns in rice field eel, both with high expression levels in the brain and testis. We speculated that miR-9 might be associated with the development or maintenance of visual function in rice field eel; miR-9 may regulate the testis developmental of rice field eel through the relaxin signaling pathway. This study is helpful to further analyze regulation pathway of miR-9 on genes related to endocrine system, and provides theoretical evidence for sexual differentiation in the rice field eel.