Zhang Liyan, Liu Wanjun, Shao Changwei, Zhang Ning, Li Hailong, Liu Kun, Dong Zhongdian, Qi Qian, Zhao Wen, Chen Songlin
College of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China; Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China.
Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Fisheries College, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
Mar Genomics. 2014 Dec;18 Pt A:45-54. doi: 10.1016/j.margen.2014.04.004. Epub 2014 May 1.
piwi is an important regulator gene in germ cell division during spermatogenesis. piwi homologous genes are involved in gametogenesis and germline specification, and knocking down these genes could affect germ cell meiotic progression. To understand the function of piwi-related genes in spermatogenesis, we cloned a Piwi-subfamily member (piwil2 gene) from the gonad of Cynoglossus semilaevis. The full-length of piwil2 cDNA was 3314bp, including a 3162bp open reading frame (ORF), a 60bp 5'-UTR, along with a 92bp 3'-UTR, and encoded a predicted protein of 1053 amino acid residues. Phylogenetic analysis showed that the PIWIL2 putative protein belonged to the Argonaute protein family, and Piwi-subfamily, with typical PAZ and Piwi domains. Ultrathin sections of different gonadal stages, and real-time quantitative PCR showed that the relative expression of the piwil2 gene couldn't be detected until day 95 (95days) larvae, when germ cell divided rapidly in C. semilaevis. The piwil2 transcripts were more abundant in gonads of males and neo-males than in females, and weakly expressed in other tissues and organs. Compared with the relative expression of piwil2 in gonads, the CpG methylation levels were significantly higher in females. Chromosomal fluorescence in situ hybridization (FISH) showed that the piwil2 gene was located on the Z sex chromosome of C. semilaevis. These results suggest that piwil2 plays an important role in spermatogenesis of C. semilaevis.
Piwi是精子发生过程中生殖细胞分裂的重要调控基因。Piwi同源基因参与配子发生和生殖系特化，敲低这些基因会影响生殖细胞减数分裂进程。为了解Piwi相关基因在精子发生中的功能，我们从半滑舌鳎性腺中克隆了一个Piwi亚家族成员（piwil2基因）。piwil2 cDNA全长3314bp，包括一个3162bp的开放阅读框（ORF）、一个60bp的5'-UTR以及一个92bp的3'-UTR，编码一个预测的含1053个氨基酸残基的蛋白质。系统发育分析表明，PIWIL2推定蛋白属于AGO蛋白家族的Piwi亚家族，具有典型的PAZ和Piwi结构域。不同性腺发育阶段的超薄切片及实时定量PCR结果显示，在半滑舌鳎中，直到95日龄幼虫时生殖细胞快速分裂，才能检测到piwil2基因的相对表达。piwil2转录本在雄性和新雄性性腺中的丰度高于雌性，在其他组织和器官中表达较弱。与性腺中piwil2的相对表达相比，雌性中的CpG甲基化水平显著更高。染色体荧光原位杂交（FISH）表明，piwil2基因位于半滑舌鳎的Z性染色体上。这些结果表明，piwil2在半滑舌鳎的精子发生中起重要作用。
