Characterization of the Nanog gene involved in the gonadal development in pearlscale angelfish (Centropyge vrolikii)

Expression and localization of Cyclin D1/Nanog and NF-κB/Bax protein in dysplastic testicles of mice

Testicular dysplasia significantly impairs male reproductive capacity. This study investigated the expression of Cyclin D1/Nanog and NF-κB/Bax in dysplastic testes of mice using histological staining, Western blotting, and immunohistochemistry. The results showed that Nanog and Bax expression were significantly higher in dysplastic testicular tissue than in normal tissue (P < 0.01). Cyclin D1 protein expression was higher in normal testis tissue than in dysplastic testis (P < 0.01). NF-κB was highly expressed in cryptorchid and normal testis with no significant difference (P > 0.05). Immunolocalization revealed that Nanog, NF-κB, and Bax were expressed in the cytoplasm of Leydig and spermatogenic cells. Cyclin D1 primarily expressed in the nucleus of Sertoli cells. These findings suggest that altered expression of Nanog, Cyclin D1, and Bax may contribute to testicular dysplasia. This study provides a scientific foundation for detecting testicular dysplasia and selecting appropriate animal models, ultimately informing strategies to improve male reproductive health.

Expression pattern analysis of anti-Mullerian hormone in testis development of pearlscale angelfish (Centropyge vrolikii)

In vertebrates, anti-Mullerian hormone (Amh) secreted by Sertoli cells (SC) performs a pivotal function in male sex differentiation. Compared with that of higher vertebrates, the expression pattern of Amh is more diversified in fish. In this study, the full-length complementary DNA (cDNA) of Amh in Centropyge vrolikii (Cv-Amh) was cloned and analysed, which was 2,470 bp, including a 238 bp 5'UTR, a 1,602 bp ORF and a 633 bp 3'UTR; the similarity of Amh between Cv-Amh and other fish is relatively high. The quantitative real-time PCR (qRT-PCR) results of healthy tissues and gonads at sex reversal stages in C. vrolikii showed that the expression level of Amh in the testis was significantly higher than that in other tissues (P < 0.05). Amh was weakly expressed in the vitellogenic stage ovary and perinucleolus stage ovary, but its expression significantly increased in the gonads at the hermaphroditic stage, and finally reached the highest in the pure testis after sexual reversal. The results of in situ hybridization indicated that the positive signal of Amh was strongly concentrated in SCs of testis. After Amh knockdown in the gonads, the effect on sex-related genes was tested using qRT-PCR. Among these, the expression of Dmrt1, Cyp11a, Hsd11b2, Sox8 and Sox9 significantly decreased, whereas that of Cyp19a, Sox4, Foxl2 and Sox3 increased. These results suggested that Amh could be the pivotal gene in reproductive regulation in C. vrolikii, and the data will contribute to sex-related research of C. vrolikii in the future.

The molecular regulation mechanism of dmrt1-based on the establishment of the testis cell line derived from two-spot puffer Takifugu bimaculatus

The establishment of fish cell lines can provide an important in vitro model for developmental biology, pathology, and genetics and also an effective tool to investigate the interactions and related functions of genes. Two-spot puffer Takifugu bimaculatus is a high economic and nutritional value marine fish in Fujian in recent years. Nevertheless, dmrt1 plays a key role in the male differentiation from invertebrates to vertebrates. To understand the molecular regulatory mechanisms of dmrt1 in T. bimaculatus, a testis cell line called TBTc from a juvenile testis of this organism was established with modified Leibovitz's L-15 medium supplemented with 20% FBS, fish serum, embryo extract, and other growth factors. The TBTc with a stable karyotype can be passaged continuously, which was composed of fibroblast-like cells and expressed the marker genes of male-special cells, dmrt1, and amh, and the absence of vasa expression may rule out the possibility of the presence of germ cells. Therefore, TBTc appeared to consist of the mixture of the Sertoli cell and germ cell of the testis. The dmrt1 was significantly expressed in the testes and slightly expressed in the late embryonic development, illustrating that the dmrt1 may participate in the molecular regulation of gonads development and sex differentiation. With the high transfection efficiency of TBTc by electroporation, the cell lines could be used effectively in the study for the expression of exogenous and endogenous genes. Meanwhile, after the knockdown of dmrt1, the morphological changes and survival rates of cells proved that dmrt1 could affect the growth of testicular cells. Furthermore, with the loss of dmrt1, the expression of male-bias genes amh, sox9, and cyp11a was significantly decreased, and the expression of female-bias genes foxl2, sox3, and cyp19a was increased, which suggested that dmrt1 upregulates amh, sox9, and cyp11a and downregulates foxl2, sox3, and cyp19a to participate in the testis development. As a first fish gonadal cell lines of T. bimaculatus, which can be a more convenient, efficient, and rapid model for the investigation of the expression and function of genes, the results will lay a foundation for the next study of the molecular regulation mechanism in gonadal development and sex determination of fish in the future.