Roles of forkhead box protein L2 (foxl2) during gonad differentiation and maintenance in a fish, the olive flounder (Paralichthys olivaceus)

2019 ◽  
Vol 31 (11) ◽  
pp. 1742 ◽  
Author(s):  
Zhaofei Fan ◽  
Yuxia Zou ◽  
Dongdong Liang ◽  
Xungang Tan ◽  
Shuang Jiao ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cytochrome P450 ◽  
High Temperature ◽  
Paralichthys Olivaceus ◽  
Sex Reversal ◽  
Olive Flounder ◽  
Gonad Differentiation ◽  
Forkhead Box ◽  
Cytochrome P450 Family ◽  
Olive Flounder Paralichthys Olivaceus

As an important maricultured fish, the olive flounder Paralichthys olivaceus shows sex-dimorphic growth. Thus, the molecular mechanisms involved in sex control in P. olivaceus have attracted researchers’ attention. Among the sex-related genes, forkhead box protein L2 (foxl2) exhibits significant sex-dimorphic expression patterns and plays an important role in fish gonad differentiation and development. The present study first investigated the expression levels and promoter methylation dynamics of foxl2 during flounder gonad differentiation under treatments of high temperature and exogenous 17β-oestradiol (E2). During high temperature treatment, the expression of flounder foxl2 may be repressed via maintenance of DNA methylation. Then, flounder with differentiated testis at Stages I–II were treated with exogenous 5ppm E2 or 5ppm E2+150ppm trilostane (TR) to investigate whether exogenous sex hormones could induce flounder sex reversal. The differentiated testis exhibited phenotypic variations of gonadal dysgenesis with upregulation of female-related genes (foxl2 and cytochrome P450 family 19 subfamily A (cyp19a)) and downregulation of male-related genes (cytochrome P450 family 11 subfamily B member 2 (cyp11b2), doublesex- and mab-3 related transcription factor 1 (dmrt1), anti-Mullerian hormone (amh) and SRY-box transcription factor 9 (sox9)). Furthermore, a cotransfection assay of the cells of the flounder Sertoli cell line indicated that Foxl2 was able alone or with nuclear receptor subfamily 5 group A member 2 (Nr5a2) jointly to upregulate expression of cyp19a. Moreover, Foxl2 and Nr5a2 repressed the expression of dmrt1. In summary, Foxl2 may play an important role in ovarian differentiation by maintaining cyp19a expression and antagonising the expression of dmrt1. However, upregulation of foxl2 is not sufficient to induce the sex reversal of differentiated testis.

scholarly journals Characteristics of Cyp11a during Gonad Differentiation of the Olive Flounder Paralichthys olivaceus

2018 ◽  
Vol 19 (9) ◽  
pp. 2641 ◽  
Author(s):  
Dongdong Liang ◽  
Zhaofei Fan ◽  
Yuxia Zou ◽  
Xungang Tan ◽  
Zhihao Wu ◽  
...  
Keyword(s):  
Treatment Group ◽  
Paralichthys Olivaceus ◽  
Expression Patterns ◽  
Head Kidney ◽  
Adenosine Monophosphate ◽  
Expression Level ◽  
Olive Flounder ◽  
High Temperature Treatment ◽  
Gonad Differentiation ◽  
Olive Flounder Paralichthys Olivaceus

The P450 side-chain cleavage enzyme, P450scc (Cyp11a) catalyzes the first enzymatic step for the synthesis of all steroid hormones in fish. To study its roles in gonads of the olive flounder Paralichthys olivaceus, an important maricultured fish species, we isolated the cyp11a genomic DNA sequence of 1396 bp, which consists of 5 exons and 4 introns. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) results indicated that the flounder cyp11a was exclusively expressed in gonad and head kidney tissues. Its expression level in the testis was higher than that in the ovary. According to the in situ hybridization patterns, cyp11a was mainly expressed in the Leydig cells of the testis, and the thecal cells of the ovary. Immunofluorescence analysis showed that Cyp11a was located in the cytoplasm of the cultured flounder testis cells. Further quantitative real-time PCR results presented the cyp11a differential expression patterns during gonad differentiation. Among different sampling points of the 17β-estradiol (E2, 5 ppm) treatment group, cyp11a expression levels were relatively high in the differentiating ovary (30 and 40 mm total length, TL), and then significantly decreased in the differentiated ovary (80, 100 and 120 mm TL, p < 0.05). The pregnenolone level also dropped in the differentiated ovary. In the high temperature treatment group (HT group, 28 ± 0.5 °C), the cyp11a expression level fluctuated remarkably in the differentiating testis (60 mm TL), and then decreased in the differentiated testis (80, 100 mm TL, p < 0.05). In the testosterone (T, 5 ppm) treatment group, the cyp11a was expressed highly in undifferentiated gonads and the differentiating testis, and then dropped in the differentiated testis. Moreover, the levels of cholesterol and pregnenolone of the differentiating testis in the HT and T groups increased. The expression level of cyp11a was significantly down-regulated after the cultured flounder testis cells were treated with 75 and 150 μM cyclic adenosine monophosphate (cAMP), respectively (p < 0.05), and significantly up-regulated after treatment with 300 μM cAMP (p < 0.05). Both nuclear receptors NR5a2 and NR0b1 could significantly up-regulate the cyp11a gene expression in a dosage dependent way in the testis cells detected by cell transfection analysis (p < 0.05). The above data provides evidence that cyp11a would be involved in the flounder gonad differentiation and development.

scholarly journals Haploinsufficiency of SF-1 Causes Female to Male Sex Reversal in Nile Tilapia, Oreochromis niloticus

Endocrinology ◽  
2016 ◽  
Vol 157 (6) ◽  
pp. 2500-2514 ◽  
Author(s):  
Qing-Ping Xie ◽  
Xue He ◽  
Yi-Ning Sui ◽  
Li-Li Chen ◽  
Li-Na Sun ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Gonadal Dysgenesis ◽  
Nile Tilapia ◽  
Sex Reversal ◽  
Efferent Duct ◽  
Forkhead Box ◽  
Male Sex ◽  
Steroidogenic Cells ◽  
Cytochrome P450 Family ◽  
Estradiol 17Β

Steroidogenic factor-1 (Sf-1) (officially designated nuclear receptor subfamily 5 group A member 1 [NR5A1]) is a master regulator of steroidogenesis and reproduction in mammals. However, its function remains unclear in nonmammalian vertebrates. In the present study, we used immunohistochemistry to detect expression of Sf-1 in the steroidogenic cells, the interstitial, granulosa, and theca cells of the ovary, and the Leydig cells of the testis, in Nile tilapia. Clustered regularly interspaced short palindromic repeats/CRISPR associated protein 9 (Cas9) cleavage of sf-1 resulted in a high mutation rate in the F0 generation and a phenotype of gonadal dysgenesis and reduced steroidogenic cells in XX and XY fish. Sf-1 deficiency also resulted in decreased cytochrome P450, family 19, subfamily A, polypeptide 1a, forkhead box L2 expression, and serum estradiol-17β in XX fish. In XY fish, Sf-1 deficiency increased cytochrome P450, family 19, subfamily A, polypeptide 1a and forkhead box L2 expression but decreased cytochrome P450, family 11, subfamily B, polypeptide 2 expression and serum 11-ketotestosterone levels. 17α-methyltestosterone treatment successfully rescued the gonadal phenotype of Sf-1-deficient XY fish, as demonstrated by normal spermatogenesis and production of F1 mutants. In contrast, estradiol-17β treatment only partially rescued the gonadal phenotype of Sf-1-deficient XX fish, as demonstrated by the appearance of phase II oocytes. Furthermore, both sf-1+/− F1 XX and XY mutants developed as fertile males, although spermatogenesis was delayed and efferent duct formation was disordered. Our data suggest that Sf-1 is a major regulator of steroidogenesis and reproduction in fish, as it is in mammals. Sf-1 deficiency resulted in gonadal dysgenesis and feminization of XY gonads. However, unlike in mammals, Sf-1 deficiency also resulted in female to male sex reversal in 8.1% of F0 and 92.1% of sf-1+/− F1 in XX fish.

scholarly journals Mealworm, Tenebrio molitor, as a feed ingredient for juvenile olive flounder, Paralichthys olivaceus

2021 ◽  
Vol 20 ◽  
pp. 100747
Author(s):  
Seong-Mok Jeong ◽  
Sanaz Khosravi ◽  
Kye-Yoon Yoon ◽  
Kang-Woong Kim ◽  
Bong-Joo Lee ◽  
...  
Keyword(s):  
Paralichthys Olivaceus ◽  
Tenebrio Molitor ◽  
Olive Flounder ◽  
Feed Ingredient ◽  
Olive Flounder Paralichthys Olivaceus
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