The cell-specific nuclear receptor steroidogenic factor 1 plays multiple roles in reproductive function

The cytochrome P450 steroid hydroxylases exhibit tissue-specific and developmentally regulated gene expression. Recent studies showed that the orphan nuclear receptor steroidogenic factor 1 (SF-1) plays a key role in their gene regulation. In mouse embryos, SF-1 expression began at the inception of adrenal and gonadal development, suggesting that SF-1 plays a key role in the steroidogenic cell differentiation. SF-1 was also expressed in the developing pituitary gland and diencephalon, which raised the possibility that it also has additional roles in endocrine development. To examine the role of SF-1 in intact mice, we disrupted the gene encoding SF-1 by homologous recombination in embryonic stem cells; this approach ultimately permitted us to generate SF-1 knockout mice in which the gene encoding SF-1 was inactivated. These studies revealed essential roles of SF-1 in endocrine development that included adrenal and gonadal development, expression of several markers of pituitary gonadotropes, and formation of the ventromedial hypothalamic (VMH) nucleus. These results indicate that SF-1 acts at multiple levels of the reproductive axis to maintain reproductive competence.

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Dax1 Up-Regulates Oct4 Expression in Mouse Embryonic Stem Cells via LRH-1 and SRA

Molecular Endocrinology ◽

10.1210/me.2010-0133 ◽

2010 ◽

Vol 24 (12) ◽

pp. 2281-2291 ◽

Cited By ~ 40

Author(s):

Victoria R. Kelly ◽

Bin Xu ◽

Rork Kuick ◽

Ronald J. Koenig ◽

Gary D. Hammer

Keyword(s):

Nuclear Receptor ◽

Transcriptional Activation ◽

Chromatin Immunoprecipitation ◽

Target Genes ◽

Embryonic Stem ◽

Steroid Receptor ◽

Orphan Nuclear Receptor ◽

Steroidogenic Factor 1 ◽

Oct4 Expression ◽

Mes Cells

Abstract Dax1 (Nr0b1) is an atypical orphan nuclear receptor that has recently been shown to play a role in mouse embryonic stem (mES) cell pluripotency. Here we describe a mechanism by which Dax1 maintains pluripotency. In steroidogenic cells, Dax1 protein interacts with the NR5A nuclear receptor steroidogenic factor 1 (Nr5a1) to inhibit transcription of target genes. In mES cells, liver receptor homolog 1 (LRH-1, Nr5a2), the other NR5A family member, is expressed, and LRH-1 has been shown to interact with Dax1. We demonstrate by coimmunoprecipitation that Dax1 is, indeed, able to form a complex with LRH-1 in mES cells. Because Dax1 was historically characterized as an inhibitor of steroidogenic factor 1-mediated transcriptional activation, we hypothesized that Dax1 would inhibit LRH-1 action in mES cells. Therefore, we examined the effect of Dax1 on the LRH-1-mediated activation of the critical ES cell factor Oct4 (Pou5f1). Chromatin immunoprecipitation localized Dax1 to the Oct4 promoter at the LRH-1 binding site, and luciferase assays together with Dax1 overexpression and knockdown experiments revealed that, rather than repress, Dax1 accentuated LRH-1-mediated activation of the Oct4 gene. Similar to our previously published studies that defined the RNA coactivator steroid receptor RNA activator as the critical mediator of Dax1 coactivation function, Dax1 augmentation of LRH-1-mediated Oct4 activation is dependent upon steroid receptor RNA activator. Finally, utilizing published chromatin immunoprecipitation data of whole-genome binding sites of LRH-1 and Dax1, we show that LRH-1 and Dax1 commonly colocalize at 288 genes (43% of LRH-1 target genes), many of which are involved in mES cell pluripotency. Thus, our results indicate that Dax1 plays an important role in the maintenance of pluripotency in mES cells through interaction with LRH-1 and transcriptional activation of Oct4 and other genes.

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Cloning and sequence analysis of the human gene encoding steroidogenic factor 1

Journal of Molecular Endocrinology ◽

10.1677/jme.0.0170139 ◽

1996 ◽

Vol 17 (2) ◽

pp. 139-147 ◽

Cited By ~ 66

Author(s):

M Wong ◽

M S Ramayya ◽

G P Chrousos ◽

P H Driggers ◽

K L Parker

Keyword(s):

Gonadal Development ◽

Hypothalamic Nucleus ◽

Endocrine Disorders ◽

Orphan Nuclear Receptor ◽

Gene Encoding ◽

Steroidogenic Factor 1 ◽

Ventromedial Hypothalamic Nucleus ◽

And Function ◽

Steroid Hydroxylases

ABSTRACT The orphan nuclear receptor steroidogenic factor 1 (SF-1) plays key roles in endocrine development and function. Initially identified as a positive regulator of the cytochrome P450 steroid hydroxylases, analyses of knockout mice deficient in SF-1 revealed that SF-1 is essential for adrenal and gonadal development, pituitary gonadotropin expression and formation of the ventromedial hypothalamic nucleus. Although more limited in scope, analyses of SF-1 in humans similarly have suggested that SF-1 is important for differentiated function in adrenocortical and gonadotrope adenomas. In the hope of extending our understanding of SF-1 function by identifying possible roles of SF-1 in clinical endocrine disorders, we isolated the FTZ-F1 gene encoding human SF-1 and mapped it to chromosome 9q33. In this report, we characterize the sequence and structural organization of the human cDNA and gene encoding SF-1, providing new insights into comparative aspects of SF-1 structure that will facilitate efforts to study the role of this transcription factor in human endocrine disorders.

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The orphan nuclear receptor NGFI-B regulates expression of the gene encoding steroid 21-hydroxylase

Molecular and Cellular Biology ◽

10.1128/mcb.13.2.861-868.1993 ◽

1993 ◽

Vol 13 (2) ◽

pp. 861-868

Author(s):

T E Wilson ◽

A R Mouw ◽

C A Weaver ◽

J Milbrandt ◽

K L Parker

Keyword(s):

Nuclear Receptor ◽

Transcriptional Activation ◽

Core Promoter ◽

Orphan Nuclear Receptor ◽

Recognition Sequence ◽

Mobility Shift ◽

Adrenocortical Cells ◽

Gene Encoding ◽

Adult Rat ◽

Gel Mobility Shift

As part of its trophic action to maintain the steroidogenic capacity of adrenocortical cells, corticotropin (ACTH) increases the transcription of the cytochrome P-450 steroid hydroxylase genes, including the gene encoding steroid 21-hydroxylase (21-OHase). We previously identified several promoter elements that regulate 21-OHase gene expression in mouse Y1 adrenocortical tumor cells. One of these elements, located at nucleotide -65, closely resembles the recognition sequence of the orphan nuclear receptor NGFI-B, suggesting that NGFI-B regulates this essential steroidogenic enzyme. To explore this possibility, we first used in situ hybridization to demonstrate high levels of NGFI-B transcripts in the adrenal cortex of the adult rat. In cultured mouse Y1 adrenocortical cells, treatment with ACTH, the major regulator of 21-OHase transcription, rapidly increased NGFI-B expression. Gel mobility shift and DNase I footprinting experiments showed that recombinantly expressed NGFI-B interacts specifically with the 21-OHase -65 element and identified one complex formed by Y1 extracts and the 21-OHase -65 element that contains NGFI-B. Expression of NGFI-B significantly augmented the activity of the intact 21-OHase promoter, while mutations of the -65 element that abolish NGFI-B binding markedly diminished NGFI-B-mediated transcriptional activation. Specific mutations of NGFI-B shown previously to impair either DNA binding or transcriptional activation diminished the effect of NGFI-B coexpression on 21-OHase expression. Finally, an oligonucleotide containing the NGFI-B response element conferred ACTH response to a core promoter from the prolactin gene, showing that this element is sufficient for ACTH induction. Collectively, these results identify a cellular promoter element that is regulated by NGFI-B and implicate NGFI-B in the transcriptional induction of 21-OHase by ACTH.

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The nuclear receptor steroidogenic factor 1 acts at multiple levels of the reproductive axis.

Genes & Development ◽

10.1101/gad.8.19.2302 ◽

1994 ◽

Vol 8 (19) ◽

pp. 2302-2312 ◽

Cited By ~ 398

Author(s):

H A Ingraham ◽

D S Lala ◽

Y Ikeda ◽

X Luo ◽

W H Shen ◽

...

Keyword(s):

Nuclear Receptor ◽

Steroidogenic Factor 1 ◽

Reproductive Axis ◽

Multiple Levels

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Pituitary homeobox 1 (Pitx1) stimulates rat LHβ gene expression via two functional DNA-regulatory regions

Journal of Molecular Endocrinology ◽

10.1677/jme.1.01754 ◽

2005 ◽

Vol 35 (1) ◽

pp. 145-158 ◽

Cited By ~ 14

Author(s):

Qiaorong Jiang ◽

Kyeong-Hoon Jeong ◽

Cheryl D Horton ◽

Lisa M Halvorson

Keyword(s):

Gene Expression ◽

Molecular Mechanisms ◽

Gene Promoter ◽

Orphan Nuclear Receptor ◽

Mobility Shift ◽

Regulatory Regions ◽

Steroidogenic Factor 1 ◽

Reproductive Axis ◽

Functional Dna ◽

Mobility Shift Assay

Luteinizing hormone (LH) plays a central role in the reproductive axis, stimulating both gonadal steroid biosynthesis and the development of mature gametes. Over the past decade, significant progress has been made in characterizing the transcription factors and associated DNA-regulatory sites which mediate expression of the LH β-subunit gene (LHβ). One of these factors, pituitary homeobox 1 (Pitx1), has been shown to stimulate LHβ gene promoter activity, both alone and in synergy with the orphan nuclear receptor, steroidogenic factor-1 (SF-1), and the early growth response gene 1 (Egr-1). Prior reports have attributed the Pitx1 response to a cis-element located at position -101 in the rat LHβ gene promoter. While investigating the role of Pitx1 in regulating rat LHβ gene expression, we observed a small, but significant, residual Pitx1 response despite mutation or deletion of this site. In the studies presented here, we identify the presence of a second functional Pitx1 region spanning positions −73 to −52 in the rat LHβ gene promoter. Based on electrophoretic mobility shift assay, Pitx1 binds to both the initially described 5′Pitx1 site as well as this putative 3′Pitx1 region. In transient transfection analysis, mutation of the LHβ-3′Pitx1 site significantly blunted Pitx1 responsiveness, with elimination of the Pitx1 response in a construct containing mutations in both Pitx1 cis-elements. We also analyzed the importance of each of these Pitx1 sites for providing functional synergy with SF-1 and with Egr-1. We observed a markedly decreased synergistic response with mutation of the 5′Pitx1 site with further loss following mutation of the 3′Pitx1 site. In contrast, functional interaction between Pitx1 and Egr-1 persisted with mutation of both Pitx1 regions. We conclude that Pitx1 stimulates the rat LHβ gene promoter via two Pitx1 DNA-regulatory regions. These results further our understanding of the molecular mechanisms that regulate expression of this critical reproductive gene promoter.

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