941 resultados para Angrp-1 gene
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Context and Objective: Main features of the autosomal dominant form of GH deficiency (IGHD II) include markedly reduced secretion of GH combined with low concentrations of IGF-I leading to short stature. Design, Setting, and Patients: A female patient presented with short stature (height -6.0 sd score) and a delayed bone age of 2 yr at the chronological age of 5 yr. Later, at the age of 9 yr, GHD was confirmed by standard GH provocation test, which revealed subnormal concentrations of GH and a very low IGF-I. Genetic analysis of the GH-1 gene revealed the presence of a heterozygous R178H mutation. Interventions and Results: AtT-20 cells coexpressing both wt-GH and GH-R178H showed a reduced GH secretion after forskolin stimulation compared with the cells expressing only wt-GH, supporting the diagnosis of IGHD II. Because reduced GH concentrations found in the circulation of our untreated patient could not totally explain her severe short stature, functional characterization of the GH-R178H performed by studies of GH receptor binding and activation of the Janus kinase-2/signal transducer and activator of transcription-5 pathway revealed a reduced binding affinity of GH-R178H for GH receptor and signaling compared with the wt-GH. Conclusion: This is the first report of a patient suffering from short stature caused by a GH-1 gene alteration affecting not only GH secretion (IGHD II) but also GH binding and signaling, highlighting the necessity of functional analysis of any GH variant, even in the alleged situation of IGHD II.
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Despite the differences in the main characteristics between the autosomal dominant form of GH deficiency (IGHD II) and the bioinactive GH syndrome, a common feature of both is their impact on linear growth leading to short stature in all affected patients.
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The human gene deleted in malignant brain tumors 1 (DMBT1) is considered to play a role in tumorigenesis and pathogen defense. It encodes a protein with multiple scavenger receptor cysteine-rich (SRCR) domains, which are involved in recognition and binding of a broad spectrum of bacterial pathogens. The SRCR domains are encoded by highly homologous repetitive exons, whose number in humans may vary from 8 to 13 due to genetic polymorphism. Here, we characterized the porcine DMBT1 gene on the mRNA and genomic level. We assembled a 4.5 kb porcine DMBT1 cDNA sequence from RT-PCR amplified seminal vesicle RNA. The porcine DMBT1 cDNA contains an open reading frame of 4050 nt. The transcript gives rise to a putative polypeptide of 1349 amino acids with a calculated mass of 147.9 kDa. Compared to human DMBT1, it contains only four N-terminal SRCR domains. Northern blotting revealed transcripts of approximately 4.7 kb in size in the tissues analyzed. Analysis of ESTs suggested the existence of secreted and transmembrane variants. The porcine DMBT1 gene spans about 54 kb on chromosome 14q28-q29. In contrast to the characterized cDNA, the genomic BAC clone only contained 3 exons coding for N-terminal SRCR domains. In different mammalian DMBT1 orthologs large interspecific differences in the number of SRCR exons and utilization of the transmembrane exon exist. Our data suggest that the porcine DMBT1 gene may share with the human DMBT1 gene additional intraspecific variations in the number of SRCR-coding exons.
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The majority of mutations that cause isolated GH deficiency type II (IGHD II) affect splicing of GH-1 transcripts and produce a dominant-negative GH isoform lacking exon 3 resulting in a 17.5-kDa isoform, which further leads to disruption of the GH secretory pathway. A clinical variability in the severity of the IGHD II phenotype depending on the GH-1 gene alteration has been reported, and in vitro and transgenic animal data suggest that the onset and severity of the phenotype relates to the proportion of 17.5-kDa produced. The removal of GH in IGHD creates a positive feedback loop driving more GH expression, which may itself increase 17.5-kDa isoform productions from alternate splice sites in the mutated GH-1 allele. In this study, we aimed to test this idea by comparing the impact of stimulated expression by glucocorticoids on the production of different GH isoforms from wild-type (wt) and mutant GH-1 genes, relying on the glucocorticoid regulatory element within intron 1 in the GH-1 gene. AtT-20 cells were transfected with wt-GH or mutated GH-1 variants (5'IVS-3 + 2-bp T->C; 5'IVS-3 + 6 bp T->C; ISEm1: IVS-3 + 28 G->A) known to cause clinical IGHD II of varying severity. Cells were stimulated with 1 and 10 mum dexamethasone (DEX) for 24 h, after which the relative amounts of GH-1 splice variants were determined by semiquantitative and quantitative (TaqMan) RT-PCR. In the absence of DEX, only around 1% wt-GH-1 transcripts were the 17.5-kDa isoform, whereas the three mutant GH-1 variants produced 29, 39, and 78% of the 17.5-kDa isoform. DEX stimulated total GH-1 gene transcription from all constructs. Notably, however, DEX increased the amount of 17.5-kDa GH isoform relative to the 22- and 20-kDa isoforms produced from the mutated GH-1 variants, but not from wt-GH-1. This DEX-induced enhancement of 17.5-kDa GH isoform production, up to 100% in the most severe case, was completely blocked by the addition of RU486. In other studies, we measured cell proliferation rates, annexin V staining, and DNA fragmentation in cells transfected with the same GH-1 constructs. The results showed that that the 5'IVS-3 + 2-bp GH-1 gene mutation had a more severe impact on those measures than the splice site mutations within 5'IVS-3 + 6 bp or ISE +28, in line with the clinical severity observed with these mutations. Our findings that the proportion of 17.5-kDa produced from mutant GH-1 alleles increases with increased drive for gene expression may help to explain the variable onset progression, and severity observed in IGHD II.
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Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is an autosomal recessive renal tubular disorder characterized by renal magnesium wasting, hypercalciuria, advanced nephrocalcinosis and progressive renal failure. Mutations in the paracellin-1 (CLDN16) gene have been defined as the underlying genetic defect. The tubular disorders and progression in renal failure are usually resistant to magnesium substitution and hydrochlorothiazide therapy, but hypomagnesemia may improve with advanced renal insufficiency. We present a patient with a homozygous truncating CLDN16 gene mutation (W237X) who had early onset of renal insufficiency despite early diagnosis at 2 months. He also had additional abnormalities including horseshoe kidney, neonatal teeth, atypical face, cardiac abnormalities including coarctation of the aorta associated with atrial and ventricular septal defects, umbilical hernia and hypertrichosis. To the best of our knowledge, this is the youngest case diagnosed as familial hypomagnesemia with hypercalciuria and nephrocalcinosis and the first case having such additional congenital abnormalities independent of the disease itself.
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BACKGROUND: Autosomal-dominant isolated GH deficiency (IGHD) is a rare disorder that is commonly believed to be due to heterozygous mutations in the GH-1 gene (GH-1). These mutations cause the production of a protein that affects the release of the product of the normal allele. Rarely, heterozygous mutations in the gene encoding for HESX-1 gene (HESX-1) may cause autosomal-dominant IGHD, with penetrance that has been shown to be variable in both humans and mice. SUBJECTS AND METHODS: We have sequenced the whole GH-1 in the index cases of 30 families with autosomal-dominant IGHD. In all the families other possible causes of GH deficiency and other pituitary hormones deficits were excluded. We here describe the clinical, biochemical and radiological picture of the families without GH-1 mutations. In these families, we also sequenced the HESX-1. RESULTS: The index cases of the five families with autosomal-dominant IGHD had normal GH-1, including the intronic sequences. They had no HESX-1 mutations. CONCLUSION: This study shows that GH-1 mutations are absent in 5/30 (16.6%) of the families with autosomal-dominant IGHD and raises the possibility that mutations in other gene(s) may be involved in IGHD with this mode of transmission.
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BACKGROUND: Interleukin-1 gene polymorphism (IL-1 gene) has been associated with periodontitis. The present study examined the subgingival microbiota by IL-1 gene status in subjects undergoing supportive periodontal therapy (SPT). METHODS: A total of 151 subjects with known IL-1 gene status (IL-1A +4845/IL-1B -3954) (IL-1 gene) were included in this study. Clinical data and subgingival plaque samples (40 taxa) were collected. These taxa were determined by the checkerboard DNA-DNA hybridization method. RESULTS: Gender, smoking habits (n-par tests), age, and clinical periodontal conditions did not differ by IL-1 gene status. IL-1 gene-negative subjects had a higher total bacterial load (mean difference, 480.4 x 10(5); 95% confidence interval [CI], 77 to 884 x 10(5); P <0.02). The levels of Actinobacillus actinomycetemcomitans (mean difference, 30.7 x 10(5); 95% CI, 2.2 to 59.5 x 10(5); P <0.05), Eubacterium nodatum (mean difference, 4.2 x 10(5); 95% CI, 0.6 to 7.8 x 10(5); P <0.02), Porphyromonas gingivalis (mean difference, 17.9 x 10(5); 95% CI, 1.2 to 34.5 x 10(5); P <0.05), and Streptococcus anginosus (mean difference, 4.0 x 10(5); 95% CI, 0.2 to 7.2 x 10(5); P <0.05) were higher in IL-1 gene-negative subjects, an observation specifically found at sites with probing depths <5.0 mm. CONCLUSIONS: Bleeding on probing did not differ by IL gene status, reflecting clinical SPT efficacy. IL-1 gene-negative subjects had higher levels of periodontal pathogens. This may suggest that among subjects undergoing SPT, a lower bacterial load is required in IL-1 gene-positive subjects to develop the same level of periodontitis as in IL-1 gene-negative subjects.
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CONTEXT: Thyroid transcription factor 1 (TITF1/NKX2.1) is expressed in the thyroid, lung, ventral forebrain, and pituitary. In the lung, TITF1/NKX2.1 activates the expression of genes critical for lung development and function. Titf/Nkx2.1(-/-) mice have pituitary and thyroid aplasia but also impairment of pulmonary branching. Humans with heterozygous TITF1/NKX2.1 mutations present with various combinations of primary hypothyroidism, respiratory distress, and neurological disorders. OBJECTIVE: The objective of the study was to report clinical and molecular studies of the first patient with lethal neonatal respiratory distress from a novel heterozygous TITF1/NKX2.1 mutation. Participant: This girl, the first child of healthy nonconsanguineous French-Canadian parents, was born at 41 wk. Birth weight was 3,460 g and Apgar scores were normal. Soon after birth, she developed acute respiratory failure with pulmonary hypertension. At neonatal screening on the second day of life, TSH was 31 mU/liter (N <15) and total T(4) 245 nmol/liter (N = 120-350). Despite mechanical ventilation, thyroxine, surfactant, and pulmonary vasodilators, the patient died on the 40th day. RESULTS: Histopathology revealed pulmonary tissue with low alveolar counts. The thyroid was normal. Sequencing of the patient's lymphocyte DNA revealed a novel heterozygous TITF1/NKX2.1 mutation (I207F). This mutation was not found in either parent. In vitro, the mutant TITF-1 had reduced DNA binding and transactivation capacity. CONCLUSION: This is the first reported case of a heterozygous TITF1/NKX2.1 mutation leading to neonatal death from respiratory failure. The association of severe unexplained respiratory distress in a term neonate with mild primary hypothyroidism is the clue that led to the diagnosis.
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Cell differentiation are associated with activation of cell lineage-specific genes. The $LpS{\it 1}\beta$ gene of Lytechinus pictus is activated at the late cleavage stage. $LpS{\it 1}\beta$ transcripts accumulate exclusively in aboral ectoderm lineages. Previous studies demonstrated two G-string DNA-elements, proximal and distal G-strings, which bind to an ectoderm-enriched nuclear factor. In order to define the cis-elements which control positive expression of the $LpS{\it 1}\beta$ gene, the regulatory region from $-$108 to +17 bp of the $LpS{\it 1}\beta$ gene promoter was characterized. The ectoderm G-string factor binds to a G/C-rich region larger than the G-string itself and the binding of the G-string factor requires sequences immediately downstream from the G-string. These downstream sequences are essential for full promoter activity. In addition, only 108 bp of $LpS{\it 1}\beta\ 5\sp\prime$ flanking DNA drives $LpS{\it 1}\beta$ gene expression in aboral ectoderm/mesenchyme cells. Therefore, for positive control of $LpS{\it 1}\beta$ gene expression, two regions of 5$\sp\prime$ flanking DNA are required: region I from base pairs $-$762 to $-$511, and region II, which includes the G/C-rich element, from base pairs $-$108 to $-$61. A mesenchyme cell repressor element is located within region I.^ DNA-binding proteins play key roles in determination of cell differentiation. The zinc finger domain is a DNA-binding domain present in many transcription factors. Based on homologies in zinc fingers, a zinc finger-encoding gene, SpKrox-1, was cloned from S. purpuratus. The putative SpKrox-1 protein has all structural characteristics of a transcription factor: four zinc fingers for DNA binding; acidic domain for transactivation; basic domain for nuclear targeting; and leucine zipper for dimerization. SpKrox-1 RNA transcripts showed a transient expression pattern which correlates largely with early embryonic development. The spatial expression of SpKrox-1 mRNA was distributed throughout the gastrula and larva ectodermal wall. However, SpKrox-1 was not expressed in pigment cells. The SpKrox-1 gene is thus a marker of a subset of SMCs or ectoderm cells. The structural features, and the transient temporal and restricted spatial expression patterns suggest that SpKrox-1 plays a role in a specific developmental event. ^