The roles of the nuclear receptor steroidogenic factor 1 in endocrine differentiation and development

Molecular mechanisms underlying adverse effects of dexamethasone and betamethasone in the developing cardiovascular system

Antenatal glucocorticoids accelerate fetal lung maturation and reduce mortality in preterm babies but can trigger adverse effects on the cardiovascular system. The mechanisms underlying off-target effects of the synthetic glucocorticoids mostly used, Dexamethasone (Dex) and Betamethasone (Beta), are unknown. We investigated effects of Dex and Beta on cardiovascular structure and function, and underlying molecular mechanism using the chicken embryo, an established model system to isolate effects of therapy on the developing heart and vasculature, independent of effects on the mother or placenta. Fertilized eggs were treated with Dex (0.1 mg kg-1 ), Beta (0.1 mg kg-1 ), or water vehicle (Control) on embryonic day 14 (E14, term = 21 days). At E19, biometry, cardiovascular function, stereological, and molecular analyses were determined. Both glucocorticoids promoted growth restriction, with Beta being more severe. Beta compared with Dex induced greater cardiac diastolic dysfunction and also impaired systolic function. While Dex triggered cardiomyocyte hypertrophy, Beta promoted a decrease in cardiomyocyte number. Molecular changes of Dex on the developing heart included oxidative stress, activation of p38, and cleaved caspase 3. In contrast, impaired GR downregulation, activation of p53, p16, and MKK3 coupled with CDK2 transcriptional repression linked the effects of Beta on cardiomyocyte senescence. Beta but not Dex impaired NO-dependent relaxation of peripheral resistance arteries. Beta diminished contractile responses to potassium and phenylephrine, but Dex enhanced peripheral constrictor reactivity to endothelin-1. We conclude that Dex and Beta have direct differential detrimental effects on the developing cardiovascular system.

Transcriptional inhibition of steroidogenic factor 1 in vivo in Oreochromis niloticus increased weight and suppressed gonad development

Steroidogenic factor 1 (sf1) (officially designated as nuclear receptor subfamily 5 group A member 1 [NR5A1]) is an important regulator of gonad development. Previous studies on sf1 in fish have been limited to cloning and in vitro expression experiments. In this study, we used antisense RNA to down-regulate sf1 transcription and sf1 protein expression. Down-regulation of sf1 resulted in an increase in body weight and inhibition of gonadal development in both males and females with the consequent lower gonadosomatic index compared to fish in the control group. Hematoxylin-eosin staining of the gonads of fish with down-regulated sf1 revealed fewer seminiferous tubules and sperm in the testis of males. In addition, the oocytes were mainly stage II and many of them were atretic follicle. We conducted comparative transcriptome and proteome analyses between the sf1-down-regulated group and the control group. These analyses revealed multiple gene-protein pairs and pathways involved in regulating the observed changes, including 44 and 74 differently expressed genes and proteins in males and females, respectively. The results indicated that dysfunctional retinal metabolism and fatty acid metabolism could be causes of the observed weight gain and gonad abnormalities in sf1-down-regulated fish. These findings demonstrate the feasibility of using antisense RNA for gene editing in fish. This methodology allows the study gene function in species less amenable to gene editing as for example aquaculture species with long life cycles.

Combined Antioxidant and Glucocorticoid Therapy for Safer Treatment of Preterm Birth

Ante- and postnatal glucocorticoid therapy reduces morbidity and mortality in the preterm infant, and it is therefore one of the best examples of the successful translation of basic experimental science into human clinical practice. However, accruing evidence derived from human clinical studies and from experimental studies in animal models raise serious concerns about potential long-term adverse effects of treatment on growth and neurological and cardiovascular function in the offspring. This review explores whether combined antioxidant and glucocorticoid therapy may be safer than glucocorticoid therapy alone for the treatment of preterm birth.

Haploinsufficiency of SF-1 Causes Female to Male Sex Reversal in Nile Tilapia, Oreochromis niloticus

Steroidogenic factor-1 (Sf-1) (officially designated nuclear receptor subfamily 5 group A member 1 [NR5A1]) is a master regulator of steroidogenesis and reproduction in mammals. However, its function remains unclear in nonmammalian vertebrates. In the present study, we used immunohistochemistry to detect expression of Sf-1 in the steroidogenic cells, the interstitial, granulosa, and theca cells of the ovary, and the Leydig cells of the testis, in Nile tilapia. Clustered regularly interspaced short palindromic repeats/CRISPR associated protein 9 (Cas9) cleavage of sf-1 resulted in a high mutation rate in the F0 generation and a phenotype of gonadal dysgenesis and reduced steroidogenic cells in XX and XY fish. Sf-1 deficiency also resulted in decreased cytochrome P450, family 19, subfamily A, polypeptide 1a, forkhead box L2 expression, and serum estradiol-17β in XX fish. In XY fish, Sf-1 deficiency increased cytochrome P450, family 19, subfamily A, polypeptide 1a and forkhead box L2 expression but decreased cytochrome P450, family 11, subfamily B, polypeptide 2 expression and serum 11-ketotestosterone levels. 17α-methyltestosterone treatment successfully rescued the gonadal phenotype of Sf-1-deficient XY fish, as demonstrated by normal spermatogenesis and production of F1 mutants. In contrast, estradiol-17β treatment only partially rescued the gonadal phenotype of Sf-1-deficient XX fish, as demonstrated by the appearance of phase II oocytes. Furthermore, both sf-1(+/-) F1 XX and XY mutants developed as fertile males, although spermatogenesis was delayed and efferent duct formation was disordered. Our data suggest that Sf-1 is a major regulator of steroidogenesis and reproduction in fish, as it is in mammals. Sf-1 deficiency resulted in gonadal dysgenesis and feminization of XY gonads. However, unlike in mammals, Sf-1 deficiency also resulted in female to male sex reversal in 8.1% of F0 and 92.1% of sf-1(+/-) F1 in XX fish.

Dicer deficiency reveals microRNAs predicted to control gene expression in the developing adrenal cortex

MicroRNAs (miRNAs) are small, endogenous, non-protein-coding RNAs that are an important means of posttranscriptional gene regulation. Deletion of Dicer, a key miRNA processing enzyme, is embryonic lethal in mice, and tissue-specific Dicer deletion results in developmental defects. Using a conditional knockout model, we generated mice lacking Dicer in the adrenal cortex. These Dicer-knockout (KO) mice exhibited perinatal mortality and failure of the adrenal cortex during late gestation between embryonic day 16.5 (E16.5) and E18.5. Further study of Dicer-KO adrenals demonstrated a significant loss of steroidogenic factor 1-expressing cortical cells that was histologically evident as early as E16.5 coincident with an increase in p21 and cleaved-caspase 3 staining in the cortex. However, peripheral cortical proliferation persisted in KO adrenals as assessed by staining of proliferating cell nuclear antigen. To further characterize the embryonic adrenals from Dicer-KO mice, we performed microarray analyses for both gene and miRNA expression on purified RNA isolated from control and KO adrenals of E15.5 and E16.5 embryos. Consistent with the absence of Dicer and the associated loss of miRNA-mediated mRNA degradation, we observed an up-regulation of a small subset of adrenal transcripts in Dicer-KO mice, most notably the transcripts coded by the genes Nr6a1 and Acvr1c. Indeed, several miRNAs, including let-7, miR-34c, and miR-21, that are predicted to target these genes for degradation, were also markedly down-regulated in Dicer-KO adrenals. Together these data suggest a role for miRNA-mediated regulation of a subset of genes that are essential for normal adrenal growth and homeostasis.

[Hypoplasia adrenal congenita of anencephalic type: two cases with pituitary abnormalities and review of literature]

Hypoplasia adrenal congenita is an extremely uncommon disease of early onset. This condition can be lethal in the absence of treatment. Some forms are due to the congenital adrenal hypoplasia of anencephalic type whose origin is even unknown. Here, we present two cases of congenital adrenal hypoplasia of anencephalic type with pituitary abnormalities. The two male newborns died because adrenal insufficiency in the neonatal period. The adrenal glands were hypoplastic with a histological structure of anencephalic type Immunocytochemical study of the pituitary revealed an absence of the gonadotrophs. No mutation of DAX 1 and SF-1 was found.

Pin1 facilitates the phosphorylation-dependent ubiquitination of SF-1 to regulate gonadotropin beta-subunit gene transcription

Pin1 is a peptidyl-prolyl cis-trans isomerase which catalyzes the isomerization of phosphorylated Ser/Thr-Pro peptide bonds. Pin1 knockout mice have marked abnormalities in their reproductive development and function. However, the molecular mechanisms underlying their reproductive defects are poorly understood. Herein, we demonstrate that Pin1 is required for both basal and GnRH-induced gonadotropin beta-subunit gene transcription, through interactions with the transcription factors SF-1, Pitx1, and Egr-1. Pin1 activates transcription of the gonadotropin beta-subunit genes synergistically with these transcription factors, either by modulating their stability or by increasing their protein-protein interactions. Notably, we provide evidence that Pin1 is required for the Ser203 phosphorylation-dependent ubiquitination of SF-1, which facilitates SF-1-Pitx1 interactions and therefore results in an enhancement of SF-1 transcriptional activity. Furthermore, we demonstrate that in gonadotrope cells, sufficient levels of activated Pin1 are maintained through transcriptional and posttranslational regulation by GnRH-induced signaling cascades. Our results suggest that Pin1 functions as a novel player in GnRH-induced signal pathways and is involved in gonadotropin beta-subunit gene transcription by modulating the activity of various specific transcription factors.

Regulation of cytochrome P450 by posttranslational modification

Cytochrome P450s are a family of enzymes represented in all kingdoms with expression in many species. Over 3,000 enzymes have been identified in nature. Humans express 57 putatively functional enzymes with a variety of critical physiological roles. They are involved in the metabolic oxidation, peroxidation, and reduction of many endogenous and exogenous compounds including xenobiotics, steroids, bile acids, fatty acids, eicosanoids, environmental pollutants, and carcinogens [Nelson, D. R., Kamataki, T., Waxman, D. J., Guengerich, F. P., Estabrook, R. W., Feyereisen, R., Gonzalez, F. J., Coon, M. J., Gunsalus, I. C., Gotoh, O. (1993) The P450 superfamily: update on new sequences, gene mapping, accession numbers, early trivial names of enzymes, and nomenclature. DNA Cell Biol. 12(1):1-51.] The development of numerous diseases and disorders including cancer and cardiovascular and endocrine dysfunction has been linked to P450s. Several levels of regulation, including transcription, translation, and posttranslational modification, participate in maintaining the proper function of P450s. Modifications including phosphorylation, glycosylation, nitration, and ubiquitination have been described for P450s. Their physiological significance includes modulation of enzyme activity, targeting to specific cellular compartments, and tagging for proteasomal degradation. Knowledge of P450 posttranslational regulation is derived from studies with relatively few enzymes. In many cases, there is only enough evidence to suggest the occurrence and a possible role for the modification. Thus, many P450 enzymes have not been fully characterized. With the introduction of current proteomics tools, we are primed to answer many important questions regarding regulation of P450 in response to a posttranslational modification. This review considers regulation of P450 in a context that describes the potential role and physiological significance of each modification.

DAX1 and its network partners: exploring complexity in development

DAX1 encoded by NR0B1, when mutated, is responsible for X-linked adrenal hypoplasia congenita (AHC). AHC is due to failure of the adrenal cortex to develop normally and is fatal if untreated. When duplicated, this gene is associated with an XY sex-reversed phenotype. DAX1 expression is present during development of the steroidogenic hypothalamic-pituitary-adrenal-gonadal (HPAG) axis and persists into adult life. Despite recognition of the crucial role for DAX1, its function remains largely undefined. The phenotypes of patients and animal models are complex and not always in agreement. Investigations using cell lines have proved difficult to interpret, possibly reflecting cell line choices and their limited characterization. We will review the efforts of our group and others to identify appropriate cell lines for optimizing ex vivo analysis of NR0B1 function throughout development. We will examine the role of DAX1 and its network partners in development of the hypothalamic-pituitary-adrenal/gonadal axis (HPAG) using a variety of different types of investigations, including those in model organisms. This network analysis will help us to understand normal and abnormal development of the HPAG. In addition, these studies permit identification of candidate genes for human inborn errors of HPAG development.

Ovarian granulosa cell tumors express a functional membrane receptor for anti-Müllerian hormone in transgenic mice

Anti-Müllerian hormone inhibits granulosa cell growth and function. Both anti-Müllerian hormone and its type II receptor are expressed in normal granulosa cells. We show by histologic and molecular analyses that ovarian tumors developing in transgenic mice, obtained by targeted oncogenesis using an anti-Müllerian hormone promoter-SV40 oncogene construct, are of granulosa-cell origin. Because tissue-specific, cell-surface molecules are of particular interest for the analysis and treatment of tumors, we examined the expression of anti-Müllerian hormone type II receptor in the ovaries of these transgenic mice. We demonstrate that the anti-Müllerian hormone type II receptor is expressed not only in normal ovarian follicles, but also in granulosa cell tumors. Using a cell line derived from one of these tumors, we show that the anti-Müllerian hormone type II receptor protein is present on the surface of tumor cells and binds anti-Müllerian hormone. Furthermore, we show that the anti-Müllerian hormone receptor is functional in the granulosa tumor cell line, with anti-Müllerian hormone treatment inducing selective activation of Smad1. In conclusion, in this study we present a new murine transgenic model of granulosa cell tumors of the ovary and, using this model, we demonstrate for the first time cell-surface expression of a highly tissue-specific molecule, anti-Müllerian hormone type II receptor, as well as the selective activation of Smad proteins by anti-Müllerian hormone, in granulosa tumor cells.

Developmental and hormonal regulation of murine scavenger receptor, class B, type 1

The scavenger receptor, class B, type I (SR-BI), is the predominant receptor that supplies plasma cholesterol to steroidogenic tissues in rodents. We showed previously that steroidogenic factor-1 (SF-1) binds a sequence in the human SR-BI promoter whose integrity is required for high-level SR-BI expression in cultured adrenocortical tumor cells. We now provide in vivo evidence that SF-1 regulates SR-BI. During mouse embryogenesis, SR-BI mRNA was initially expressed in the genital ridge of both sexes and persisted in the developing testes but not ovary. This sexually dimorphic expression profile of SR-BI expression in the gonads mirrors that of SF-1. No SR-BI mRNA was detected in the gonadal ridge of day 11.5 SF-1 knockout embryos. Both SR-BI and SF-1 mRNA were expressed in the cortical cells of the nascent adrenal glands. These studies directly support SF-1 participating in the regulation of SR-BI in vivo. We examined the effect of cAMP on SR-BI mRNA and protein in mouse adrenocortical (Y1-BS1) and testicular carcinoma Leydig (MA-10) cells. The time courses of induction were strikingly similar to those described for other cAMP- and SF-1-regulated genes. Addition of lipoproteins reduced SR-BI expression in Y1-BS1 cells, an effect that was reversed by administration of cAMP analogs. SR-BI mRNA and protein were expressed at high levels in the adrenal glands of knockout mice lacking the steroidogenic acute regulatory protein; these mice have extensive lipid deposits in the adrenocortical cells and high circulating levels of ACTH. Taken together, these studies suggest that trophic hormones can override the suppressive effect of cholesterol on SR-BI expression, thus ensuring that steroidogenesis is maintained during stress.

Characterization of the mouse Cyp1B1 gene. Identification of an enhancer region that directs aryl hydrocarbon receptor-mediated constitutive and induced expression

Transcriptional activation of the Cyp1B1 gene in rodents is stimulated by both polycyclic hydrocarbons and cAMP. The mouse Cyp1B1 gene structure contains three exons, of which the second nucleotide of exon 2 is the translation start site. Primer extension analysis identified a transcription start domain defining an exon 1 of 371 base pairs. The sequence 1.075 kilobases upstream of the transcription start site showed 11 xenobiotic-responsive elements (XRE) (TnGCGTG or GCGTG) that are putative aryl hydrocarbon receptor (AhR)-binding sites and three steroidogenic factor-1 motifs that are associated with cAMP-mediated transcriptional activation of genes. A transiently transfected Cyp1B1-luciferase construct, composed of exon 1 and 1.075 kilobases of 5'-flanking region, was induced by 2,3, 7,8-tetrachlorodibenzo-p-dioxin (TCDD; 10.0 +/- 3.0-fold, n = 6) in C3H10T1/2 cells, which exclusively express Cyp1B1. The 90-base pair basal promoter contains two SP-1 sites, one SF-1 site, and a TATA-like box. TCDD induction and basal expression were dependent on positive regulatory elements present between -1075 and -810. Five XRE motifs localized in the enhancer region were completely conserved between mouse and human CYP1B1 sequences. Similar inductions were seen in Hepa-1 cells, which express Cyp1A1 but not Cyp1B1. However, basal Cyp1B1 promoter activities were 4-10-fold higher in C3H10T1/2 cells providing the enhancer region was present, partially reproducing the in vivo cell-specific expression of Cyp1B1. Gel shift experiments established that TCDD stimulates AhR binding to the downstream XRE in the enhancer region. However, oligonucleotides that encompass two other XREs show a high affinity complex of similar size that is evident even without TCDD treatment and that does not contain either the AhR or AhR nuclear translocator. The fourth XRE is immediately adjacent to an E-box, and this oligonucleotide formed a smaller complex that was dependent on this E-box sequence. Negative regulatory sequences have been located between the promoter and TCDD-responsive enhancer regions. Constitutive expression of the Cyp1B1 gene was lost in AhR-deficient cells and was restored by transfected AhR cDNA. Reporter constructs function in a parallel manner, demonstrating the key role of the AhR in constitutive as well as TCDD-induced expression of Cyp1B1 in mouse embryo fibroblasts.

Regulation of the human P450scc gene by steroidogenic factor 1 is mediated by CBP/p300

Regulation of the human CYP11A gene encoding cytochrome P450scc, which catalyzes the first step of steroid synthesis, is regulated by many trans-acting transcription factors including steroidogenic factor 1 (SF-1). Transfection experiments in human adrenal NCI-H295 cells demonstrate regulation of the P450scc gene promoter region that contains several putative SF-1 binding sites. Cotransfection of SF-1 with a luciferase reporter construct containing the P450scc gene 5'-flanking region from nucleotides -1676 to +49 increased promoter activity, and deletion of the nucleotide sequence from position -1676 to -1620, which removes a putative cAMP response element (CRE), did not affect the stimulatory response to SF-1. As well, further deletion of the promoter region to nucleotide -110, which contains only one SF-1 binding site, still retained the ability to respond to exogenous SF-1. However, mutation of the remaining site which abolished SF-1 protein/DNA interaction also abrogated any functional response to the factor. All the P450scc reporter constructs which responded to SF-1 were further stimulated by exogenous p300 and CREB-binding protein (CBP), suggesting interaction between SF-1 and p300/CBP. As well, mutation of the binding site that abrogated the response to SF-1 also abolished the response to p300 and CBP. Cotransfection of the adenovirus E1A oncoprotein, which has been shown to interact with p300/CBP and interfere with its function, decreased the stimulatory effect of SF-1 and p300/CBP. Cotransfection of a mutated E1A protein, RG2, which does not interact with p300/CBP, did not alter the stimulatory effect of SF-1 and p300/CBP on the P450scc promoter. Deletion of the region from amino acid residues 2-67 in E1A, which has been postulated to interact with p300/CBP, also abolished the inhibitory effect of E1A, whereas deletion of the region from residues 120 to 140 had no effect. Two regions of CBP from amino acids 1 to 451 and from 1460 to 1891 were demonstrated to interact with SF-1 in vitro. Coexpression of fragments of the p300 protein fused to the VP16 protein in the presence of SF-1 and the -110 P450scc reporter construct indicated in vivo the interaction of two regions of p300 with SF-1, thus confirming the in vitro results. Taken together these results indicate that regulation of the human P450scc gene by SF-1 is mediated by p300/CBP. Due to the many putative roles of SF-1 to regulate many genes, its interaction with p300/CBP is potentially a key component effecting important physiological processes.

Receptors for anti-müllerian hormone on Leydig cells are responsible for its effects on steroidogenesis and cell differentiation

Strong overexpression of anti-Müllerian hormone (AMH) in transgenic mice leads to incomplete fetal virilization and decreased serum testosterone in the adult. Conversely, AMH-deficient mice exhibit Leydig cell hyperplasia. To probe the mechanism of action of AMH on Leydig cell steroidogenesis, we have studied the expression of mRNA for steroidogenic proteins in vivo and in vitro and performed a morphometric analysis of testicular tissue in mice overexpressing the hormone. We show that overexpression of AMH in male transgenic mice blocks the differentiation of Leydig cell precursors. Expression of steroidogenic protein mRNAs, mainly cytochrome P450 17 alpha-hydroxylase/C17-20 lyase (P450c17), is decreased in transgenic mice overexpressing AMH and in AMH-treated purified Leydig cells. In contrast, transgenic mice in whom the AMH locus has been disrupted show increase expression of P450c17. In vitro, but not in vivo, AMH also decreases the expression of the luteinizing hormone receptor. The effect of AMH is explained by the presence of its receptor on Leydig cells. Our results provide insight into the action of AMH as a negative modulator of Leydig cell differentiation and function.

A mouse Sertoli cell line expressing anti-Müllerian hormone and its type II receptor

Anti-Müllerian hormone (AMH) induces the regression of Müllerian ducts in the male foetus; it is secreted by prepubertal testicular Sertoli cells and repressed at puberty. Using an AMH promoter/Simian virus 40 (SV40) oncogene fusion gene, we generated transgenic mouse lines exhibiting heritable Sertoli cell tumorigenesis. One cell line, derived from an adult male, expressed mRNAs characteristic of mature Sertoli cells, but no AMH. Two other cell lines were obtained from pretumoral testes at 6.5 days. One was cloned to yield SMAT1, whose expression pattern was characteristic of prepubertal Sertoli cells, namely no transferrin and high SF-I and AMH expression. SMAT1 also secretes AMH protein into the culture medium and expresses the AMH receptor. To the best of our knowledge, this is the first Sertoli cell line stably expressing AMH and its receptor. Our results show that, in targeted oncogenesis, the timing of cell line derivation plays a critical role even when using a developmentally regulated promoter.

Expression of the estrogen-related receptor 1 (ERR-1) orphan receptor during mouse development

We studied the expression of the estrogen-related receptor 1 (ERR-1) during mouse embryonic development. ERR-1 is expressed at very early stages in ES cells and at E8.5 in the mesodermal cells of the visceral yolk sac. ERR-1 continues to be expressed later in mesodermal tissues and particularly in heart and in skeletal muscles. This expression persists during all the embryonic development and in adult stage. ERR-1 transcripts level increases during muscle differentiation. Accordingly, we show that ERR-1 expression increases during the myoblast to myotube transition in differentiating C2 myoblastic cells. ERR-1 has also been detected in the nervous system during embryonic development. At E10.5, a high level of ERR-1 transcripts can be observed in differentiated cells of the intermediate zone of the spinal cord which also suggests a role of ERR-1 in the differentiation of the nervous system. The same is observed in the telencephalon vesicules at E13.5. Later, at E15.5 and E17.5, expression persists in the spinal cord but decreases dramatically in the central nervous system. Moreover, ERR-1 expression increases during skin formation and is detected in the stratum spinosum which contains differentiated Malpighian cells. Finally, we also observed ERR-1 in endodermal derivatives such as the epithelium of intestine and urogenital system. The DNA target of ERR-1 has been identified to be the SF-1/FTZ-F1 responsive element (SFRE) and we show in this paper that SF-1/FTZ-F1 and ERR-1 bind to and activate transcription independently through the SFRE element. Our study suggests that ERR-1 may be implicated in numerous physiological or developmental functions, particularly in the muscle, the central and peripheral nervous system and the epidermis. Interestingly, in these various systems ERR-1 expression is correlated with post-mitotic cells stage, suggesting that ERR-1 may play a role in the differentiation process.

DAX1 gene expression upregulated by steroidogenic factor 1 in an adrenocortical carcinoma cell line

Two nuclear hormone receptor superfamily members, DAX1 and SF1, are required for normal adrenal cortical development. Mutations in DAX1 are responsible for X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism. Steroidogenic Factor 1 (SF1) regulates the expression of a number of steroidogenic genes and a putative SF1 response element (SF1-RE) in the DAX1 promoter which binds SF1 specifically. Therefore, we examined deletions in the DAX1 promoter driving expression of beta-galactosidase, with and without coexpression of SF1, in the human adrenocortical carcinoma cell line NCI-H295. We defined the DAX initiation start site and localized the putative SF1-RE at -135 to -143 bp. Loss of the putative SF1-RE region or specific removal of the 9-bp SF1 site resulted in decreased transcriptional activity by 2.3-to 2.5-fold. When cotransfected with 1550 bp of the DAX1 promoter, an SF1-containing expression vector increased the transcriptional activity of the DAX1 promoter by 4-fold. No significant change above baseline occurred when the cells were cotransfected with the 1541-bp fragment containing the entire 1550-bp promoter region minus the 9-bp SF1-RE. We conclude that the SF1-RE is an enhancer element within the DAX1 promoter and speculate that SF1 may be a transcription factor that acts, at least in part, through DAX1 for normal adrenal cortical development.

New developments in congenital lipoid adrenal hyperplasia and steroidogenic acute regulatory protein

To date, studies of patients with lipoid CAH have shown the indispensable role of StAR in the production of steroids by adrenal gland and gonads. Lipoid CAH is the first and so far only inborn disorder of steroid hormone synthesis and metabolism that is not caused by a defective steroidogenic enzyme but rather by a defect in cholesterol transport.