High-throughput splicing assays identify missense and silent splice-disruptive POU1F1 variants underlying pituitary hormone deficiency.

Pituitary hormone deficiency occurs in ∼1:4,000 live births. Approximately 3% of the cases are due to mutations in the alpha isoform of POU1F1, a pituitary-specific transcriptional activator. We found four separate heterozygous missense variants in unrelated individuals with hypopituitarism that were predicted to affect a minor isoform, POU1F1 beta, which can act as a transcriptional repressor. These variants retain repressor activity, but they shift splicing to favor the expression of the beta isoform, resulting in dominant-negative loss of function. Using a high-throughput splicing reporter assay, we tested 1,070 single-nucleotide variants in POU1F1. We identified 96 splice-disruptive variants, including 14 synonymous variants. In separate cohorts, we found two additional synonymous variants nominated by this screen that co-segregate with hypopituitarism. This study underlines the importance of evaluating the impact of variants on splicing and provides a catalog for interpretation of variants of unknown significance in POU1F1.

Otx2b mutant zebrafish have pituitary, eye and mandible defects that model mammalian disease.

Combined pituitary hormone deficiency (CPHD) is a genetically heterogeneous disorder caused by mutations in over 30 genes. The loss-of-function mutations in many of these genes, including orthodenticle homeobox 2 (OTX2), can present with a broad range of clinical symptoms, which provides a challenge for predicting phenotype from genotype. Another challenge in human genetics is functional evaluation of rare genetic variants that are predicted to be deleterious. Zebrafish are an excellent vertebrate model for evaluating gene function and disease pathogenesis, especially because large numbers of progeny can be obtained, overcoming the challenge of individual variation. To clarify the utility of zebrafish for the analysis of CPHD-related genes, we analyzed the effect of OTX2 loss of function in zebrafish. The otx2b gene is expressed in the developing hypothalamus, and otx2bhu3625/hu3625 fish exhibit multiple defects in the development of head structures and are not viable past 10 days post fertilization (dpf). Otx2bhu3625/hu3625 fish have a small hypothalamus and low expression of pituitary growth hormone and prolactin (prl). The gills of otx2bhu3625/hu3625 fish have weak sodium influx, consistent with the role of prolactin in osmoregulation. The otx2bhu3625/hu3625 eyes are microphthalmic with colobomas, which may underlie the inability of the mutant fish to find food. The small pituitary and eyes are associated with reduced cell proliferation and increased apoptosis evident at 3 and 5 dpf, respectively. These observations establish the zebrafish as a useful tool for the analysis of CPHD genes with variable and complex phenotypes.

[Genetic factors in hypopituitarism. The role of transcription factors in pituitary hormone deficiency]. / Genetikai tényezok a hypopituitarismus kialakulásában. A transzkripciós faktorok szerepe az agyalapimirigy-elégtelenség hátterében.

Developmental disorders affecting the hypothalamic-pituitary system can result in pituitary hormone deficiency showing a diverse clinical presentation. A significant majority of these disorders are closely linked to defects in transcription factor genes which play a major role in pituitary development. Those affecting the early phase of organogenesis typically lead to complex conditions affecting the pituitary as well as structures in the central nervous system. Transcription factors involved in the late phase can result in combined but rarely isolated pituitary hormone deficiency without extra-pituitary manifestation. Identifying the defects in these pituitary transcription factor genes may provide a useful tool in predicting disease progression as well as screening family members. Several pituitary transcription factors can be detected in the adult gland as well which is strongly emphasized in the World Health Organization's most recent guideline for pituitary tumor classification. Our review summarizes the current essential knowledge relevant for clinical endocrinologists. Orv Hetil. 2018; 159(7): 278-284.

The pattern of congenital heart defects arising from reduced Tbx5 expression is altered in a Down syndrome mouse model.

BACKGROUND: Nearly half of all individuals with Down Syndrome (DS) have some type of congenital heart defect (CHD), suggesting that DS sensitizes to CHD but does not cause it. We used a common mouse model of DS, the Ts65Dn mouse, to study the contribution of Tbx5, a known modifier of CHD, to heart defects on a trisomic backgroun. Mice that were heterozygous for a Tbx5 null allele were crossed with Ts65Dn mice. Thoraxes of progeny were fixed in 10% formalin, embedded in paraffin, and sectioned for analysis of CHD. Gene expression in embryonic hearts was examined by quantitative PCR and in situ hybridization. A TBX5 DNA binding site was verified by luciferase assays. METHODS: Mice that were heterozygous for a Tbx5 null allele were crossed with Ts65Dn mice. Thoraxes of progeny were fixed in 10% formalin, embedded in paraffin, and sectioned for analysis of CHD. Gene expression in embryonic hearts was examined by quantitative PCR and in situ hybridization. A TBX5 DNA binding site was verified by luciferase assays. RESULTS: We crossed mice that were heterozygous for a Tbx5 null allele with Ts65Dn mice. Mice that were trisomic and carried the Tbx5 mutation (Ts65Dn;Tbx5 (+/-) ) had a significantly increased incidence of overriding aorta compared to their euploid littermates. Ts65Dn;Tbx5 (+/-) mice also showed reduced expression of Pitx2, a molecular marker for the left atrium. Transcript levels of the trisomic Adamts1 gene were decreased in Tbx5 (+/-) mice compared to their euploid littermates. Evidence of a valid binding site for TBX5 upstream of the trisomic Adamts1 locus was also shown. CONCLUSION: Haploinsufficiency of Tbx5 and trisomy affects alignment of the aorta and this effect may stem from deviations from normal left-right patterning in the heart. We have unveiled a previously unknown interaction between the Tbx5 gene and trisomy, suggesting a connection between Tbx5 and trisomic genes important during heart development.

Homozygous CDH2 variant may be associated with hypopituitarism without neurological disorders.

Context: Congenital hypopituitarism is a genetically heterogeneous condition. Whole exome sequencing (WES) is a promising approach for molecular diagnosis of patients with this condition. Objectives: The aim of this study is to conduct WES in a patient with congenital hypopituitarism born to consanguineous parents, CDH2 screening in a cohort of patients with congenital hypopituitarism, and functional testing of a novel CDH2 variant. Design: Genomic DNA from a proband and her consanguineous parents was analyzed by WES. Copy number variants were evaluated. The genetic variants were filtered for population frequency (ExAC, 1000 genomes, gnomAD, and ABraOM), in silico prediction of pathogenicity, and gene expression in the pituitary and/or hypothalamus. Genomic DNA from 145 patients was screened for CDH2 by Sanger sequencing. Results: One female patient with deficiencies in growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, luteinizing hormone, and follicle-stimulating hormone and ectopic posterior pituitary gland contained a rare homozygous c.865G>A (p.Val289Ile) variant in CDH2. To determine whether the p.Val289Ile variant in CDH2 affects cell adhesion properties, we stably transfected L1 fibroblast lines, labeled the cells with lipophilic dyes, and quantified aggregation. Large aggregates formed in cells expressing wildtype CDH2, but aggregation was impaired in cells transfected with variant CDH2 or non-transfected. Conclusion: A homozygous CDH2 allelic variant was found in one hypopituitarism patient, and the variant impaired cell aggregation function in vitro. No disease-causing variants were found in 145 other patients screened for CDH2 variants. Thus, CDH2 is a candidate gene for hypopituitarism that needs to be tested in different populations. Significance statement: A female patient with hypopituitarism was born from consanguineous parents and had a homozygous, likely pathogenic, CDH2 variant that impairs cell aggregation in vitro. No other likely pathogenic variants in CDH2 were identified in 145 hypopituitarism patients.

Increased total scavenger capacity and decreased liver fat content in rats fed dehydroepiandrosterone and its sulphate on a high-fat diet.

BACKGROUND: Weak androgens have an antioxidant effect in vitro which is represented as a beneficial change in the antioxidant status. OBJECTIVE: Our aim was to clarify whether dehydroepiandrosterone (DHEA) and dehydroepiandrosterone-sulphate (DHEAS) oral administration results in beneficial antioxidant changes in Sprague-Dawley adult male rats in vivo. METHODS: Groups of experimental animals were fed a high-fat or a normal-fat diet and treated with DHEA or DHEAS in the drinking fluid. The control group was fed a high-fat diet together with untreated drinking fluid. Total scavenger capacity (TSC) was measured before and after 4 weeks of treatment in blood samples using a chemiluminometric assay. Fat content, superoxide dismutase (SOD), catalase and glutathione S-transferase (GST) activity in the liver were determined by Sudan staining and spectrophotometric assessments, respectively, from the fresh frozen tissue. RESULTS: DHEA and the DHEAS treatment showed significantly increased TSC in the groups fed a high-fat diet. The control group and the DHEA- or DHEAS-treated groups on normal diets showed no significant changes in TSC. The total score of liver fat content in the high-fat diet groups showed a marked positivity with Sudan staining, and the groups treated with DHEA or DHEAS had a markedly decreased amount of fat in the liver slides compared to the untreated group on the high-fat diet. Liver SOD activity was decreased in all high-fat diet groups and elevated only in the groups on a normal diet with DHEA or DHEAS treatment. Liver catalase and GST activities were decreased in the groups where TSC was significantly increased. CONCLUSION: Our results support the hypothesis that DHEA and DHEAS supplementation can improve the antioxidant status in lipid-rich dietary habits.

Murine SEC24D can substitute functionally for SEC24C during embryonic development.

The COPII component SEC24 mediates the recruitment of transmembrane cargos or cargo adaptors into newly forming COPII vesicles on the ER membrane. Mammalian genomes encode four Sec24 paralogs (Sec24a-d), with two subfamilies based on sequence homology (SEC24A/B and C/D), though little is known about their comparative functions and cargo-specificities. Complete deficiency for Sec24d results in very early embryonic lethality in mice (before the 8 cell stage), with later embryonic lethality (E7.5) observed in Sec24c null mice. To test the potential overlap in function between SEC24C/D, we employed dual recombinase mediated cassette exchange to generate a Sec24cc-d allele, in which the C-terminal 90% of SEC24C has been replaced by SEC24D coding sequence. In contrast to the embryonic lethality at E7.5 of SEC24C-deficiency, Sec24cc-d/c-d pups survive to term, though dying shortly after birth. Sec24cc-d/c-d pups are smaller in size, but exhibit no other obvious developmental abnormality by pathologic evaluation. These results suggest that tissue-specific and/or stage-specific expression of the Sec24c/d genes rather than differences in cargo export function explain the early embryonic requirements for SEC24C and SEC24D.

The phenotypic spectrum associated with OTX2 mutations in humans.

Objective: The transcription factor OTX2 is implicated in ocular, craniofacial, and pituitary development. Design: We aimed to establish the contribution of OTX2 mutations in congenital hypopituitarism patients with/without eye abnormalities, study functional consequences, and establish OTX2 expression in the human brain, with a view to investigate the mechanism of action. Methods: We screened patients from the UK (n = 103), international centres (n = 24), and Brazil (n = 282); 145 were within the septo-optic dysplasia spectrum, and 264 had no eye phenotype. Transactivation ability of OTX2 variants was analysed in murine hypothalamic GT1-7 neurons. In situ hybridization was performed on human embryonic brain sections. Genetically engineered mice were generated with a series of C-terminal OTX2 variants. Results: Two chromosomal deletions and six haploinsufficient mutations were identified in individuals with eye abnormalities; an affected relative of one patient harboured the same mutation without an ocular phenotype. OTX2 truncations led to significant transactivation reduction. A missense variant was identified in another patient without eye abnormalities; however, studies revealed it was most likely not causative. In the mouse, truncations proximal to aa219 caused anophthalmia, while distal truncations and the missense variant were tolerated. During human embryogenesis, OTX2 was expressed in the posterior pituitary, retina, ear, thalamus, choroid plexus, and partially in the hypothalamus, but not in the anterior pituitary. Conclusions: OTX2 mutations are rarely associated with hypopituitarism in isolation without eye abnormalities, and may be variably penetrant, even within the same pedigree. Our data suggest that the endocrine phenotypes in patients with OTX2 mutations are of hypothalamic origin.

Polymorphisms of the ApoE, HSD3B1, IL-1beta and p53 genes are associated with the development of early uremic complications in diabetic patients: results of a DNA resequencing array study.

Genetic polymorphisms of the genes involved in angiogenesis, the inflammatory cascade or apoptosis control can influence the chronic complications of diabetic patients. Parallel evaluation of multiple genetic polymorphisms became available with the development of DNA resequencing arrays. We aimed to develop a 16-gene, 18,859-nucleotide resequencing array to analyze the genetic background of uremic and gastrointestinal complications. DNA was isolated from 10 ml of peripheral blood of 41 non-uremic and 37 uremic patients with type II diabetes mellitus (DM); 32 suffering from gastric erosion complications. An Affymetrix Customseq Resequencing array was developed containing a total of 37 PCR products of selected genes. Confirmatory analysis was performed for 5 known polymorphisms by RFLP and for 4 others by capillary sequencing. Statistical analysis was performed using the Fisher's exact test. Correlations between the DNA resequencing array and the confirmatory methods were 96% for RFLP and 99.4% for capillary sequencing. The genetic polymorphisms of the ApoE, HSD3B1, IL-1beta and p53 genes were found to be significantly different (p<0.05) between the uremic and non-uremic diabetes group. In regards to the gastric erosion complications of the diabetic uremic patients, the A17708T polymorphism of the p53 intron 10 was found to have a statistically significant (p<0.05) role. In conclusion, DNA sequencing arrays can contribute to a multiparameter genetic analysis yielding highly correlating results using a single method in patients suffering type II DM.

Parathyroid hormone-dependent hypercalcemia.

The past fifteen years have resulted in great progress in our understanding of the pathogenesis and pathophysiology of hypercalcemic disorders occurring either sporadically or in a familial setting. This paper briefly reviews the clinically most important new knowledge on sporadic and hereditary forms of parathyroid hormone-dependent hypercalcemic disorders, with special emphasis on familial syndromes such as multiple endocrine neoplasia type 1 and type 2A, hyperparathyroidism-jaw tumor syndrome, familial isolated hyperparathyroidism, familial hypocalciuric hypercalcemia and neonatal severe primary hyperparathyroidism. In addition, the authors briefly present the most important clinical characteristics of 141 patients with parathyroid hormone-dependent hypercalcemia, including index patients of 18 families with hereditary disorders, diagnosed in a Hungarian endocrine center between 1997 and 2007.

[Extracellular calcium sensing under normal and pathological conditions]. / Az extracelluláris kalciumkoncentráció érzékelése egészséges és kóros állapotokban.

Ionic calcium has been known as an important intracellular second messenger for many decades. In addition, a whole series of experimental and clinical studies from the past fifteen years have provided evidence that extracellular ionic calcium itself is also a first messenger, since it is the ligand of a cell surface G-protein coupled receptor called calcium-sensing receptor. This review summarizes the current knowledge on the role of calcium-sensing receptor in the maintenance of calcium homeostasis, its functions in various tissues and some of the most important disorders characterized by defective calcium sensing. The inherited disorders of the calcium-sensing receptors may be classified as the results of loss-of-function and gain-of-function mutations of the calcium-sensing receptor gene. Loss-of-function heterozygous mutations lead to familial hypocalciuric hypercalcemia while homozygous mutations result in the frequently life-threatening disorder called neonatal severe hyperparathyroidism. Gain-of-function mutations of this receptor's gene cause the disorder called autosomal dominant hypocalcemia. The authors briefly highlight the clinical features, laboratory characteristics and therapeutic implications of these disorders. Also, they discuss briefly the molecular mechanisms resulting defective calcium-sensing in of patients with primary and secondary hyperparathyroidism, and summarize the results of some recent investigations on the functional consequences of genetic variants of the calcium-sensing receptor gene.

[Methods for the analysis of large gene deletions and their application in some hereditary diseases]. / A nagy géndeletiók kimutatásának módszerei és alkalmazásuk egyes örökletes betegségekben.

Complete or partial gene deletions and copy number variations of disease-causing genes have pathophysiological significance in several monogenic hereditary diseases. Direct DNA sequencing is not suitable for the detection of these genetic abnormalities. In this work, authors review methods of large gene deletion testing and present their own results in two monogenic diseases to demonstrate the application of current methods in clinical practice. Classical methods (chromosome banding, Southern-hybridisation, fluorescent in situ hybridisation), polymerase chain reaction-based techniques (denaturing high performance liquid chromatography, quantitative real-time polymerase chain reaction, microsatellite marker analysis, multiple amplifiable probe hybridisation, multiple ligation probe amplification) as well as techniques based on recent advances in bioinformatics (comparative genome hybridisation, array-based analysis) are presented. Finally, authors present their own findings on large deletion testing of the VHL gene using quantitative real-time polymerase chain reaction and multiple ligation probe amplification in patients with von Hippel-Lindau disease and review a simple polymerase chain reaction method for the detection of large deletion of the CYP21A2 gene in patients with congenital adrenal hyperplasia.

Pituitary Transcription Factor Mutations Leading to Hypopituitarism.

Congenital pituitary hormone deficiency is a disabling condition. It is part of a spectrum of disorders including craniofacial midline developmental defects ranging from holoprosencephaly through septo-optic dysplasia to combined and isolated pituitary hormone deficiency. The first genes discovered in the human disease were based on mouse models of dwarfism due to mutations in transcription factor genes. High-throughput DNA sequencing technologies enabled clinicians and researchers to find novel genetic causes of hypopituitarism for the more than three quarters of patients without a known genetic diagnosis to date. Transcription factor (TF) genes are at the forefront of the functional analysis of novel variants of unknown significance due to the relative ease in in vitro testing in a research lab. Genetic testing in hypopituitarism is of high importance to the individual and their family to predict phenotype composition, disease progression and to avoid life-threatening complications such as secondary adrenal insufficiency.This chapter aims to highlight our current understanding about (1) the contribution of TF genes to pituitary development (2) the diversity of inheritance and phenotype features in combined and select isolated pituitary hormone deficiency and (3) provide an initial assessment on how to approach variants of unknown significance in human hypopituitarism. Our better understanding on how transcription factor gene variants lead to hypopituitarism is a meaningful step to plan advanced therapies to specific genetic changes in the future.

Ser80Ile mutation and a concurrent Pro25Leu variant of the VHL gene in an extended Hungarian von Hippel-Lindau family.

Von Hippel-Lindau disease (VHL) is a rare autosomal dominant disease characterized by development of cystic and tumorous lesions at multiple sites, including the brain, spinal cord, kidneys, adrenals, pancreas, epididymis and eyes. The clinical phenotype results from molecular abnormalities of the VHL tumor suppressor gene, mapped to human chromosome 3p25-26. The VHL gene encodes two functionally active VHL proteins due to the presence of two translational initiation sites separated by 53 codons. The majority of disease-causing mutations have been detected downstream of the second translational initiation site, but there are conflicting data as to whether few mutations located in the first 53 codons, such as the Pro25Leu could have a pathogenic role. In this paper we report a large Hungarian VHL type 2 family consisting of 32 members in whom a disease-causing AGT80AAT (Ser80Ile) c.239G>A, p.Ser80Ile mutation, but not the concurrent CCT25CTT (Pro25Leu) c.74C>T, p.Pro25Leu variant co-segregated with the disease. To our knowledge, the Ser80Ile mutation has not been previously described in VHL type 2 patients with high risk of pheochromocytoma and renal cell cancer. Therefore, this finding represents a novel genotype-phenotype association and VHL kindreds with Ser80Ile mutation will require careful surveillance for pheochromocytoma. We concluded that the Pro25Leu variant is a rare, neutral variant, but the presence such a rare gene variant may make genetic counseling difficult.

Overrepresentation of the N363S variant of the glucocorticoid receptor gene in patients with bilateral adrenal incidentalomas.

CONTEXT: Some variants of the glucocorticoid receptor (GR) gene have been found to alter glucocorticoid sensitivity and have been associated with altered metabolic profiles. OBJECTIVE: The objective of the study was to examine whether N363S and ER22/23K variants of the GR gene may be associated with the development of adrenal incidentalomas and whether these variants may contribute to metabolic abnormalities frequently present in these patients. DESIGN, SETTING, AND PATIENTS: The study included 99 patients with unilateral and 44 patients with bilateral adrenal incidentalomas, 102 population-matched control subjects, and 100 patients with type 2 diabetes mellitus. MAIN OUTCOME MEASURES: Metabolic and hormonal parameters and GR gene variants were determined. RESULTS: When compared with control subjects, the carrier frequency for the N363S variant was markedly and significantly higher in patients with bilateral (7.8 vs. 20.5%, P < 0.05) but not in those with unilateral incidentalomas (7.1%) or in patients with type 2 diabetes (13.0%). Type 2 diabetes occurred more frequently in patients with bilateral, compared with those with unilateral incidentalomas (40.9 vs. 22.2%, P < 0.05). In patients with bilateral incidentalomas, a significant association of the N363S variant with impaired glucose homeostasis but not with body mass index, hypertension, hyperlipidemia, or history of coronary artery disease was found. The carrier frequency of the ER22/23EK variant was similar in all groups, and this variant failed to show any association with metabolic abnormalities. CONCLUSION: These results suggest that the N363S variant of the GR gene may play a role in the pathogenesis of bilateral adrenal incidentalomas, although the mechanism still remains to be investigated.

Detection of the Bcl I polymorphism of the glucocorticoid receptor gene by single-tube allele-specific polymerase chain reaction.

The Bcl I polymorphism of the glucocorticoid receptor gene, recently identified as an intronic C to G change 646 nucleotides downstream of exon 2, has been associated with increased sensitivity to glucocorticoids and its potential relevance in metabolic disturbances and in various disorders has been extensively investigated. In the present study, we designed a single-tube allele-specific polymerase chain reaction for genotyping this polymorphism in peripheral blood DNA samples. When the Bcl I polymorphism was detected with this novel method in a cohort of 247 healthy subjects, the observed genotype distribution matched the Hardy-Weinberg equilibrium (100 subjects homozygous for the wild-type, 124 heterozygous and 23 homozygous for the mutant allele). In 50 randomly selected subjects the Bcl I polymorphism was also determined using a traditional restriction fragment length polymorphism technique and DNA sequencing, and the results showed 100% coincidence with those obtained by our novel method. The method proved to be more rapid and less labour-intensive compared to currently used techniques, and it avoided the use of extensive instrumentals. We assume that this novel method may have a broad utility in clinical and molecular epidemiological studies aimed to elucidate the impact of the Bcl I polymorphism of the glucocorticoid receptor gene either on metabolic disturbances, or various disorders, including cancer treatment and hormone substitution therapies.

Genotype-phenotype correlations in Hungarian patients with hereditary medullary thyroid cancer.

The genotype and phenotype characteristics of Hungarian patients with RET proto-oncogene mutations operated on for hereditary medullary thyroid cancer (MTC) were studied. The genetic screening was performed in two centers and 40 patients with hereditary MTC or C-cell hyperplasia (CCH) from 18 unrelated families were analyzed. One patient having a mutation in exon 16 (Met918Thr) presented with the MEN2B phenotype, six patients from two families had hereditary MTC without pheochromocytoma (pheo) and primary hyperparathyroidism (PHPT), whereas 33 patients from 15 families showed the MEN2A phenotype. Two different mutations were identified in exon 10 (Cys609Tyr and Cys609Ser), five different mutations were present in exon 11 (Cys634Phe, Cys634Arg, Cys634Tyr, Cys634Trp and Cys634Ser), and two different mutations were localized in exon 14 (Val804Met and Val804Leu). Mutations in exon 10 were associated with hereditary MTC (Cys609Tyr) or with MEN2A syndrome (Cys609Ser). Mutations in exon 11 were always associated with the MEN2A phenotype. PHPT was present in one patient with mutation in exon 14 (Val804Met), whereas all other patients affected with mutations in exon 14 had hereditary MTC without PHPT and/or pheos.

[Nucleotide sequence variants of the glucocorticoid receptor gene and their significance in determining glucocorticoid sensitivity]. / A glükokortikoidreceptor gén szekvenciavariánsai és jelentoségük a glükokortikoidok iráinti érzékenység meghatározásában.

Nucleotide sequence variants of the glucocorticoid receptor gene and their significance in determining glucocorticoid sensitivity. The physiologic response and sensitivity to glucocorticoids may significantly differ among species, individuals, tissues and cell types. The variability of the effect of endogenous and exogenous glucocorticoids is largely determined by genetic components, of which the authors review the knowledge on the glucocorticoid receptor gene. The authors describe the genomic and non-genomic pathways of receptor function, the significance of isoforms produced during receptor protein formation, the pathomechanism of glucocorticoid resistance syndrome and the results of clinical investigations related to receptor gene polymorphisms. Through subtle alteration of receptor function, the gene polymorphisms may increase or diminish sensitivity to glucocorticoids and may play a role in the pathogenesis of metabolic disorders. In their own studies the authors found, that the N363S polymorphism, which increases glucocorticoid sensitivity, may play a role in the pathogenesis of bilateral adrenal adenomas, it may modify the clinical phenotype of patients with congenital adrenal hyperplasia, and may have an impact on steroid-induced ocular hypertension. It is presumed that further research in other diseases will continue to complete our knowledge on the pathophysiology of glucocorticoid receptor gene polymorphisms.

Gene Expression in Mouse Thyrotrope Adenoma: Transcription Elongation Factor Stimulates Proliferation.

Thyrotrope hyperplasia and hypertrophy are common responses to primary hypothyroidism. To understand the genetic regulation of these processes, we studied gene expression changes in the pituitaries of Cga(-/-) mice, which are deficient in the common α-subunit of TSH, LH, and FSH. These mice have thyrotrope hypertrophy and hyperplasia and develop thyrotrope adenoma. We report that cell proliferation is increased, but the expression of most stem cell markers is unchanged. The α-subunit is required for secretion of the glycoprotein hormone ß-subunits, and mutants exhibit elevated expression of many genes involved in the unfolded protein response, consistent with dilation and stress of the endoplasmic reticulum. Mutants have elevated expression of transcription factors that are important in thyrotrope function, such as Gata2 and Islet 1, and those that stimulate proliferation, including Nupr1, E2f1, and Etv5. We characterized the expression and function of a novel, overexpressed gene, transcription elongation factor A (SII)-like 5 (Tceal5). Stable expression of Tceal5 in a pituitary progenitor cell line is sufficient to increase cell proliferation. Thus, Tceal5 may act as a proto-oncogene. This study provides a rich resource for comparing pituitary transcriptomes and an analysis of gene expression networks.

ISL1-based LIM complexes control Slit2 transcription in developing cranial motor neurons.

LIM-homeodomain (HD) transcription factors form a multimeric complex and assign neuronal subtype identities, as demonstrated by the hexameric ISL1-LHX3 complex which gives rise to somatic motor (SM) neurons. However, the roles of combinatorial LIM code in motor neuron diversification and their subsequent differentiation is much less well understood. In the present study, we demonstrate that the ISL1 controls postmitotic cranial branchiomotor (BM) neurons including the positioning of the cell bodies and peripheral axon pathfinding. Unlike SM neurons, which transform into interneurons, BM neurons are normal in number and in marker expression in Isl1 mutant mice. Nevertheless, the movement of trigeminal and facial BM somata is stalled, and their peripheral axons are fewer or misrouted, with ectopic branches. Among genes whose expression level changes in previous ChIP-seq and microarray analyses in Isl1-deficient cell lines, we found that Slit2 transcript was almost absent from BM neurons of Isl1 mutants. Both ISL1-LHX3 and ISL1-LHX4 bound to the Slit2 enhancer and drove endogenous Slit2 expression in SM and BM neurons. Our findings suggest that combinations of ISL1 and LHX factors establish cell-type specificity and functional diversity in terms of motor neuron identities and/or axon development.