Effects of 17β-estradiol interference on the temporal and spatial expression patterns of piwil1 gene and gonadal development in largemouth bass (Micropterus salmoides)
摘要
In order to explore the role of piwil1 (Piwi-like RNA-mediated gene silencing 1) in sex differentiation and gonadal development of largemouth bass (Micropterus salmoides). To this end, we established a 17β-estradiol (E2)-treated pseudo-female group (XY-F, sex reversal rate 100%), a control female group (XX-F), and a control male group (XY-M). The full-length cDNA of piwil1 was obtained using the RACE technique, and its expression pattern, response to E2 treatment, and spatial localization were analyzed. The piwil1 cDNA is 3091 bp in length and encodes a protein of 855 amino acids. qRT-PCR showed that piwil1 was highly expressed in the gonads, with higher expression in mature testes than in ovaries (P < 0.05). During early gonadal differentiation, piwil1 expression increased in all groups (XY-M, XX-F, and XY-F). At 2 months old, piwil1 expression was significantly suppressed in E2-treated XY-F fish compared to XY-M and XX-F (P < 0.05). By 12 months old, piwil1 expression was highest in XY-M testes. Fluorescence in situ hybridization (FISH) results confirmed the differential expression pattern of the piwil1 gene, and strong signals were observed in oogonia (OG), primary oocytes (OC1), growing oocytes (GOC), vitellogenic oocytes (VO), primary spermatogonia (PSG), secondary spermatogonia (SSG), primary spermatocytes (PSC), and sperm (SP). In conclusion, piwil1 plays an important role in testis development and spermatogenesis, which exhibits a male-biased expression pattern in largemouth bass. These findings provide a potential molecular target for monosex male breeding in largemouth bass.