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Largemouth bass (Micropterus salmoides) is an economically important fish. It can spawn many times during a breeding season, and there are no obvious morphological characteristics to distinguish male and female juvenile fish. So far, little is known about the genes regulating their sexual development in this species. Here, we performed RNA sequenci...
Citations
... In Hong Kong catfish (Clarias fuscus), many differentially expressed genes (DEGs) were found to be enriched using sex-related gene ontology (GO) terms and analysis through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, such as oocyte maturation, androgen secretion, gonadal development and steroid biosynthesis [9]. The dmrt1 gene has been revealed to play a dual role during testicular development in largemouth bass (Micropterus salmoides) [10]. In sea urchin (Strongylocentrotus intermedius), five DEGs related to gonadal quality have been identified [11]. ...
Simple Summary
Brachymystax tsinlingensis Li has become an endangered species due to human activities and habitat degradation. However, little is known about the genes regulating its gonadal development. This study presents a high-quality gonadal transcriptome of B. tsinlingensis Li. A total of 22,864 differentially expressed genes between male and female were identified. Numerous sex-related differentially expressed genes, such as ccnb1, zp3, bmp15, dmrt1, and psmc3ip, were identified. Some signaling pathways involved in gonadal development, such as genes involved in base excision repair, the notch signaling pathway, neuroactive ligand-receptor interaction, the VEGF signaling pathway, and the estrogen signaling pathway, were found to be enriched through analysis using the Kyoto Encyclopedia of Genes and Genomes. Our results provide molecular data to support a better understanding of sexual development in B. tsinlingensis Li.
Abstract
Brachymystax tsinlingensis Li is an endangered cold-water salmonid fish native to China. This study aimed to identify sex-related genes and biological pathways via gonadal transcriptome sequencing of B. tsinlingensis Li. A total of 167,904 unigenes were identified with an average length of 836 bp and an N50 of 1452 bp, of which 84,977 (50.61%) unigenes were successfully annotated in six major databases. Comparative transcriptome analysis identified 22,864 differentially expressed genes (DEGs), of which 17,231 were up-regulated (male-biased genes, mDEGs) and 5633 were down-regulated (female-biased genes, fDEGs). Several DEGs associated with gonadal development were found through Gene Ontology enrichment analysis, such as ccnb1, zp3, bmp15, dmrt1, and psmc3ip. Signaling pathways related to gonadal development were found to be enriched through analysis using the Kyoto Encyclopedia of Genes and Genomes Pathway database, such as genes involves in base excision repair, the notch signaling pathway, neuroactive ligand-receptor interaction, the VEGF signaling pathway, and the estrogen signaling pathway. In addition, mRNA expression levels of 19 DEGs were determined to validate the reliability of the transcriptomic data by quantitative real-time polymerase chain reaction. These results revealed genes and signaling pathways potentially involved in gonadal development in B. tsinlingensis Li and provided basic molecular data for future research on reproductive regulation and breeding of B. tsinlingensis Li.
... anchovy, sardine and round herring), which play a key role in the food chain and energy flow. Anchovies (Engraulis sp.) are small the reproductive biology of teleosts [14][15][16]. In particular, the ovary is known to be one of the most active organs for cell division, differentiation and maturation in an adult fish body [17][18][19][20]. ...
European anchovy is a multiple-spawning and highly fecundate pelagic fish with high economic and ecological significance. Although fecundity is influenced by nutrition, temperature and weight of spawners, high reproductive capacity is related to molecular processes in the ovary. The ovary is an essential and complex reproductive organ composed of various somatic and germ cells, which interact to facilitate the development of the ovary and functional oocytes. Revealing the ovarian transcriptome profile of highly fecundate fishes provides insights into oocyte production in teleosts. Here we use a comprehensive tissue-specific RNA sequencing which yielded 102.3 billion clean bases to analyze the transcriptional profiles of the ovary compared with other organs (liver, kidney, ovary, testis, fin, cauda and gill) and juvenile tissues of European anchovy. We conducted a comparative transcriptome and positive selection analysis of seven teleost species with varying fecundity rates to identify genes potentially involved in oogenesis and oocyte development. Of the 2,272 single copies of orthologous genes found, up to 535 genes were under positive selection in European anchovy and these genes are associated with a wide spectrum of cellular and molecular functions, with enrichments such as RNA methylation and modification, ribosome biogenesis, DNA repair, cell cycle processing and peptide/amide biosynthesis. Of the 535 positively selected genes, 55 were upregulated, and 45 were downregulated in the ovary, most of which were related to RNA and DNA transferase, developmental transcription factors, protein kinases and replication factors. Overall, our analysis of the transcriptome level in the ovarian tissue of a teleost will provide further insights into molecular processes and deepen our genetic understanding of egg production in highly fecund fish.
... The dmrt1 and sox9 genes have a well-conserved function related to testis formation in vertebrates (Adolfi et al. 2015), and dmrt1 binds with sox9, which then cooperates to reprogram sexual cell fate and participates in testicular differentiation (Berbejillo et al. 2013;Lindeman et al. 2021). The testis-specific dmrt1 can play a dual role by inducing the testis-biased genes (cyp11b1 and spata4) and inhibiting the ovary-biased genes (foxl2, gdf9, zp3, sox3, cyp19a, and bmp15) during the testicular development (Guan et al. 2022). And dmrt1, sox9, and amh were significantly expressed in the testes, regulating testis' development together (Zhong et al. 2021). ...
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.
