Structure and Expression of a New Complementary DNA Encoding the almost Exclusive 3β-Hydroxysteroid Dehydrogenase/Δ<sup>5</sup>-Δ<sup>4</sup>-lsomerase in Human Adrenals and Gonads

Rhéaume, Éric; Lachance, Yves; Zhao, Huifen; Breton, Nathalie; Dumont, M.; Launoit, Yvan de; Trudel, Claude; Luu‐The, Van; Simard, Jacques; Labrie, Fernand

doi:10.1210/mend-5-8-1147

Cited by 339 publications

(175 citation statements)

References 57 publications

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“…To determine whether intracellular conversion of a steroid to AD can cause maturation similarly to exogenous addition of AD, we asked whether oocytes could be engineered to respond to a poor promoter of maturation, DHEA, by acquiring the capacity to convert DHEA to AD. Oocytes were injected with either buffer or cRNA encoding human 3␤-hydroxysteroid dehydrogenase͞isomerase type II (HSDII), which converts DHEA to AD (16). As expected, mock-injected oocytes matured in response to AD; however, they were virtually unresponsive to DHEA at concentrations up to 1 M (Fig.…”

Section: Intracellular Metabolism Of Steroids Can Regulate the Oocytementioning

confidence: 63%

Evidence that androgens are the primary steroids produced by Xenopus laevis ovaries and may signal through the classical androgen receptor to promote oocyte maturation

Lutz

Cole

Gupta

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

156

142

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Steroid-induced maturation of Xenopus oocytes has long served as a model for studying meiosis. Progesterone has been considered the relevant steroid controlling maturation, perhaps through interactions with classical progesterone receptors. In this study, we provide evidence that androgens, rather than progesterone, are the physiologic mediators of Xenopus oocyte maturation. Androgens were equal or more potent activators of maturation in vitro relative to progesterone and were significantly more abundant in the serum and ovaries of ␤-human chorionic growth hormone-stimulated frogs. Androgen action appeared to be mediated by classical androgen receptors (ARs) expressed in oocytes, as androgen-induced maturation and signaling was specifically attenuated by AR antagonists. Interestingly, we found that progesterone was rapidly converted to the androgen androstenedione in isolated oocytes by the enzyme CYP17, suggesting that androgens may be promoting maturation even under conditions typical for ''progesterone-mediated'' maturation assays. Androgens are thought to play an important role in ovarian development as well as pathology, and signaling through the AR may prove to be a major regulatory mechanism mediating these processes.T he phenomenon of progesterone-induced maturation of Xenopus oocytes has served as an in vitro experimental model for studying meiosis and cell cycle regulation for over 30 years (1-3), with recent work implicating the classical nuclear͞cytoplasmic progesterone receptor (PR) as the mediator of these processes (4, 5). Although progesterone is a potent promoter of Xenopus oocyte maturation in vitro, little is known about its role in mediating maturation in vivo. In other animals, progesterone does not appear to be the primary physiologic mediator of oocyte maturation. For example, oocyte maturation in fish is mediated by the progesterone metabolite 17␣, 20␤-dihydroxyprogesterone (6). In mice, ovaries from females lacking the PR gene still contain well-developed follicles with mature oocytes (7), suggesting that progesterone and its receptor are not necessary for oocyte maturation and that other factors are therefore important. Finally, mifepristone (RU486), a potent inhibitor of both mammalian and Xenopus PR-mediated transcription, does not block progesterone-mediated maturation (5), implying that, even in vitro, signaling via the PR may not be the only mechanism behind progesterone-induced maturation.In an effort to clarify the physiologic importance of progesterone in Xenopus oocyte maturation, we measured the serum and ovarian steroid content of female frogs injected with ␤-human chronic growth hormone (␤-hCG). We show that progesterone is barely detectable in the serum and ovaries of these animals but that androgen concentrations are Ͼ10 times higher than that of progesterone. Further, we demonstrate that oocytes are equally or more sensitive to signaling by androstenedione (AD) and testosterone than progesterone. We identify classical Xenopus androgen receptors (ARs) in oocytes and show t...

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Section: Intracellular Metabolism Of Steroids Can Regulate the Oocytementioning

confidence: 63%

Evidence that androgens are the primary steroids produced by Xenopus laevis ovaries and may signal through the classical androgen receptor to promote oocyte maturation

Lutz

Cole

Gupta

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

156

142

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“…An overall homology of 48% was found between the amino acid sequence of rainbow trout and that of human 3fl-HSD type I, type II [9,12,13], macaque 3fl-HSD [14] and bovine 3fl-HSD [15]. The mouse 3fl-HSD type I and type III [16] amino acid sequence shared 46% homology with that of rainbow trout.…”

Section: Comparison Of the Deduced Amino Acid Sequence Of Trout 3~-hsmentioning

confidence: 99%

“…3). The data indicate the presence of a single gene encoding 3fl-HSD in the rainbow trout, differing from the multiple related 3~-HSD isoenzymes in human [9,12,13,[25][26][27], rat [8,17,18], and mouse [16].…”

Section: Northern and Southern Blot Hybridization Analysis Ofmentioning

confidence: 99%

Ovarian 3,β‐hydroxysteroid dehydrogenase/Δ^5‐4‐isomerase of rainbow trout: Its cDNA cloning and properties of the enzyme expressed in a mammalian cell

et al. 1994

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A cDNA clone encoding 3j%hydroxysteroid dehydrogenaseld S4-isomerase (3j%HSD) was isolated from a cDNA library of rainbow trout ovarian thecal cells. Southern hyb~dization analysis of trout genomic DNA with the cDNA suggested the presence of a single gene encoding 3&HSD in the rainboa trout showing a total genomic size of less than 4 kilobases (kb). The cDNA hybridized to a single species of mRNA isolated from rainbow trout ovaries; the 1.4 kb transcripts were most abundant m trout ovaries during the later stages of oogenesis. The trout 3/?-HSD expressed in non-~teroidogenic monkey kidney tumor (COS-I) cells showed a unique enzymatic 3&HSD activity. ~hydr~iandrosterone was a more favoral substrate of the trout 3&HSll than 17a-hydroxypregnenolonc. Interestingly. the trout 3&HSD expressed in COS-I cells exhibited minimal ability to convert pregnenolone to progesterone.

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“…The human type 1 (placenta, mammary gland, and prostate) and type 2 (adrenals, ovary, and testis) isoforms of 3␤-hydroxysteroid dehydrogenase (EC 1.1.1.145)/steroid ⌬ 5 -⌬ 4 -isomerase (EC 5.3.3.1) (3␤-HSD1 1 and 3␤-HSD2) are encoded by two distinct genes that are expressed in a tissue-specific pattern (1). As shown in Fig.…”

mentioning

confidence: 99%

Identification of Key Amino Acids Responsible for the Substantially Higher Affinities of Human Type 1 3β-Hydroxysteroid Dehydrogenase/Isomerase (3β-HSD1) for Substrates, Coenzymes, and Inhibitors Relative to Human 3β-HSD2

Thomas

Boswell

Scaccia

et al. 2005

Journal of Biological Chemistry

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The human type 1 (placenta, breast tumors, and prostate tumors) and type 2 (adrenals and gonads) isoforms of 3␤-hydroxysteroid dehydrogenase/isomerase (3␤-HSD1 and 3␤-HSD2) are encoded by two distinct genes that are expressed in a tissue-specific pattern. Our recent studies have shown that His 156 contributes to the 14-fold higher affinity that 3␤-HSD1 exhibits for substrate and inhibitor steroids compared with human 3␤-HSD2 containing Tyr 156 in the otherwise identical catalytic domain. Our structural model of human 3␤-HSD localizes His 156 or Tyr 156 in the subunit interface of the enzyme homodimer. The model predicts that Gln 105 on one enzyme subunit has a higher probability of interacting with His 156 on the other subunit in 3␤-HSD1 than with Tyr 156 in 3␤-HSD2. The Q105M mutant of 3␤-HSD1 (Q105M1) shifts the Michaelis-Menten constant (K m ) for 3␤-HSD substrate and inhibition constants (K i ) for epostane and trilostane to the much lower affinity profiles measured for wild-type 3␤-HSD2 and H156Y1. However, the Q105M2 mutant retains substrate and inhibitor kinetic profiles similar to those of 3␤-HSD2. Our model also predicts that Gln 240 in 3␤-HSD1 and Arg 240 in 3␤-HSD2 may be responsible for the 3-fold higher affinity of the type 1 isomerase activity for substrate steroid and cofactors. The Q240R1 mutation increases the isomerase substrate K m by 2.2-fold to a value similar to that of 3␤-HSD2 isomerase and abolishes the allosteric activation of isomerase by NADH. The R240Q2 mutation converts the isomerase substrate, cofactor, and inhibitor kinetic profiles to the 4 -14-fold higher affinity profiles of 3␤-HSD1. Thus, key structural reasons for the substantially higher affinities of 3␤-HSD1 for substrates, coenzymes, and inhibitors have been identified. These structure and function relationships can be used in future docking studies to design better inhibitors of the 3␤-HSD1 that may be useful in the treatment of hormone-sensitive cancers and preterm labor.The human type 1 (placenta, mammary gland, and prostate) and type 2 (adrenals, ovary, and testis) isoforms of 3␤-hydroxysteroid dehydrogenase (EC 1.1.1.145)/steroid ⌬ 5 -⌬ 4 -isomerase (EC 5.3.3.1) (3␤-HSD1 1 and 3␤-HSD2) are encoded by two distinct genes that are expressed in a tissue-specific pattern (1). As shown in Fig. 1, human 3␤-HSD1 catalyzes the conversion of 3␤-hydroxy-5-ene-steroids (dehydroepiandrosterone (DHEA) and pregnenolone) to 3-oxo-4-ene-steroids (androstenedione and progesterone), and human 3␤-HSD2 converts 17␣-hydroxypregnenolone and pregnenolone to ultimately produce cortisol and aldosterone in the human adrenal, respectively (2). 17␣-Hydroxylase/17,20 lyase (CYP17) in the human adrenal gland converts pregnenolone to DHEA, which is the major circulating steroid in humans as DHEA sulfate (2). In placenta, androstenedione is converted by aromatase and 17␤-hydroxysteroid dehydrogenase (17␤-HSD) to estradiol, which participates in the cascade of events that initiates labor in humans (2, 3). Placental 3␤-HSD1 also converts pregnenolone to...

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Structure and Expression of a New Complementary DNA Encoding the almost Exclusive 3β-Hydroxysteroid Dehydrogenase/Δ⁵-Δ⁴-lsomerase in Human Adrenals and Gonads

Cited by 339 publications

References 57 publications

Evidence that androgens are the primary steroids produced by Xenopus laevis ovaries and may signal through the classical androgen receptor to promote oocyte maturation

Evidence that androgens are the primary steroids produced by Xenopus laevis ovaries and may signal through the classical androgen receptor to promote oocyte maturation

Ovarian 3,β‐hydroxysteroid dehydrogenase/Δ^5‐4‐isomerase of rainbow trout: Its cDNA cloning and properties of the enzyme expressed in a mammalian cell

Identification of Key Amino Acids Responsible for the Substantially Higher Affinities of Human Type 1 3β-Hydroxysteroid Dehydrogenase/Isomerase (3β-HSD1) for Substrates, Coenzymes, and Inhibitors Relative to Human 3β-HSD2

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Structure and Expression of a New Complementary DNA Encoding the almost Exclusive 3β-Hydroxysteroid Dehydrogenase/Δ5-Δ4-lsomerase in Human Adrenals and Gonads

Cited by 339 publications

References 57 publications

Evidence that androgens are the primary steroids produced by Xenopus laevis ovaries and may signal through the classical androgen receptor to promote oocyte maturation

Evidence that androgens are the primary steroids produced by Xenopus laevis ovaries and may signal through the classical androgen receptor to promote oocyte maturation

Ovarian 3,β‐hydroxysteroid dehydrogenase/Δ5‐4‐isomerase of rainbow trout: Its cDNA cloning and properties of the enzyme expressed in a mammalian cell

Identification of Key Amino Acids Responsible for the Substantially Higher Affinities of Human Type 1 3β-Hydroxysteroid Dehydrogenase/Isomerase (3β-HSD1) for Substrates, Coenzymes, and Inhibitors Relative to Human 3β-HSD2

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Structure and Expression of a New Complementary DNA Encoding the almost Exclusive 3β-Hydroxysteroid Dehydrogenase/Δ⁵-Δ⁴-lsomerase in Human Adrenals and Gonads

Ovarian 3,β‐hydroxysteroid dehydrogenase/Δ^5‐4‐isomerase of rainbow trout: Its cDNA cloning and properties of the enzyme expressed in a mammalian cell