Expression of P45017αHydroxylase and P450 Aromatase Genes in the Chicken Gonad before and after Sexual Differentiation

Yoshida, Kumiko; Shimada, Kiyoshi; Sakai, Noboru

doi:10.1006/gcen.1996.0064

Cited by 96 publications

(53 citation statements)

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“…At the onset of morphological asymmetry of the female gonads (day 7), both P450 arom and ERa were expressed at significantly higher levels in the left than in the right gonad. Similar asymmetry in P450 arom and ERa expression has also been described for developing chicken gonads (Yoshida et al 1996, Nakabayashi et al 1998, Villalpando et al 2000, Sakimura et al 2002. Estrogen-binding sites and ERa protein have been located to the germinal epithelium of the left gonad and to the medulla of both gonads in early chicken embryos of both sexes (Gasc 1980, Guioli & Lovell-Badge 2007, Ishimaru et al 2008.…”

Section: Era-mediated Effects In Quail Embryossupporting

confidence: 59%

Selective estrogen receptor α activation disrupts sex organ differentiation and induces expression of vitellogenin II and very low-density apolipoprotein II in Japanese quail embryos

Mattsson

Olsson²,

Brunström

2008

Reproduction

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The Japanese quail (Coturnix japonica) is a widely used model species for studying the roles of steroid hormones in avian sex differentiation. The aim of the present study was to elucidate the significance of estrogen receptors a and b (ERa and ERb) in normal sex differentiation of the reproductive organs in the Japanese quail and in xenoestrogen-induced disruption of reproductive organ differentiation. Real-time PCR indicated that ERa (ESR1) mRNA is expressed in both right and left gonads and Müllerian ducts (MDs) in both sexes during early morphological differentiation. ERb (ESR2) transcripts were also detected in gonads and MDs, but at very low levels. Both receptor subtypes were expressed in the liver and may therefore mediate the expression of estrogen-regulated egg-yolk proteins. Aromatase mRNA was expressed at much higher levels in female than male gonads as early as embryonic day 5, indicating early sex differences in estrogen synthesis. Treatment with the ERa-selective agonist propyl pyrazole triol showed that frequently reported xenoestrogen effects, such as ovotestis formation, abnormal MD development, and hepatic expression of egg-yolk proteins, were induced by selective activation of ERa. Taken together, our results suggest that activation of ERa is crucial for estrogen-dependent sex differentiation of the reproductive organs and that ERa mediates xenoestrogen-induced toxicity during reproductive development in birds.

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Section: Era-mediated Effects In Quail Embryossupporting

confidence: 59%

Selective estrogen receptor α activation disrupts sex organ differentiation and induces expression of vitellogenin II and very low-density apolipoprotein II in Japanese quail embryos

Mattsson

Olsson²,

Brunström

2008

Reproduction

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“…3). Recently, Yoshida et al (1996) compared expression of aromatase and P-450c17 genes in embryonic gonads of chicken using an experimental approach similar to that in the present study, and showed that the aromatase gene was expressed only in female gonads. However, our present study is the first to compare expression of all the five genes required for the synthesis of estradiol-17 during gonadal development in chicken embryos.…”

Section: Differential Gene Expression In Developing Chicken Gonads · mentioning

confidence: 75%

Differential expression of genes for aromatase and estrogen receptor during the gonadal development in chicken embryos

Nakabayashi¹,

Kikuchi²,

Kikuchi³

et al. 1998

Journal of Molecular Endocrinology

129

107

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In birds, differentiation of embryonic gonads is not as strictly determined by the genetic sex as it is in mammals, and can be influenced by early manipulation with a sex steroid hormone. Thus administration of an aromatase inhibitor induces testis development in the genetic female, and administration of estrogen induces a left ovotestis in the genetic male embryo. Another feature of avian gonadogenesis is that only the left ovary develops in most species. Molecular mechanisms underlying these features at the level of gene expression have not been elucidated. In this paper, we present evidence that a gene for aromatase cytochrome P-450, an enzyme required for the last step in the synthesis of estradiol-17 , is expressed in medullae of the left and right gonads of a female chicken embryo, but not in those of a male chicken embryo, and that an estrogen receptor gene is expressed only in epithelium (and cortex later, in the female) of the left, not the right, gonad of both sexes, but the expression in the male left gonad is temporary and restricted to an early stage of development. Differential expression of these two genes serves well to explain the above features of gonadal development in birds. Furthermore, in ovo administration of estradiol-17 from the 5th to the 14th day of incubation does not cause expression of the estrogen receptor gene in the right gonad of chicken embryos of either sex, suggesting that the absence of expression of the estrogen receptor gene in the right gonad is not the result of down-regulation, but may be regarded as an important cause of the unilateral ovarian development.

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“…Less is known about the control of ovarian differentiation. It has been established that morphological differentiation of the ovary in chicken occurs on stage 30 (embryonic day [E]6, 5-7) according to Hamburger and Hamilton's classification (Hamburger and Hamilton, 1951) and coincides with activation of the expression of P450-aromatase, which converts androgens to estrogens (Yoshida et al, 1996;Smith et al, 1997). Estrogens seem to play a crucial role in cortex formation and germ cell and supporting cell proliferation.…”

Section: Introductionmentioning

confidence: 99%

Isolation of chicken homolog of the FOXL2 gene and comparison of its expression patterns with those of aromatase during ovarian development

Govoroun

Pannetier

Pailhoux

et al. 2004

Developmental Dynamics

192

119

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Mutations in the forkhead transcription factor gene FOXL2 are involved in ovarian failure, which occurs in human BPES syndrome. This syndrome presents a sexually dimorphic expression, specific to the ovary in several vertebrates. We cloned the open reading frame of chicken FOXL2 (cFoxL2) and studied cFoxL2 expression in developing gonads and during adulthood to examine the role of FOXL2 in ovarian differentiation and function in birds. The spatial and temporal dynamics of cFoxL2 and aromatase expression were analyzed in parallel by using real-time quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry in attempt to investigate the possible role of cFoxL2 in the regulation of aromatase. The expression patterns of cFoxL2 and aromatase transcripts were highly correlated during the sex-differentiation period (4.7-12.7 days of incubation). Aromatase and cFoxL2 proteins were colocalized in the medullar part of female gonads on embryonic day 14. Fourteen days after hatching, cFoxL2 protein was mainly detected in granulosa cells of developing follicles. In adult ovary follicular envelopes, apart from granulosa cells, cFoxL2 transcript and protein were detected at lower levels in theca cells where aromatase was present. A high level of cFoxL2 transcription was also observed in maturing and ovulated oocytes. Our results confirm that FoxL2 is an early regulator of ovarian development in birds and may be involved in aromatase transcription regulation. Developmental Dynamics 231:859 -870, 2004.

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Expression of P45017αHydroxylase and P450 Aromatase Genes in the Chicken Gonad before and after Sexual Differentiation

Cited by 96 publications

References 0 publications

Selective estrogen receptor α activation disrupts sex organ differentiation and induces expression of vitellogenin II and very low-density apolipoprotein II in Japanese quail embryos

Selective estrogen receptor α activation disrupts sex organ differentiation and induces expression of vitellogenin II and very low-density apolipoprotein II in Japanese quail embryos

Differential expression of genes for aromatase and estrogen receptor during the gonadal development in chicken embryos

Isolation of chicken homolog of the FOXL2 gene and comparison of its expression patterns with those of aromatase during ovarian development

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