过表达miR-9对黄鳝受精卵中基因转录组水平的影响

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

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。

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.