Effect of methyl testosterone- and ethynyl estradiol-induced sex differentiation on catfish, Clarias gariepinus: expression profiles of DMRT1, Cytochrome P450aromatases and 3 β-hydroxysteroid dehydrogenase

Kavarthapu, Raghuveer; Garhwal, R; Wang, D S; Bogerd, Jan; Kirubagaran, R.; Rasheeda, M. K.; Sreenivasulu, G.; Bhattachrya, N; Tarangini, S; Nagahama, Yoshitaka; Senthilkumaran, B.

doi:10.1007/s10695-006-0016-3

Cited by 21 publications

(15 citation statements)

References 6 publications

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“…Then, the question was changed into whether MT treatment was unable to induce sex reversal in all catfishes. Contrary to our expectation, there were reports demonstrating that MT could successfully induce female-to-male sex reversal in catfishes, such as African catfish (Clarias gariepinus) ( Van der Hurk et al 1989;Liu and Yao 1996;Raghuveer et al 2006;Raghuveer and Senthilkumaran 2009) and in Heteropneustes fossilis (Haniffa et al 2004), even though it could not in some other catfishes, such as channel catfish (Ictalurus punctatus) (Davis et al 1990), blue catfish (Ictalurus furcatus) (Davis et al 1992) and Thai walking catfish (Na-Nakorn et al 1993). These paradoxical results questioned the rationality of our speculation.…”

Section: Discussioncontrasting

confidence: 86%

Isolation, sequence analysis, and characterization of androgen receptor in Southern catfish, Silurus meridionalis

Huang

Sun

et al. 2010

Fish Physiol Biochem

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Androgen receptor (AR), the mediator of androgen, plays important roles in the androgen signal pathway. In the present study, we isolated and analyzed the cDNA sequence and tissue distribution of androgen receptor in Southern catfish (scAR). The full-length cDNA of scAR contains 3,116 bp with an open reading frame (ORF) of 2,415 bp, encoding a protein of 804 amino acids (aa). Tissue distribution analysis of scAR revealed that it was expressed in all tissues examined, with no sexual dimorphism in the ovary and testis. Phylogenetic analysis and multiple amino acids sequence alignment indicated the close relationship and high similarity of scAR with ARs from cypriniform species. In addition, partial sequences of ARs from 7 other siluriform species were also isolated. Comparison of catfish ARs with those from other vertebrates revealed that an extra C-terminal tail of about 20aa exists in all the ARs from siluriform fishes investigated, but not in other ARs. The extra sequence was resulted from a 4-bp insertion before the stop codon of other vertebrate ARs, and it was identical in ARs from siluriform species of the same genus but different among ARs from species of different genera. We report here for the first time that the ARs from siluriform species are longer in C-terminal than those from other vertebrates and it might be useful in reconstruction of the phylogenetic relationship among siluriform fishes. The significance of the extra C-terminal tail for AR function remains elusive.

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Section: Discussioncontrasting

confidence: 86%

Isolation, sequence analysis, and characterization of androgen receptor in Southern catfish, Silurus meridionalis

Huang

Sun

et al. 2010

Fish Physiol Biochem

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“…Similarly in the Nile tilapia most of these steroidogenic enzyme genes were also expressed in undifferentiated XX gonads (around 5-10 dph) and later gradually increased in both sexes [Ijiri et al, 2008]. Further, earlier reports on the manipulation/skewing of sex in catfish hatchlings during early development (before sex differentiation) and complete sex reversal of XY tilapia fry by following ethynylestradiol treatment prove that estrogen is produced in female gonads during the critical period of ovarian differentiation and plays a crucial role in female development [Nagahama, 2005;Raghuveer et al, 2005]. 11-KT is the most potent androgen in teleosts which is synthesized from testosterone [Nakamura et al, 1998].…”

Section: Discussionmentioning

confidence: 97%

Dimorphic Expression of Various Transcription Factor and Steroidogenic Enzyme Genes during Gonadal Ontogeny in the Air-Breathing Catfish, <i>Clarias gariepinus</i>

Kavarthapu

Senthilkumaran

Sudhakumari

et al. 2011

Sex Dev

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In the present study the expression of 13 genes known to be involved in sex differentiation and steroidogenesis in catfish was analyzed during gonadal ontogeny by quantitative real-time RT-PCR. Dmrt1 and sox9a showed exclusive expression in male gonads while ovarian aromatase (cyp19a1) and foxl2 were abundant in differentiating female gonads. Most of the genes related to steroidogenesis were expressed only after gonadal differentiation. However, genes coding for 3β-hydroxysteroid dehydrogenase (3β-hsd), 17α-hydroxylase/C17–20 lyase type 1 (cyp17) and steroidogenic acute regulatory protein (star) were barely detectable during gonadal differentiation. Ovarian aromatase, cyp19a1, which is responsible for estradiol-17β biosynthesis in females, was expressed very early in the undifferentiated gonads of catfish, around 30–40 days post hatch (dph). The steroidogenic enzyme, 11β-hydroxylase (cyp11b1) required for the production of 11-ketotestosterone (11-KT) was expressed only after differentiation of testis. These results suggest that estradiol-17β has a critical role in ovarian differentiation, while the role of 11-KT in testicular differentiation is doubtful. In conclusion, dimorphic expression of dmrt1 and sox9a in gonads during early development is required for testicular differentiation, and sex-specific expression of cyp19a1 and foxl2 in females plays a critical role in ovarian development. Our study reveals that the critical period of gonadal differentiation in catfish starts around 30–40 dph when sex-specific genes showed differential expression.

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“…In the channel catfish, neither aromatizable nor non-aromatizable androgen could induce female-to-male sex reversal (Davis et al 1990). However, androgen can induce sex reversal in some species, such as the African catfish (Clarias gariepinus; Raghuveer et al 2006), the Nile tilapia (Bhandari et al 2006), and rainbow trout ), so why not in others, such as the channel catfish and the Southern catfish investigated here? It is uncertain whether this is due to species specificity or different treatments.…”

Section: Sex Reversal By the Blockage Of Estrogen Production And Funcmentioning

confidence: 89%

Studies on feminization, sex determination, and differentiation of the Southern catfish, Silurus meridionalis—a review

Liu

Zhang

Wang

2008

Fish Physiol Biochem

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The sex ratio of the feral Southern catfish was reported to be about 1:1, while the fish obtained by artificial fertilization were always female. Hence, we examined the possible influence of the micro-environment during artificial insemination (pH of the ovarian fluid and concentration of the semen) and early development (feed, hatching temperature, and water) on the sex ratio of Southern catfish fry. In order to examine the possibility of the occurrence of gynogenesis during artificial propagation, cytological observations on the insemination processes and the artificial induction of gynogenesis were also performed. However, no male fish were obtained even in these experiments, excluding the possibilities of these micro-environmental changes on catfish sex ratio and the occurrence of gynogenesis during artificial propagation. Female-to-male sex reversal was achieved by treatment with fadrozole (an aromatase inhibitor) and tamoxifen (an estrogen receptor antagonist). Histological analyses on the gonadal development of both female and induced male fish were subsequently performed. Moreover, several genes involved in sex differentiation, such as dmrt1, foxl2, and cyp19, and three subunits of gonadotropin (gth), i.e., gthalpha, lhbeta, and fshbeta, were isolated. Their expression patterns were studied under normal gonadal development and sex reversal conditions. The results revealed that dmrt1, foxl2, and cyp19a were closely related to catfish sex differentiation, and the gth subunits were possibly related to ovarian differentiation and oocyte development. Taken together, we hypothesized that estrogen was highly responsible for the ovarian differentiation and feminization of catfish fry under artificial propagation, although the mechanism involved remains elusive.

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Effect of methyl testosterone- and ethynyl estradiol-induced sex differentiation on catfish, Clarias gariepinus: expression profiles of DMRT1, Cytochrome P450aromatases and 3 β-hydroxysteroid dehydrogenase

Cited by 21 publications

References 6 publications

Isolation, sequence analysis, and characterization of androgen receptor in Southern catfish, Silurus meridionalis

Isolation, sequence analysis, and characterization of androgen receptor in Southern catfish, Silurus meridionalis

Dimorphic Expression of Various Transcription Factor and Steroidogenic Enzyme Genes during Gonadal Ontogeny in the Air-Breathing Catfish, <i>Clarias gariepinus</i>

Studies on feminization, sex determination, and differentiation of the Southern catfish, Silurus meridionalis—a review

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