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Li M, Sun L, Zhou L, Wang D. Tilapia, a good model for studying reproductive endocrinology. Gen Comp Endocrinol 2024; 345:114395. [PMID: 37879418 DOI: 10.1016/j.ygcen.2023.114395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 10/07/2023] [Accepted: 10/21/2023] [Indexed: 10/27/2023]
Abstract
The Nile tilapia (Oreochromis niloticus), with a system of XX/XY sex determination, is a worldwide farmed fish with a shorter sexual maturation time than that of most cultured fish. Tilapia show a spawning cycle of approximately 14 days and can be artificially propagated in the laboratory all year round to obtain genetically all female (XX) and all male (XY) fry. Its genome sequence has been opened, and a perfect gene editing platform has been established. With a moderate body size, it is convenient for taking enough blood to measure hormone level. In recent years, using tilapia as animal model, we have confirmed that estrogen is crucial for female development because 1) mutation of star2, cyp17a1 or cyp19a1a (encoding aromatase, the key enzyme for estrogen synthesis) results in sex reversal (SR) due to estrogen deficiency in XX tilapia, while mutation of star1, cyp11a1, cyp17a2, cyp19a1b or cyp11c1 affects fertility due to abnormal androgen, cortisol and DHP levels in XY tilapia; 2) when the estrogen receptors (esr2a/esr2b) are mutated, the sex is reversed from female to male, while when the androgen receptors are mutated, the sex cannot be reversed; 3) the differentiated ovary can be transdifferentiated into functional testis by inhibition of estrogen synthesis, and the differentiated testis can be transdifferentiated into ovary by simultaneous addition of exogenous estrogen and androgen synthase inhibitor; 4) loss of male pathway genes amhy, dmrt1, gsdf causes SR with upregulation of cyp19a1a in XY tilapia. Disruption of estrogen synthesis rescues the male to female SR of amhy and gsdf but not dmrt1 mutants; 5) mutation of female pathway genes foxl2 and sf-1 causes SR with downregulation of cyp19a1a in XX tilapia; 6) the germ cell SR of foxl3 mutants fails to be rescued by estrogen treatment, indicating that estrogen determines female germ cell fate through foxl3. This review also summarized the effects of deficiency of other steroid hormones, such as androgen, DHP and cortisol, on fish reproduction. Overall, these studies demonstrate that tilapia is an excellent animal model for studying reproductive endocrinology of fish.
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Affiliation(s)
- Minghui Li
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Lina Sun
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Linyan Zhou
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Deshou Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China.
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Yao ZL, Fang QF, Li JY, Zhou M, Du S, Chen HJ, Wang H, Jiang SJ, Wang X, Zhao Y, Ji XS. Alternative splicing of histone demethylase Kdm6bb mediates temperature-induced sex reversal in the Nile tilapia. Curr Biol 2023; 33:5057-5070.e5. [PMID: 37995698 DOI: 10.1016/j.cub.2023.10.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 09/05/2023] [Accepted: 10/23/2023] [Indexed: 11/25/2023]
Abstract
Sex determination in many fish species is remarkably plastic and temperature sensitive. Nile tilapia display a genetic sex-determination system (XX/XY). However, high-temperature treatment during critical thermosensitive periods can induce XX females into XXm pseudo-males, and this phenomenon is termed temperature-induced sex reversal (TISR). To investigate the molecular mechanism of TISR in Nile tilapia, we performed Iso-seq analysis and found a dramatic effect of high temperature on gene alternative splicing (AS). Kdm6bb histone demethylase showed a novel AS at intron 5 that generates Kdm6bb_tv1 transcripts without intron 5 and Kdm6bb_tv2 with intron 5. Kdm6bb_tv1 encodes a full-length protein while Kdm6bb_tv2 encodes a truncated protein. Expression analysis revealed that intron 5 splicing of Kdm6bb is male and gonad biased at larval stage, and only gonad biased at adult stage. High-temperature treatment induced intron 5 splicing in the gonads of XX and XY fish, resulting in increased Kdm6bb_tv1 expression. To directly test the role of Kdm6bb_tv1 in Nile tilapia TISR, we knocked out expression of Kdm6bb_tv1. However, Kdm6bb_tv1-/- homozygous mutants showed embryonic lethality. Overexpression of Kdm6bb_tv1, but not Kdm6bb_tv2, induced sex reversal of XX females into pseudo-males. Overexpression of Kdm6bb_tv1, as with high-temperature treatment, modified the promotor region of Gsdf and Dmrt1 by demethylating the trimethylated lysine 27 of histone 3 (H3K27me3), thereby increasing expression. Collectively, these studies demonstrate that AS of Kdm6bb intron 5 increases the expression of Kdm6bb_tv1, which acts as a direct link between high temperature and activation of Gsdf and Dmrt1 expression, leading to male sex determination.
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Affiliation(s)
- Zhi Lei Yao
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271018, Shandong, China; Key Laboratory of Efficient Utilization of Non-grain Feed Resources (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Shandong Agricultural University, Taian 271018, Shandong, China
| | - Qing Feng Fang
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271018, Shandong, China; Key Laboratory of Efficient Utilization of Non-grain Feed Resources (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Shandong Agricultural University, Taian 271018, Shandong, China
| | - Jia Yue Li
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271018, Shandong, China; Key Laboratory of Efficient Utilization of Non-grain Feed Resources (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Shandong Agricultural University, Taian 271018, Shandong, China
| | - Min Zhou
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271018, Shandong, China; Key Laboratory of Efficient Utilization of Non-grain Feed Resources (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Shandong Agricultural University, Taian 271018, Shandong, China
| | - Shaojun Du
- Department of Biochemistry and Molecular Biology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Hong Ju Chen
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271018, Shandong, China; Key Laboratory of Efficient Utilization of Non-grain Feed Resources (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Shandong Agricultural University, Taian 271018, Shandong, China
| | - Hui Wang
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271018, Shandong, China; Key Laboratory of Efficient Utilization of Non-grain Feed Resources (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Shandong Agricultural University, Taian 271018, Shandong, China
| | - Shi-Jin Jiang
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271018, Shandong, China; Key Laboratory of Efficient Utilization of Non-grain Feed Resources (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Shandong Agricultural University, Taian 271018, Shandong, China
| | - Xiao Wang
- Library, Shandong Agricultural University, Taian 271018, Shandong, China
| | - Yan Zhao
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271018, Shandong, China; Key Laboratory of Efficient Utilization of Non-grain Feed Resources (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Shandong Agricultural University, Taian 271018, Shandong, China.
| | - Xiang Shan Ji
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271018, Shandong, China; Key Laboratory of Efficient Utilization of Non-grain Feed Resources (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Shandong Agricultural University, Taian 271018, Shandong, China.
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Master-Key Regulators of Sex Determination in Fish and Other Vertebrates-A Review. Int J Mol Sci 2023; 24:ijms24032468. [PMID: 36768795 PMCID: PMC9917144 DOI: 10.3390/ijms24032468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/12/2023] [Accepted: 01/25/2023] [Indexed: 02/01/2023] Open
Abstract
In vertebrates, mainly single genes with an allele ratio of 1:1 trigger sex-determination (SD), leading to initial equal sex-ratios. Such genes are designated master-key regulators (MKRs) and are frequently associated with DNA structural variations, such as copy-number variation and null-alleles. Most MKR knowledge comes from fish, especially cichlids, which serve as a genetic model for SD. We list 14 MKRs, of which dmrt1 has been identified in taxonomically distant species such as birds and fish. The identification of MKRs with known involvement in SD, such as amh and fshr, indicates that a common network drives SD. We illustrate a network that affects estrogen/androgen equilibrium, suggesting that structural variation may exert over-expression of the gene and thus form an MKR. However, the reason why certain factors constitute MKRs, whereas others do not is unclear. The limited number of conserved MKRs suggests that their heterologous sequences could be used as targets in future searches for MKRs of additional species. Sex-specific mortality, sex reversal, the role of temperature in SD, and multigenic SD are examined, claiming that these phenomena are often consequences of artificial hybridization. We discuss the essentiality of taxonomic authentication of species to validate purebred origin before MKR searches.
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Curzon AY, Shirak A, Benet-Perlberg A, Naor A, Low-Tanne SI, Sharkawi H, Ron M, Seroussi E. Absence of Figla-like Gene Is Concordant with Femaleness in Cichlids Harboring the LG1 Sex-Determination System. Int J Mol Sci 2022; 23:ijms23147636. [PMID: 35886982 PMCID: PMC9316214 DOI: 10.3390/ijms23147636] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/05/2022] [Accepted: 07/08/2022] [Indexed: 02/04/2023] Open
Abstract
Oreochromis niloticus has been used as a reference genome for studies of tilapia sex determination (SD) revealing segregating genetic loci on linkage groups (LGs) 1, 3, and 23. The master key regulator genes (MKR) underlying the SD regions on LGs 3 and 23 have been already found. To identify the MKR in fish that segregate for the LG1 XX/XY SD-system, we applied short variant discovery within the sequence reads of the genomic libraries of the Amherst hybrid stock, Coptodon zillii and Sarotherodon galilaeus, which were aligned to a 3-Mbp-region of the O. aureus genome. We obtained 66,372 variants of which six were concordant with the XX/XY model of SD and were conserved across these species, disclosing the male specific figla-like gene. We further validated this observation in O. mossambicus and in the Chitralada hybrid stock. Genome alignment of the 1252-bp transcript showed that the figla-like gene’s size was 2664 bp, and that its three exons were capable of encoding 99 amino acids including a 45-amino-acid basic helix–loop–helix domain that is typical of the ovary development regulator—factor-in-the-germline-alpha (FIGLA). In Amherst gonads, the figla-like gene was exclusively expressed in testes. Thus, the figla-like genomic presence determines male fate by interrupting the female developmental program. This indicates that the figla-like gene is the long-sought SD MKR on LG1.
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Affiliation(s)
- Arie Yehuda Curzon
- Institute of Animal Science, Agricultural Research Organization, Rishon LeTsiyon 75288, Israel; (A.Y.C.); (A.S.); (M.R.)
- Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Andrey Shirak
- Institute of Animal Science, Agricultural Research Organization, Rishon LeTsiyon 75288, Israel; (A.Y.C.); (A.S.); (M.R.)
| | - Ayana Benet-Perlberg
- Dor Research Station, Division of Fishery and Aquaculture, Hof HaCarmel 30820, Israel; (A.B.-P.); (A.N.); (S.I.L.-T.); (H.S.)
| | - Alon Naor
- Dor Research Station, Division of Fishery and Aquaculture, Hof HaCarmel 30820, Israel; (A.B.-P.); (A.N.); (S.I.L.-T.); (H.S.)
| | - Shay Israel Low-Tanne
- Dor Research Station, Division of Fishery and Aquaculture, Hof HaCarmel 30820, Israel; (A.B.-P.); (A.N.); (S.I.L.-T.); (H.S.)
| | - Haled Sharkawi
- Dor Research Station, Division of Fishery and Aquaculture, Hof HaCarmel 30820, Israel; (A.B.-P.); (A.N.); (S.I.L.-T.); (H.S.)
| | - Micha Ron
- Institute of Animal Science, Agricultural Research Organization, Rishon LeTsiyon 75288, Israel; (A.Y.C.); (A.S.); (M.R.)
| | - Eyal Seroussi
- Institute of Animal Science, Agricultural Research Organization, Rishon LeTsiyon 75288, Israel; (A.Y.C.); (A.S.); (M.R.)
- Correspondence:
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