Sterol 14-alpha-demethylase encoded by the CYP51 gene is a member of the cytochrome P450 gene superfamily
involved in sterol biosynthesis in fungi, plants, and animals. CYP51 is an evolutionarily conserved, housekeeping gene of the cytochrome P450
superfamily which is involved in cholesterol biosynthesis in animals.
NCBI Summary:
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This endoplasmic reticulum protein participates in the synthesis of cholesterol by catalyzing the removal of the 14alpha-methyl group from lanosterol. Homologous genes are found in all three eukaryotic phyla, fungi, plants, and animals, suggesting that this is one of the oldest cytochrome P450 genes. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Mar 2009]
General function
Metabolism, Enzyme, Transferase
Comment
A cDNA encoding human P450(14DM) was isolated from a liver cDNA library using a
partial rat lanosterol 14 alpha-demethylase cDNA probe. Stromstedt M, et al The deduced amino acid sequence is 93% and
38--42% identical to rat and fungal P450(14DM), respectively. Expression of the human CYP51 cDNA
in Escherichia coli showed that the cDNA encodes an enzyme having lanosterol 14 alpha-demethylase
activity.
Cellular localization
Cytoplasmic
Comment
Ovarian function
Follicle endowment, Steroid metabolism, Oogenesis, Oocyte maturation, Early embryo development
Comment
Retinoic acid-induced CYP51 nuclear translocation promotes meiosis prophase I process and is correlated to the expression of REC8 and STAG3 in mice. Mu X et al. (2018) Lanosterol 14 α-demethylase (CYP51) plays a crucial role in cholesterol biosynthesis. In gamete development, CYP51 is involved in initiating meiosis resumption in oocytes through its product, meiosis activating sterol (MAS). In this study, CYP51 was observed to localize within the nucleus of germ cells undergoing meiotic prophase I. Following the addition of retinoic acid (RA) to induce meiosis or the RA receptor pan-antagonist AGN193109 to block meiosis in fetal ovaries, the translocation of CYP51 into the nucleus of oocytes was advanced or delayed, respectively. In addition, treatment with Cyp51-siRNA or RS21745, a specific CYP51 inhibitor, significantly delayed the meiotic progression of oocytes in the ovary, with most oocytes arresting at the zygotene stage, and likewise, significantly reduced perinatal primordial follicle formation. Furthermore, inhibition of CYP51 is correlated to significantly decreased expression of REC8 and STAG3, both of which are meiosis-specific cohesin subunits. To sum up, RA-induced CYP51 nuclear translocation is critical for oocytes meiotic progression, and consequently folliculogenesis, which might act through impacting the expression of meiosis-specific cohesins REC8 and STAG3.//////////////////
CYP51A1 Induced by Growth Differentiation Factor 9 and Follicle-Stimulating Hormone in Granulosa Cells Is a Possible Predictor for Unfertilization. Nakamura T 2014 et al.
Growth differentiation factor 9 (GDF9), an oocyte-secreted factor, whose receptors exist in granulosa cells, is involved in follicle progression. Therefore, GDF9 is considered to potentially mediate signals necessary for follicular growth. However, the effect of GDF9 on human granulosa cells is not fully understood. Human immortalized nonluteinized granulosa cell line (HGrC1) which we have previously reported was stimulated with GDF9 and/or follicle-stimulating hormone (FSH). Granulosa cells obtained from in vitro fertilization (IVF) patients were also evaluated with quantitative reverse transcription polymerase chain reaction (RT-PCR). Real-time RT-PCR showed that GDF9 increased messenger RNA (mRNA) levels of enzymes required for cholesterol biosynthesis, such as 3-hydroxy-3-methylglutanyl-CoA synthase 1 (HMGCS1), farnesyl-diphosphate farnesyltransferase 1, squalene epoxidase, lanosterol synthase, and cytochrome P450, family 51, subfamily A, polypeptide 1 (CYP51A1). A greater increase in mRNA levels of HMGCS1 and CYP51A1 was observed by combined treatment with GDF9 and FSH. Clinical samples showed a significant increase in CYP51A1 mRNA in the group of granulosa cells connected with unfertilized oocytes. Our results suggest that GDF9, possibly with FSH, may play significant roles in the regulation of cholesterol biosynthesis and the expression of CYP51A1 which might be a predictor for unfertilization.
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Reducing CYP51 inhibits FSH-induced resumption of mouse oocyte meiosis in vitro. Wang C et al. Meiosis activating sterol, produced directly by lanosterol 14-a-demethylase (CYP51) during cholesterol biosynthesis has been shown to promote the initiation of oocyte meiosis. However, the physiological significance of CYP51 action on oocyte meiosis in response to gonadotrophins' induction remained to be further explored. Herein, we analyzed the role of CYP51 in gonadotrophin-induced in vitro oocyte maturation via RNA interference. We showed that although both LH and FSH significantly induced meiotic resumption in follicle-enclosed oocytes (FEOs), the effect of LH on oocyte meiosis resumption in FEOs was weaker than FSH. Moreover, both FSH and LH were able to up-regulate CYP51 expression in cultured follicular granulosa cells when examined at 8 or 12 hrs post-treatments, respectively. Interestingly, while knockdown of CYP51 expression via siRNAs moderately blocked(23% reduction at 24 h) FSH-induced oocyte maturation (43% germinal vesicle break down (GVBD) rate in RNAi vs 66% in control, p<0.05) in FEOs, similar treatments showed no apparent effects on LH-induced FEO meiotic maturation (58% GVBD rate in RNAi vs 63% in control, p>0.05). Moreover, the results in cumulus-enclosed oocytes (CEOs) model showed that approximately 30% of FSH induced CEOs' meiotic resumption were blocked upon CYP51 knockdown by siRNAs. These findings suggested that FSH, partially at least, employs CYP51, therefore MAS pathway to initiate oocyte meiosis.
Lanosterol metabolic product(s) is involved in primordial folliculogenesis and establishment of primordial folliclepool in mouse fetal ovary. Zhang H et al. The primordial follicles present in neonatal ovary represent the fecundity of a female throughout her reproductive life. Germ cell meiosis and apoptosis are two important events during primordial folliculogenesis. In this study, through focusing on the cytochrome P450 lanosterol 14 alphademethylase (CYP51) and its lanosterol metabolic product(s), we explored the possible regulatory mechanism of the initiation of germ cell meiosis and primordial follicle formation. The expression of CYP51 could be detected in both oocytes and granulosa cells during primordial folliculogenesis by immunochemistry. RS21745, which leads to the reduction of lanosterol metabolic product(s) level, inhibited the primordial follicle formation in a dose-dependent manner, and thus postpone the establishment of the primordial follicle pool when the mouse fetal ovaries were cultured in serum-free medium. In contrast, the number of primordial follicle increased significantly with the accumulation of the lanosterol metabolic products caused by 0.025, 0.0625, and 0.125 microM AY9944-A-7 supplements. AY9944-A-7 also up-regulated the expression of meiotic diplotene stage marker gene msy2 and primordial follicle formation regulatory gene fig-alpha. Furthermore, AY9944-A-7 decreased the expression of apoptosis gene bax and significantly prevented oocyte apoptosis from 15.37 +/- 1.97% to 3.68 +/- 0.27% (P < 0.01) in neonatal ovary in vitro. In conclusion, our results indicate that lanosterol metabolic product(s) is involved in the primordial folliculogenesis by regulating the oocyte meiosis and apoptosis. Mol. Reprod. Dev. (c) 2008 Wiley-Liss, Inc.
Rozman D reviewed the role of CYP51 in gonads. The two intermediates of cholesterol biosynthetis pathway, sterol FF-MAS, produced by CYP51 and the following sterol T-MAS, accumulate: in follicular fluid and in
testis. CYP51 is expressed in all tissues in mammals with the highest level in the testis. Promoters of the human and fat CYP51 genes contain SRE and CRE
elements which indicate two main regulatory routes - the sterol-dependent
regulation and the cAMP-dependent regulation. While feedback regulation by
sterols is characteristic for all genes involved in cholesterol biosynthesis
and homeostasis, the cAMP-dependent regulation is unique, indicating that
CYP51 may play tissue-specific roles distinct from cholesterol biosynthesis.
Stromstedt M, et al reported the ubiquitously expressed human CYP51 encodes lanosterol 14
alpha-demethylase, a cytochrome P450 whose expression is regulated by oxysterols.
Sterol biosynthesis requires the removal of the 14 alpha-methyl group from lanosterol in animals and
fungi and from obtusifoliol in plants. This reaction is catalyzed by a microsomal cytochrome P450, the
sterol 14 alpha-demethylase (P450(14DM), which is the only P450 described so far to be expressed in
different phyla.
Northern blot analysis showed that CYP51 mRNA is ubiquitously expressed with highest levels
in testis, ovary, adrenal, prostate, liver, kidney, and lung.
Lanosterol 14alpha-demethylase expression in the mouse ovary and its participation in cumulus-enclosed oocyte spontaneous meiotic maturation in vitro. Wang C et al. The expression of lanosterol 14alpha-demethylase (LDM) in the mouse ovary after gonadotrophin administration was examined and the action of follicle fluid meiosis activating sterol (FF-MAS), derived from lanosterol by the action of LDM, on oocyte spontaneous maturation was also evaluated in cumulus cell enclosed oocytes (CEOs). Expression of LDM was primarily in oocytes in primordial and secondary follicles prior to administration of gonadotrophins, but obvious LDM expression was apparent in ovarian somatic cells 48h after administration of equine chorionic gonadotrophin (eCG), especially in luteal and cumulus cells 54h after eCG or 48h after eCG plus 6h after human chorionic gonadotrophin (hCG). The LDM expression in oocytes was only slightly elevated in larger growing follicles after eCG treatment. On the contrary, 48h after hCG treatment, the elevated expression of LDM was only detected in interstitial cells. Therefore, eCG may be the primary gonadotrophin for LDM expression, and furthermore for production of FF-MAS in mouse cumulus cells (which are indispensable for oocyte maturation in vivo). Conversely, inhibitors of LDM, either 40muM azalanstat or 50muM RS-21745, significantly inhibited oocyte germinal vesicle breakdown (GVB) after 4h of in vitro culture; GVB rates decreased to 14 or 20%, compared to 90% in spontaneous maturation, respectively. There was no significant increase in GVB in CEOs following specific inhibitor of sterol Delta14-reductase and Delta7-reductase, AY9944-A-7 (5-100muM), until marked oocytes degeneration appeared (50muM). The phenomena may be ascribed to slow, passive accumulation of FF-MAS by AY9944-A-7, which cannot be associated with fast spontaneous progression. Furthermore, in spontaneous-matured CEOs, LDM was expressed preferentially in cumulus cells instead of oocytes. Therefore, FF-MAS may have a positive role in the spontaneous maturation of CEOs. In conclusion, there was an eCG-dependent dual LDM expression pattern on both oocytes and somatic cells in growing follicles in vivo, which may increase LDM expression and FF-MAS production in cumulus cells for oocyte maturation. For the first time, the inhibitory effect of LDM inhibitors on spontaneous maturation, together with the strong LDM expression in spontaneous matured CEOs, indicated that FF-MAS produced by cumulus cells might participate in spontaneous maturation of mouse CEOs.
Expression regulated by
FSH, LH, GDF9, T3
Comment
Role of CYP51 in the regulation of T3 and FSH-induced steroidogenesis in female mice. Liu J et al. (2017) Cytochrome P450 lanosterol 14α-demethylase (CYP51) is a key enzyme in sterols and steroids biosynthesis that involved in folliculogenesis and oocyte maturation, which is regulated by follicle stimulating hormone (FSH), as a key reproductive hormone during follicular development. Thyroid hormone (TH) is also important for normal reproductive function. Although T3 enhances FSH-induced preantral follicle growth, whether and how TH combines with FSH to regulate CYP51 expression during preantral to early antral transition stage is unclear. The objective of this study was to determine the cellular and molecular mechanisms by which T3 and FSH regulate CYP51 expression and steroid biosynthesis during preantral follicle growth. Our results indicated that CYP51 expression was upregulated in granulosa cells by FSH, and this response was enhanced by T3. Moreover, knockdown CYP51 also decreased cell viability. Meanwhile, gene knockdown also blocked T3 and FSH-induced estradiol (E2) and progesterone (P4) synthesis. These changes were accompanied by up-regulation of phosphor-GATA-4 content. Results of siRNA analysis showed that knockdown of GATA-4 significantly declined CYP51 gene expression as well as E2/P4 levels. Furthermore, TRβ was necessary to the activation of PI3K/Akt, which was required to the regulation of CYP51 expression and activated GATA-4 was also involved these processes. Our data demonstrate that T3 and FSH co-treatment potentiates cellular development and steroid biosynthesis via CYP51 upregulation, which are mediated through the activation of the PI3K/Akt pathway. Meanwhile, activated GATA-4 is also involved in this regulatory system. These findings suggest that CYP51 is a novel mediator of T3 and FSH-induced follicular development.//////////////////
Yoshida Y et al reportd that sterol 14-demethylase P450 activity is expressed in rat gonads and contributes to the formation of mammalian meiosis-activating
sterol.
The P45014DM activity of immature ovaries was induced by pregnant mare's serum
gonadotropin.
Yamashita C, et al reported the gonadotropin-Dependent Expression of Sterol 14-Demethylase
P450 (CYP51) in Rat Ovaries and Its Contribution to the
Production of a Meiosis-Activating Steroid.
CREB up-regulated CYP51 expression involved in FSH-induced mouse oocyte maturation. Ning G et al. Cytochrome P450 lanosterol 14alpha-demethylase (CYP51) is a key enzyme in sterols and steroids biosynthesis that can induce meiotic resumption in mouse oocytes. The present study investigated the expression mechanism and function of CYP51 during FSH-induced mouse cumulus oocyte complexes (COCs) meiotic resumption. FSH increased cAMP-dependent protein kinase (PKA) RIIbeta level, induced cAMP response element binding protein (CREB) phosphorylation and CYP51 expression in cumulus cells prior to oocyte meiotic resumption. Moreover, CYP51 and epidermal growth factor (EGF)-like factor, amphiregulin (AR) expression were blocked by KG-501 (a drug interrupting the formation of CREB functional complex). KG-501 and RS21607 (a specific inhibitor of CYP51 activity) inhibited oocyte meiotic resumption, which can be partially rescued by progesterone. These two inhibitors also inhibited FSH-induced MAPK phosphorylation. EGF could rescue the suppression by KG-501 but not RS21607. Furthermore, type II PKA analog pairs, N(6)-cAMP plus 8-Br-cAMP, increased PKA RIIbeta level and mimiced the action of FSH, including CREB phosphorylation, AR and CYP51 expression, MAPK activation and oocyte maturation. All these data suggest that CYP51 plays a critical role in FSH-induced meiotic resumption of mouse oocytes. CYP51 and AR gene expression in cumulus cells are triggered by FSH via a type II PKA/CREB dependent signal pathway. Our study also implicates that CYP51 activity in cumulus cells participates in epidermal growth factor receptor (EGFR) signaling regulated oocyte meiotic resumption.
Ovarian localization
Oocyte, Cumulus, Granulosa, Theca, Luteal cells
Comment
Vaknin KM, et al 2001 studies the role of meiosis-activating sterols in rat oocyte maturation and changes in the expression of
lanosterol 14 alpha-demethylase during the preovulatory period.
Using
reverse transcriptase-polymerase chain reaction, Western blotting, and
immunocytochemistry, the ovarian expression of LDM mRNA and protein during the
preovulatory period was studies. The strongest staining by LDM antiserum was obtained in
primordial and primary oocytes, and the staining was reduced with oocyte
growth. In addition, strong LDM staining could be observed in some of the
granulosa cells, especially of the corona radiata localized in close proximity
to the oocyte.
Gonadotropin-regulated expressions of lanosterol 14alpha-demethylase, sterol Delta14-reductase and C-4 sterol methyl oxidase contribute to the accumulation of meiosis-activating sterol in rabbit gonads. Wang F et al. Meiosis-activating sterol (MAS), the intermediate of cholesterol biosynthesis, is an important lipophilic molecule mediating gonadotropins' action in inducing oocyte meiotic resumptions in various mammalian species. With respect to MAS's physiological relevance during oocyte maturation in the rabbit, early study has demonstrated that luteinizing hormone (LH), but not follicle stimulating hormone (FSH) can induce FF-MAS accumulation facilitating oocyte maturation in rabbits. However, the potential underlying mechanism for the MAS accumulation in the rabbit gonad remained unclear. We hypothesized that differential expression of MAS synthetic and metabolic enzymes would contribute to the timely MAS accumulation in the rabbit gonad. To address this issue, in the present investigation, we first cloned the cDNAs encoding there pre- and post-MAS enzymes, lanosterol 14alpha-demethylase (CYP51), sterol Delta14-reductase (14-SR) and C-4 sterol methyl oxidase (C4MO), respectively, using rapid amplification of cDNA ends (RACE) cloning, and then performed northern hybridization experiments to explore their expression profiles in the rabbit ovary, testis, and various other tissues. We observed that CYP51 expression was significantly upregulated only by LH/hCG in the antral follicle exhibiting its peak levels in preovulatory follicles; whereas both FSH and LH significantly downregulated 14-SR expression with the progression of antral follicular development. These findings provided here novel evidence that an inverse upregulation of CYP51 and downregulation of 14-SR expression under FSH/LH stimulation functions as the machinery for FF-MAS accumulation in preovulatory follicles prior to ovulation in the rabbit.
Follicle stages
Primordial, Primary, Secondary, Antral, Preovulatory, Corpus luteum
Comment
cDNA Cloning, Genomic Structure and Expression Analysis of the Bovine Lanosterol 14alpha-Demethylase (CYP51) in Gonads. Wang F et al. Meiosis activating sterol (MAS), the intermediate of cholesterol biosynthesis, is an important substance to stimulate oocytes maturation in FSH-induced signal transduction pathway. Lanosterol 14alpha-demethylase (CYP51) converts lanosterol to MAS. Although MAS is firstly isolated from bovine testis, the information about bovine CYP51 gene and its expression is little. In present studies, the cDNA cloning, genomic structure, chromosomal mapping, and expression patterns of bovine CYP51 were demonstrated. The cDNA coding bovine CYP51 contains a 1509 bp open reading frame and a 1119 bp 3' untranslated region. And the bovine CYP51 genen includes 10 exons and spans about 17 kb. Screening the cattle RH(5000) panel bovine CYP51 is mapped to chromosome 4 (0cR). The sequenced promoter region is TATA-less and contains several highly conserved regulatory elements, such as GC-box, cAMP-responsive elements (CRE), sterol regulatory element (SRE) which is important fragment for its transcription. No evidence of processed pseudogenes is found using long PCR and Southern blot. Northern blot analysis reveals that an approximately 2.7 kb mRNA is expressed in all the examined bovine tissues, while a 1.8 kb mRNA is found only in the mature bovine testis where the MAS is accumulated. Immunochemistry analysis shows that leydig cells express the highest level of the CYP51 protein in testis. Among different stages follicles it is localized primarily to the oocytes with the level varying slightly. Granulosa cells of primordial, primary and secondary follicles show background staining. While granulosa cells facing the antrum and cumulus granulosa cells of antral follicles show considerably heavier staining. The highest level is expressed in corpus lutea. These data indicate a stage- and cell type-specific expression of CYP51 protein in bovine oogenesis.