Li Xixi, Lin Siyu, Fan Shutong, Huang Xiaoting, Zhang Zhifeng, Qin Zhenkui
Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya 572000, China.
Biology (Basel). 2022 Mar 16;11(3):456. doi: 10.3390/biology11030456.
Research on expressional regulation of genes at the initial sex differentiation of gonads will help to elucidate the mechanisms of sex determination and differentiation in animals. However, information on initial sex differentiation of gonads is limited in bivalves. MicroRNAs (miRNAs) are a class of endogenous small noncoding RNAs that can regulate the target gene expression at the posttranscription level by degrading the mRNA or repressing the mRNA translation. In the present study, we investigated the small RNAs transcriptome using the testes and ovaries of Zhikong scallop Chlamys farreri juveniles with a shell height of 5.0 mm, a critical stage of initial sex differentiation of gonads. A total of 75 known mature miRNAs and 103 novel miRNAs were identified. By comparing the expression of miRNAs between the ovary and testis, 11 miRNAs were determined to be differentially expressed. GO annotations and KEGG analyses indicated that many putative target genes that matched to these differentially expressed miRNAs participated in the regulation of sex differentiation. Furthermore, two selected miRNAs, cfa-novel_miR65 and cfa-miR-87a-3p_1, were confirmed to downregulate expressions of (a female-critical gene) and (a male-critical gene), respectively, using a dual-luciferase reporter analysis. Our findings provided new insights into the initial sex differentiation of gonads regulated by miRNAs in bivalves.
对性腺初始性别分化过程中基因表达调控的研究，将有助于阐明动物性别决定和分化的机制。然而，双壳贝类性腺初始性别分化的相关信息有限。微小RNA（miRNA）是一类内源性小非编码RNA，可通过降解mRNA或抑制mRNA翻译在转录后水平调控靶基因表达。在本研究中，我们利用壳高5.0毫米的栉孔扇贝稚贝的精巢和卵巢，这是性腺初始性别分化的关键阶段，对小RNA转录组进行了研究。共鉴定出75个已知成熟miRNA和103个新miRNA。通过比较卵巢和精巢中miRNA的表达，确定了11个差异表达的miRNA。基因本体（GO）注释和京都基因与基因组百科全书（KEGG）分析表明，许多与这些差异表达miRNA匹配的假定靶基因参与了性别分化的调控。此外，使用双荧光素酶报告分析证实，两个选定的miRNA，即cfa-novel_miR65和cfa-miR-87a-3p_1，分别下调了（一个雌性关键基因）和（一个雄性关键基因）的表达。我们的研究结果为双壳贝类中miRNA调控性腺初始性别分化提供了新的见解。
