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Article: Steroidogenic factor-1 interacts with a gonadotrope-specific element within the first exon of the human gonadotropin-releasing hormone receptor gene to mediate gonadotrope-specific expression

TitleSteroidogenic factor-1 interacts with a gonadotrope-specific element within the first exon of the human gonadotropin-releasing hormone receptor gene to mediate gonadotrope-specific expression
Authors
Issue Date1999
PublisherThe Endocrine Society. The Journal's web site is located at http://endo.endojournals.org
Citation
Endocrinology, 1999, v. 140 n. 6, p. 2452-2462 How to Cite?
AbstractGnRH plays a pivotal role in regulating human reproductive functions. This hypothalamic peptide interacts with its receptor (GnRHR) on the pituitary gonadotropes to trigger the secretion of gonadotropins, which, in turn, regulates the release of sex steroids from the gonads. In light of the importance of GnRHR, the molecular mechanisms underlying the transcriptional regulation of the human GnRHR (hGnRHR) gene become a key issue in understanding human reproduction. In this report, the possible involvement of steriodogenic factor-1 (SF-1) as a key cell-specific regulator for hGnRHR gene expression was examined. By the transient luciferase reporter gene assays, the wild-type promoter, containing 2.3 kb of the hGnRHR gene 5′-flanking region relative to the ATG codon, was able to drive a 3.6 ± 0.2-fold (P < 0.05) increase in luciferase activity in the mouse αT3-1 gonadotropes. Subsequent deletion analysis indicated that the most proximal 173 bp within the first exon of the gene, although not a promoter itself, contains a critical regulatory element(s) essential for the basal expression of the hGnRHR gene. The functional roles of the putative gonadotrope-specific elements (GSE; consensus 5′-CTGA/TCCTTG-3′) residing at positions -5, -134, and -396 were studied by site-directed mutagenesis, and it was found that only the mutation at position -134 significantly reduced the promoter activity (80% reduction; P < 0.05). The attenuation effect of this GSE mutant was cell specific, as it was restricted to αT3-1 cells, but not to COS-7 and human ovarian adenocarcinoma (SKOV-3) cells. Competitive mobility shift assays using either αT3-1 nuclear extract or recombinant SF-1 protein clearly indicated that SF-1 is able to interact specifically with this GSE element positioned at -134. Using a SF-1 antibody that completely abrogated complex formation in the gel shift assays, the involvement of endogenous nuclear SF-1 was further evidenced. By competitive gel shift assays using oligoprimers with 2-bp scanning mutations, the sequences essential for the interaction with SF-1 were identified (5′-TTGA/TCCCTG-3′, underlined sequences were important). To study the in vivo function of SF-1, vector directing expression of sense or antisense SF-1 messenger RNA (mRNA) was cotransfected with the hGnRHR promoter-luciferase construct into αT3-1, SKOV-3, and COS-7 cells. Overexpression of the SF-1 mRNA was able to enhance promoter activities in all of the cells tested. On the contrary, expression of the antisense SF-1 mRNA reduced the hGnRHR promoter activity only in αT3-1 cells, not in COS-7 or SKOV-3 cells. In summary, the data reported here provide conclusive evidence that SF-1 interacts with the GSE motif at position -134 within the first exon of the hGnRHR gene to mediate its cell-specific expression.
Persistent Identifierhttp://hdl.handle.net/10722/84735
ISSN
2015 Impact Factor: 4.159
2015 SCImago Journal Rankings: 2.363
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorNgan, ESWen_HK
dc.contributor.authorCheng, PKWen_HK
dc.contributor.authorLeung, PCKen_HK
dc.contributor.authorChow, BKCen_HK
dc.date.accessioned2010-09-06T08:56:30Z-
dc.date.available2010-09-06T08:56:30Z-
dc.date.issued1999en_HK
dc.identifier.citationEndocrinology, 1999, v. 140 n. 6, p. 2452-2462en_HK
dc.identifier.issn0013-7227en_HK
dc.identifier.urihttp://hdl.handle.net/10722/84735-
dc.description.abstractGnRH plays a pivotal role in regulating human reproductive functions. This hypothalamic peptide interacts with its receptor (GnRHR) on the pituitary gonadotropes to trigger the secretion of gonadotropins, which, in turn, regulates the release of sex steroids from the gonads. In light of the importance of GnRHR, the molecular mechanisms underlying the transcriptional regulation of the human GnRHR (hGnRHR) gene become a key issue in understanding human reproduction. In this report, the possible involvement of steriodogenic factor-1 (SF-1) as a key cell-specific regulator for hGnRHR gene expression was examined. By the transient luciferase reporter gene assays, the wild-type promoter, containing 2.3 kb of the hGnRHR gene 5′-flanking region relative to the ATG codon, was able to drive a 3.6 ± 0.2-fold (P < 0.05) increase in luciferase activity in the mouse αT3-1 gonadotropes. Subsequent deletion analysis indicated that the most proximal 173 bp within the first exon of the gene, although not a promoter itself, contains a critical regulatory element(s) essential for the basal expression of the hGnRHR gene. The functional roles of the putative gonadotrope-specific elements (GSE; consensus 5′-CTGA/TCCTTG-3′) residing at positions -5, -134, and -396 were studied by site-directed mutagenesis, and it was found that only the mutation at position -134 significantly reduced the promoter activity (80% reduction; P < 0.05). The attenuation effect of this GSE mutant was cell specific, as it was restricted to αT3-1 cells, but not to COS-7 and human ovarian adenocarcinoma (SKOV-3) cells. Competitive mobility shift assays using either αT3-1 nuclear extract or recombinant SF-1 protein clearly indicated that SF-1 is able to interact specifically with this GSE element positioned at -134. Using a SF-1 antibody that completely abrogated complex formation in the gel shift assays, the involvement of endogenous nuclear SF-1 was further evidenced. By competitive gel shift assays using oligoprimers with 2-bp scanning mutations, the sequences essential for the interaction with SF-1 were identified (5′-TTGA/TCCCTG-3′, underlined sequences were important). To study the in vivo function of SF-1, vector directing expression of sense or antisense SF-1 messenger RNA (mRNA) was cotransfected with the hGnRHR promoter-luciferase construct into αT3-1, SKOV-3, and COS-7 cells. Overexpression of the SF-1 mRNA was able to enhance promoter activities in all of the cells tested. On the contrary, expression of the antisense SF-1 mRNA reduced the hGnRHR promoter activity only in αT3-1 cells, not in COS-7 or SKOV-3 cells. In summary, the data reported here provide conclusive evidence that SF-1 interacts with the GSE motif at position -134 within the first exon of the hGnRHR gene to mediate its cell-specific expression.en_HK
dc.languageengen_HK
dc.publisherThe Endocrine Society. The Journal's web site is located at http://endo.endojournals.orgen_HK
dc.relation.ispartofEndocrinologyen_HK
dc.rightsEndocrinology. Copyright © The Endocrine Society.en_HK
dc.titleSteroidogenic factor-1 interacts with a gonadotrope-specific element within the first exon of the human gonadotropin-releasing hormone receptor gene to mediate gonadotrope-specific expressionen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0013-7227&volume=140&spage=2452&epage=2462&date=1999&atitle=Steroidogenic+Factor-1+Interacts+with+a+Gonadotrope-Specific+Element+within+the+First+Exon+of+the+Human+Gonadotropin-Releasing+Hormone+Receptor+Gene+to+Mediate+Gonadotrope-Specific+Expressionen_HK
dc.identifier.emailNgan, ESW: engan@hku.hken_HK
dc.identifier.emailChow, BKC: bkcc@hku.hken_HK
dc.identifier.authorityNgan, ESW=rp00422en_HK
dc.identifier.authorityChow, BKC=rp00681en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1210/en.140.6.2452en_HK
dc.identifier.pmid10342829-
dc.identifier.scopuseid_2-s2.0-0033279280en_HK
dc.identifier.hkuros42303en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0033279280&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume140en_HK
dc.identifier.issue6en_HK
dc.identifier.spage2452en_HK
dc.identifier.epage2462en_HK
dc.identifier.isiWOS:000080419400003-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridNgan, ESW=22234827500en_HK
dc.identifier.scopusauthoridCheng, PKW=17338089300en_HK
dc.identifier.scopusauthoridLeung, PCK=12782513900en_HK
dc.identifier.scopusauthoridChow, BKC=7102826193en_HK

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