Página 38 dos resultados de 4394 itens digitais encontrados em 0.011 segundos

‣ Differential effects of Best disease causing missense mutations on bestrophin-1 trafficking

Johnson, Adiv A.; Lee, Yong-Suk; Stanton, J. Brett; Yu, Kuai; Hartzell, Criss H.; Marmorstein, Lihua Y.; Marmorstein, Alan D.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
370.16887%
Mutations in bestrophin-1 (Best1) cause Best vitelliform macular dystrophy (BVMD), a dominantly inherited retinal degenerative disease. Best1 is a homo-oligomeric anion channel localized to the basolateral surface of retinal pigment epithelial (RPE) cells. A number of Best1 mutants mislocalize in Madin–Darby canine kidney (MDCK) cells. However, many proteins traffic differently in MDCK and RPE cells, and MDCK cells do not express endogenous Best1. Thus, effects of Best1 mutations on localization in MDCK cells may not translate to RPE cells. To determine whether BVMD causing mutations affect Best1 localization, we compared localization and oligomerization of Best1 with Best1 mutants V9M, W93C, and R218C. In MDCK cells, Best1 and Best1R218C were basolaterally localized. Best1W93C and Best1V9M accumulated in cells. In cultured fetal human retinal pigment epithelium cells (fhRPE) expressing endogenous Best1, Best1R218C and Best1W93C were basolateral. Best1V9M was intracellular. All three mutants exhibited similar fluorescence resonance energy transfer (FRET) efficiencies to, and co-immunoprecipitated with Best1, indicating unimpaired oligomerization. When human Best1 was expressed in RPE in mouse eyes it was basolaterally localized. However...

‣ Mutations in FAM111B Cause Hereditary Fibrosing Poikiloderma with Tendon Contracture, Myopathy, and Pulmonary Fibrosis

Mercier, Sandra; Küry, Sébastien; Shaboodien, Gasnat; Houniet, Darren T.; Khumalo, Nonhlanhla P.; Bou-Hanna, Chantal; Bodak, Nathalie; Cormier-Daire, Valérie; David, Albert; Faivre, Laurence; Figarella-Branger, Dominique; Gherardi, Romain K.; Glen,
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em 05/12/2013 Português
Relevância na Pesquisa
370.16887%
Congenital poikiloderma is characterized by a combination of mottled pigmentation, telangiectasia, and epidermal atrophy in the first few months of life. We have previously described a South African European-descent family affected by a rare autosomal-dominant form of hereditary fibrosing poikiloderma accompanied by tendon contracture, myopathy, and pulmonary fibrosis. Here, we report the identification of causative mutations in FAM111B by whole-exome sequencing. In total, three FAM111B missense mutations were identified in five kindreds of different ethnic backgrounds. The mutation segregated with the disease in one large pedigree, and mutations were de novo in two other pedigrees. All three mutations were absent from public databases and were not observed on Sanger sequencing of 388 ethnically matched control subjects. The three single-nucleotide mutations code for amino acid changes that are clustered within a putative trypsin-like cysteine/serine peptidase domain of FAM111B. These findings provide evidence of the involvement of FAM111B in congenital poikiloderma and multisystem fibrosis.

‣ Mutations in the interleukin receptor IL11RA cause autosomal recessive Crouzon-like craniosynostosis

Keupp, Katharina; Li, Yun; Vargel, Ibrahim; Hoischen, Alexander; Richardson, Rebecca; Neveling, Kornelia; Alanay, Yasemin; Uz, Elif; Elcioğlu, Nursel; Rachwalski, Martin; Kamaci, Soner; Tunçbilek, Gökhan; Akin, Burcu; Grötzinger, Joachim; Konas, Ersoy
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
370.16887%
We have characterized a novel autosomal recessive Crouzon-like craniosynostosis syndrome in a 12-affected member family from Antakya, Turkey, the presenting features of which include: multiple suture synostosis, midface hypoplasia, variable degree of exophthalmos, relative prognathism, a beaked nose, and conductive hearing loss. Homozygosity mapping followed by targeted next-generation sequencing identified a c.479+6T>G mutation in the interleukin 11 receptor alpha gene (IL11RA) on chromosome 9p21. This donor splice-site mutation leads to a high percentage of aberrant IL11RA mRNA transcripts in an affected individual and altered mRNA splicing determined by in vitro exon trapping. An extended IL11RA mutation screen was performed in a cohort of 79 patients with an initial clinical diagnosis of Crouzon syndrome, pansynostosis, or unclassified syndromic craniosynostosis. We identified mutations segregating with the disease in five families: a German patient of Turkish origin and a Turkish family with three affected sibs all of whom were homozygous for the previously identified IL11RA c.479+6T>G mutation; a family with pansynostosis with compound heterozygous missense mutations, p.Pro200Thr and p.Arg237Pro; and two further Turkish families with Crouzon-like syndrome carrying the homozygous nonsense mutations p.Tyr232* and p.Arg292*. Using transient coexpression in HEK293T and COS7 cells...

‣ Functional Characterization of ABCB4 Mutations Found in Low Phospholipid-Associated Cholelithiasis (LPAC)

Kim, Tae Hee; Park, Hyo Jin; Choi, Ji Ha
Fonte: The Korean Physiological Society and The Korean Society of Pharmacology Publicador: The Korean Physiological Society and The Korean Society of Pharmacology
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
370.16887%
Multidrug resistance 3 (MDR3) is expressed on the canalicular membrane of the hepatocytes and plays an important role in protecting the liver from bile acids. Altered ABCB4 gene expression can lead to a rare hepatic disease, low phospholipid-associated cholelithiasis (LPAC). In this study, we characterized 3 ABCB4 mutations in LPAC patients using various in vitro assay systems. We first measured the ability of each mutant to transport paclitaxel and then the mechanisms by which these mutations might change MDR3 transport activity were determined using immunoblotting, cell surface protein biotinylation, and immunofluorescence. Through a membrane vesicular transport assay, we observed that the uptake of paclitaxel was significantly reduced in membrane vesicles expressing 2 ABCB4 mutations, F165I and S320F. Both mutants showed significantly decreased total and cell surface MDR3 expression. These data suggest two missense mutations of ABCB4 may alter function of MDR3 and ultimately can be determined as LPAC-causing mutations.

‣ Frequent Mutations in EGFR, KRAS and TP53 Genes in Human Lung Cancer Tumors Detected by Ion Torrent DNA Sequencing

Cai, Xin; Sheng, Jianhui; Tang, Chuanning; Nandakumar, Vijayalakshmi; Ye, Hua; Ji, Hong; Tang, Haiying; Qin, Yu; Guan, Hongwei; Lou, Feng; Zhang, Dandan; Sun, Hong; Dong, Haichao; Zhang, Guangchun; Liu, Zhiyuan; Dong, Zhishou; Guo, Baishuai; Yan, He; Yan,
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 23/04/2014 Português
Relevância na Pesquisa
370.16887%
Lung cancer is the most common malignancy and the leading cause of cancer deaths worldwide. While smoking is by far the leading cause of lung cancer, other environmental and genetic factors influence the development and progression of the cancer. Since unique mutations patterns have been observed in individual cancer samples, identification and characterization of the distinctive lung cancer molecular profile is essential for developing more effective, tailored therapies. Until recently, personalized DNA sequencing to identify genetic mutations in cancer was impractical and expensive. The recent technological advancements in next-generation DNA sequencing, such as the semiconductor-based Ion Torrent sequencing platform, has made DNA sequencing cost and time effective with more reliable results. Using the Ion Torrent Ampliseq Cancer Panel, we sequenced 737 loci from 45 cancer-related genes to identify genetic mutations in 76 human lung cancer samples. The sequencing analysis revealed missense mutations in KRAS, EGFR, and TP53 genes in the breast cancer samples of various histologic types. Thus, this study demonstrates the necessity of sequencing individual human cancers in order to develop personalized drugs or combination therapies to effectively target individual...

‣ ATP1A3 Mutations and Genotype-Phenotype Correlation of Alternating Hemiplegia of Childhood in Chinese Patients

Yang, Xiaoling; Gao, Hua; Zhang, Jie; Xu, Xiaojing; Liu, Xiaoyan; Wu, Xiru; Wei, Liping; Zhang, Yuehua
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/05/2014 Português
Relevância na Pesquisa
370.16887%
Alternating hemiplegia of childhood (AHC) is a rare and severe neurological disorder. ATP1A3 was recently identified as the causative gene. Here we report the first genetic study in Chinese AHC cohort. We performed whole-exome sequencing on three trios and three unrelated patients, and screened additional 41 typical cases and 100 controls by PCR-Sanger sequencing. ATP1A3 mutations were detected in 95.7% of typical AHC patients. At least 93.3% were de novo. Four late onset, atypical AHC patients were also mutation positive, suggesting the need for testing ATP1A3 mutations in atypical cases. Totally, 13 novel missense mutations (T370N, G706R, L770R, T771N, T771I, S772R, L802P, D805H, M806K, P808L, I810N, L839P and G893R) were identified in our study. By homology modeling of the mutant protein structures and calculation of an extensive list of molecular features, we identified two statistically significant molecular features, solvent accessibility and distance to metal ion, that distinguished disease-associated mutations from neutral variants. A logistic regression classifier achieved 92.9% accuracy by the average of 100 times of five-fold cross validations. Genotype-phenotype correlation analysis showed that patients with epilepsy were more likely to carry E815K mutation. In summary...

‣ A Gene-Specific Method for Predicting Hemophilia-Causing Point Mutations

Hamasaki-Katagiri, Nobuko; Salari, Raheleh; Wu, Andrew; Qi, Yini; Schiller, Tal; Filiberto, Amanda C.; Schisterman, Enrique F.; Komar, Anton A.; Przytycka, Teresa M.; Kimchi-Sarfaty, Chava
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
370.16887%
A fundamental goal of medical genetics is the accurate prediction of genotype–phenotype correlations. As an approach to develop more accurate in silico tools for prediction of disease-causing mutations of structural proteins, we present a gene- and disease-specific prediction tool based on a large systematic analysis of missense mutations from hemophilia A (HA) patients. Our HA-specific prediction tool, HApredictor, showed disease prediction accuracy comparable to other publicly available prediction software. In contrast to those methods, its performance is not limited to non-synonymous mutations. Given the role of synonymous mutations in disease and drug codon optimization, we propose that utilizing a gene- and disease-specific method can be highly useful to make functional predictions possible even for synonymous mutations. Incorporating computational metrics at both nucleotide and amino acid levels along with multiple protein sequence/structure alignment significantly improved the predictive performance of our tool. HApredictor is freely available for download at http://www.ncbi.nlm.nih.gov/CBBresearch/Przytycka/HA_Predict/index.htm.

‣ Rapid Detection of DNMT3A R882 Mutations in Hematologic Malignancies Using a Novel Bead-Based Suspension Assay with BNA(NC) Probes

Shivarov, Velizar; Ivanova, Milena; Naumova, Elissaveta
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 10/06/2014 Português
Relevância na Pesquisa
370.16887%
Mutations in the human DNA methyl transferase 3A (DNMT3A) gene are recurrently identified in several hematologic malignancies such as Philadelphia chromosome-negative myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), MPN/MDS overlap syndromes and acute myeloid leukemia (AML). They have been shown to confer worse prognosis in some of these entities. Notably, about 2/3 of these mutations are missense mutations in codon R882 of the gene. We aimed at the development and validation of a novel easily applicable in routine practice method for quantitative detection of the DNMT3A p.R882C/H/R/S mutations bead-based suspension assay. Initial testing on plasmid constructs showed excellent performance of BNA(NC)-modified probes with an optimal hybridization temperature of 66°C. The method appeared to be quantitative and showed sensitivity of 2.5% for different mutant alleles, making it significantly superior to direct sequencing. The assay was further validated on plasmid standards at different ratios between wild type and mutant alleles and on clinical samples from 120 patients with known or suspected myeloid malignancies. This is the first report on the quantitative detection of DNMT3A R882 mutations using bead-based suspension assay with BNA(NC)-modified probes. Our data showed that it could be successfully implemented in the diagnostic work-up for patients with myeloid malignancies...

‣ Cancer3D: understanding cancer mutations through protein structures

Porta-Pardo, Eduard; Hrabe, Thomas; Godzik, Adam
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
370.16887%
The new era of cancer genomics is providing us with extensive knowledge of mutations and other alterations in cancer. The Cancer3D database at http://www.cancer3d.org gives an open and user-friendly way to analyze cancer missense mutations in the context of structures of proteins in which they are found. The database also helps users analyze the distribution patterns of the mutations as well as their relationship to changes in drug activity through two algorithms: e-Driver and e-Drug. These algorithms use knowledge of modular structure of genes and proteins to separately study each region. This approach allows users to find novel candidate driver regions or drug biomarkers that cannot be found when similar analyses are done on the whole-gene level. The Cancer3D database provides access to the results of such analyses based on data from The Cancer Genome Atlas (TCGA) and the Cancer Cell Line Encyclopedia (CCLE). In addition, it displays mutations from over 14 700 proteins mapped to more than 24 300 structures from PDB. This helps users visualize the distribution of mutations and identify novel three-dimensional patterns in their distribution.

‣ Platinum: a database of experimentally measured effects of mutations on structurally defined protein–ligand complexes

Pires, Douglas E.V.; Blundell, Tom L.; Ascher, David B.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
370.16887%
Drug resistance is a major challenge for the treatment of many diseases and a significant concern throughout the drug development process. The ability to understand and predict the effects of mutations on protein–ligand affinities and their roles in the emergence of resistance would significantly aid treatment and drug design strategies. In order to study and understand the impacts of missense mutations on the interaction of ligands with the proteome, we have developed Platinum (http://structure.bioc.cam.ac.uk/platinum). This manually curated, literature-derived database, comprising over 1000 mutations, associates for the first time experimental information on changes in affinity with three-dimensional structures of protein–ligand complexes. To minimize differences arising from experimental techniques and to directly compare binding affinities, Platinum considers only changes measured by the same group and with the same amino-acid sequence used for structure determination, providing a direct link between protein structure, how a ligand binds and how mutations alter the affinity of the ligand of the protein. We believe Platinum will be an invaluable resource for understanding the effects of mutations that give rise to drug resistance...

‣ Mutations in the Satellite Cell Gene MEGF10 Cause a Recessive Congenital Myopathy with Minicores

Mahoney, Lane J.; Myers, Jennifer A.; Estrella, Elicia A.; Duncan, Anna R.; Dey, Friederike; DeChene, Elizabeth T.; Blasko-Goehringer, Jessica M.; Bönnemann, Carsten G.; Mendell, Jerry R.; Nishino, Ichizo; Boyden, Steven Edward; Kawahara, Genri; Mitsuhas
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
370.16887%
We ascertained a nuclear family in which three of four siblings were affected with an unclassified autosomal recessive myopathy characterized by severe weakness, respiratory impairment, scoliosis, joint contractures, and an unusual combination of dystrophic and myopathic features on muscle biopsy. Whole genome sequence from one affected subject was filtered using linkage data and variant databases. A single gene, MEGF10, contained nonsynonymous mutations that co-segregated with the phenotype. Affected subjects were compound heterozygous for missense mutations c.976T > C (p.C326R) and c.2320T > C (p.C774R). Screening the MEGF10 open reading frame in 190 patients with genetically unexplained myopathies revealed a heterozygous mutation, c.211C > T (p.R71W), in one additional subject with a similar clinical and histological presentation as the discovery family. All three mutations were absent from at least 645 genotyped unaffected control subjects. MEGF10 contains 17 atypical epidermal growth factor-like domains, each of which contains eight cysteine residues that likely form disulfide bonds. Both the p.C326R and p.C774R mutations alter one of these residues, which are completely conserved in vertebrates. Previous work showed that murine Megf10 is required for preserving the undifferentiated...

‣ Mutations in the JARID1C gene, which is involved in transcriptional regulation and chromatin remodeling, cause X-linked mental retardation

Jensen, L.R.; Amende, M.; Gurok, U.; Moser, B.; Gimmel, V.; Tzschach, A.; Janecke, A.; Tariverdian, G.; Chelly, J.; Fryns, J.P.; Van Esch, H.; Kleefstra, T.; Hamel, B.; Moraine, C.; Gecz, J.; Turner, G.; Reinhardt, R.; Kalscheuer, V.; Ropers, H.H.; Lenzer
Fonte: Univ Chicago Press Publicador: Univ Chicago Press
Tipo: Artigo de Revista Científica
Publicado em //2005 Português
Relevância na Pesquisa
370.16887%
In families with nonsyndromic X-linked mental retardation (NS-XLMR), >30% of mutations seem to cluster on proximal Xp and in the pericentric region. In a systematic screen of brain-expressed genes from this region in 210 families with XLMR, we identified seven different mutations in JARID1C, including one frameshift mutation and two nonsense mutations that introduce premature stop codons, as well as four missense mutations that alter evolutionarily conserved amino acids. In two of these families, expression studies revealed the almost complete absence of the mutated JARID1C transcript, suggesting that the phenotype in these families results from functional loss of the JARID1C protein. JARID1C (Jumonji AT-rich interactive domain 1C), formerly known as “SMCX,” is highly similar to the Y-chromosomal gene JARID1D/SMCY, which encodes the H-Y antigen. The JARID1C protein belongs to the highly conserved ARID protein family. It contains several DNA-binding motifs that link it to transcriptional regulation and chromatin remodeling, processes that are defective in various other forms of mental retardation. Our results suggest that JARID1C mutations are a relatively common cause of XLMR and that this gene might play an important role in human brain function.; Lars Riff Jensen...

‣ Heterozygous HESX1 mutations associated with isolated congenital pituitary hypoplasia and septo-optic dysplasia

Thomas, P.; Dattani, M.; Brickman, J.; McNay, D.; Warne, G.; Zacharin, M.; Cameron, F.; Hurst, J.; Woods, K.; Dunger, D.; Stanhope, R.; Forrest, S.; Robinson, I.; Beddington, R.
Fonte: Oxford Univ Press Publicador: Oxford Univ Press
Tipo: Artigo de Revista Científica
Publicado em //2001 Português
Relevância na Pesquisa
370.16887%
We have previously shown that familial septo-optic dysplasia (SOD), a syndromic form of congenital hypopituitarism involving optic nerve hypoplasia and agenesis of midline brain structures, is associated with homozygosity for an inactivating mutation in the homeobox gene HESX1/Hesx1 in man and mouse. However, as most SOD/congenital hypopituitarism occurs sporadically, the possible contribution of HESX1 mutations to the aetiology of these cases is presently unclear. Interestingly, a small proportion of mice heterozygous for the Hesx1 null allele show a milder SOD phenocopy, implying that heterozygous mutations in human HESX1 could underlie some cases of congenital pituitary hypoplasia with or without midline defects. Accordingly, we have now scanned for HESX1 mutations in 228 patients with a broad spectrum of congenital pituitary defects, ranging in severity from isolated growth hormone deficiency to SOD with panhypopituitarism. Three different heterozygous missense mutations were detected in individuals with relatively mild pituitary hypoplasia or SOD, which display incomplete penetrance and variable phenotype amongst heterozygous family members. Gel shift analysis of the HESX1-S170L mutant protein, which is encoded by the C509T mutated allele...

‣ Maroteaux-Lamy syndrome: Functional characterization of pathogenic mutations and polymorphisms in the arylsulfatase B gene

Garrido, E.; Cormand, B.; Hopwood, J.; Chabas, A.; Grinberg, D.; Vilageliu, L.
Fonte: Academic Press Inc Elsevier Science Publicador: Academic Press Inc Elsevier Science
Tipo: Artigo de Revista Científica
Publicado em //2008 Português
Relevância na Pesquisa
370.16887%
Mucopolysaccharidosis VI (MPS VI; Maroteaux-Lamy syndrome) is an autosomal recessive lysosomal disorder caused by deficiency of N-acetylgalactosamine-4-sulfatase (ARSB), which is required for the degradation of dermatan sulfate. We recently reported mutational screening of 12 Spanish and 4 Argentinian MPS VI patients. In the present study, seven missense mutations (c.245T>G [p.L82R], c.413A>G [p.Y138C], c.719C>T [p.S240F], c.922G>A [p.G308R], c.937C>G [p.P313A], c.1340G>T [p.C447F] and c.1415T>C [p.L472P]) were transiently expressed in COS-7 cells and 4-sulfatase activity was measured in cell extracts. All mutations resulted in less than 6% of wild-type enzyme activity, in most cases undetectable. Mutations were expressed in their original haplotype context with respect to two non-synonymous polymorphisms present in the ARSB protein, p.V358M and p.S384N. The three less frequent haplotype combinations yielded an ARSB activity of 16%, 57% and 70%, when compared to the most frequent haplotype (p.358V and p.384S). Western blot analyses showed that the expressed mutations significantly reduced the amount of mature protein. Sub-cellular localization studies of mutant ARSB proteins in fibroblasts of MPS VI patients were performed. RNA analysis confirmed that nonsense-mediated RNA decay had taken place for all mutant alleles (c.1143-1G>C...

‣ Identification and molecular characterization of α-L-iduronidase mutations present in mucopolysaccharidosis type I patients undergoing enzyme replacement therapy; Identification and molecular characterization of alpha-L-iduronidase mutations present in mucopolysaccharidosis type I patients undergoing enzyme replacement therapy

Yogalingam, G.; Guo, X.; Muller, V.; Brooks, D.; Clements, P.; Kakkis, E.; Hopwood, J.
Fonte: Wiley-Liss Publicador: Wiley-Liss
Tipo: Artigo de Revista Científica
Publicado em //2004 Português
Relevância na Pesquisa
370.16887%
Mucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disorder caused by a deficiency of alpha-L-iduronidase (IDUA). Mutations in the gene are responsible for the enzyme deficiency, which leads to the intralysosomal storage of the partially degraded glycosaminoglycans dermatan sulfate and heparan sulfate. Molecular characterization of MPS I patients has resulted in the identification of over 70 distinct mutations in the IDUA gene. The high degree of molecular heterogeneity reflects the wide clinical variability observed in MPS I patients. Six novel mutations, c.1087C>T (p.R363C), c.1804T>A (p.F602I), c.793G>C, c.712T>A (p.L238Q), c.1727+2T>A, and c.1269C>G (p.S423R), in a total of 14 different mutations, and 13 different polymorphic changes, including the novel c.246C>G (p.H82Q), were identified in a cohort of 10 MPS I patients enrolled in a clinical trial of enzyme-replacement therapy. Five novel amino acid substitutions and c.236C>T (p.A79V) were engineered into the wild-type IDUA cDNA and expressed. A p.G265R read-through mutation, arising from the c.793G>C splice mutation, was also expressed. Each mutation reduced IDUA protein and activity levels to varying degrees with the processing of many of the mutant forms also affected by IDUA. The varied properties of the expressed mutant forms of IDUA reflect the broad range of biochemical and clinical phenotypes of the 10 patients in this study. IDUA kinetic data derived from each patient's cultured fibroblasts...

‣ The CUL3–KLHL3 E3 ligase complex mutated in Gordon's hypertension syndrome interacts with and ubiquitylates WNK isoforms: disease-causing mutations in KLHL3 and WNK4 disrupt interaction

Ohta, Akihito; Schumacher, Frances-Rose; Mehellou, Youcef; Johnson, Clare; Knebel, Axel; Macartney, Thomas J.; Wood, Nicola T.; Alessi, Dario R.; Kurz, Thimo
Fonte: Portland Press Ltd. Publicador: Portland Press Ltd.
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
370.16887%
The WNK (with no lysine kinase)–SPAK (SPS1-related proline/alanine-rich kinase)/OSR1 (oxidative stress-responsive kinase 1) signalling pathway plays an important role in controlling mammalian blood pressure by modulating the activity of ion co-transporters in the kidney. Recent studies have identified Gordon's hypertension syndrome patients with mutations in either CUL3 (Cullin-3) or the BTB protein KLHL3 (Kelch-like 3). CUL3 assembles with BTB proteins to form Cullin–RING E3 ubiquitin ligase complexes. To explore how a CUL3–KLHL3 complex might operate, we immunoprecipitated KLHL3 and found that it associated strongly with WNK isoforms and CUL3, but not with other components of the pathway [SPAK/OSR1 or NCC (Na+/Cl− co-transporter)/NKCC1 (Na+/K+/2Cl− co-transporter 1)]. Strikingly, 13 out of the 15 dominant KLHL3 disease mutations analysed inhibited binding to WNK1 or CUL3. The recombinant wild-type CUL3–KLHL3 E3 ligase complex, but not a disease-causing CUL3–KLHL3[R528H] mutant complex, ubiquitylated WNK1 in vitro. Moreover, siRNA (small interfering RNA)-mediated knockdown of CUL3 increased WNK1 protein levels and kinase activity in HeLa cells. We mapped the KLHL3 interaction site in WNK1 to a non-catalytic region (residues 479–667). Interestingly...

‣ SAMHD1 Gene Mutations Are Associated with Cerebral Large-Artery Atherosclerosis

Li, Wei; Xin, Baozhong; Yan, Junpeng; Wu, Ying; Hu, Bo; Liu, Liping; Wang, Yilong; Ahn, Jinwoo; Skowronski, Jacek; Zhang, Zaiqiang; Wang, Yongjun; Wang, Heng
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
370.16887%
Background. To investigate whether one or more SAMHD1 gene mutations are associated with cerebrovascular disease in the general population using a Chinese stroke cohort. Methods. Patients with a Chinese Han background (N = 300) diagnosed with either cerebral large-artery atherosclerosis (LAA, n = 100), cerebral small vessel disease (SVD, n = 100), or other stroke-free neurological disorders (control, n = 100) were recruited. Genomic DNA from the whole blood of each patient was isolated, and direct sequencing of the SAMHD1 gene was performed. Both wild type and mutant SAMHD1 proteins identified from the patients were expressed in E. coli and purified; then their dNTPase activities and ability to form stable tetramers were analysed in vitro. Results. Three heterozygous mutations, including two missense mutations c.64C>T (P22S) and c.841G>A (p.E281K) and one splice site mutation c.696+2T>A, were identified in the LAA group with a prevalence of 3%. No mutations were found in the patients with SVD or the controls (p = 0.05). The mutant SAMHD1 proteins were functionally impaired in terms of their catalytic activity as a dNTPase and ability to assemble stable tetramers. Conclusions. Heterozygous SAMHD1 gene mutations might cause genetic predispositions that interact with other risk factors...

‣ Functional Characterization and Structural Modeling of Obesity Associated Mutations in the Melanocortin 4 Receptor

Tan, Karen; Pogozheva, Irina D.; Yeo, Giles S. H.; Hadaschik, Dirk; Keogh, Julia M.; Haskell-Leuvano, Carrie; O'Rahilly, Stephen; Mosberg, Henry I.; Farooqi, I. Sadaf
Fonte: The Endocrine Society Publicador: The Endocrine Society
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
370.16887%
Mutations in the melanocortin 4 receptor (MC4R) gene are the most common known cause of monogenic human obesity. The MC4R gene was sequenced in 2000 subjects with severe early-onset obesity. We detected seven different nonsense and 19 nonsynonymous mutations in a total of 94 probands, some of which have been reported previously by others. We functionally characterized the 11 novel obesity associated missense mutations. Seven of these mutants (L54P, E61K, I69T, S136P, M161T, T162I, and I269N) showed impaired cell surface trafficking, reduced level of maximal binding of the radioligand [125I]NDP-MSH, and reduced ability to generate cAMP in response to ligand. Four mutant MC4Rs (G55V, G55D, S136F, and A303T) displayed cell surface expression and agonist binding similar to the wild-type receptor but showed impaired cAMP production, suggesting that these residues are likely to be critical for conformational rearrangement essential for receptor activation. Homology modeling of these mutants using a model of MC4R based on the crystal structure of the β2-adrenoreceptor was used to provide insights into the possible structural basis for receptor dysfunction. Transmembrane (TM) domains 1, 3, 6, 7, and peripheral helix 8 appear to participate in the agonist-induced conformational rearrangement necessary for coupling of ligand binding to signaling. We conclude that G55V...

‣ Characterization of Nine Novel Mutations in the CD40 Ligand Gene in Patients with X-Linked Hyper IgM Syndrome of Various Ancestry

Macchi, Paolo; Villa, Anna; Strina, Dario; Sacco, Maria Grazia; Morali, Federica; Brugnoni, Duilio; Giliani, Silvia; Mantuano, Elide; Fasth, Anders; Andersson, Bengt; Zegers, Ben J. M.; Cavagni, Giovanni; Reznick, Igor; Levy, Jacov; Zan-Bar, Israel; Porat
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1995 Português
Relevância na Pesquisa
370.16887%
X-linked immunodeficiency with hyper-IgM (HIGMX-1) is a rare disorder caused by defective expression of the CD40 ligand (CD40L) by activated T lymphocytes, resulting in inefficient T-B cell cooperation and failure of B cells to undergo immunoglobulin isotype switch. In the present work, we describe nine patients of various ancestry who bear different mutations in the X chromosome–specific CD40L gene. Two of the mutations were nonsense mutations, one each resulting in premature stop codons at amino acid residues 39 and 140. Three patients had single point missense mutations, one each at codons 126, 140, and 144. Another patient had a 4-bp genomic deletion in exon 2, resulting in a frameshift and premature termination. Three patients showed insertions, one each of 1, 2, and 4 nt, probably because of polymerase slippage, resulting in frameshift mutation and premature termination. Overall, these observations confirm the heterogeneity of mutations in HIGMX-1. However, the identification of two patients whose mutation involves codon 140 (previously shown to be altered in two other unrelated subjects) suggests that this may be a hotspot of mutation in HIGMX-1. In two additional patients with clinical and immunological features indistinguishable from canonical HIGMX-1...

‣ The spectrum of mutations in TBX3: Genotype/Phenotype relationship in ulnar-mammary syndrome.

Bamshad, M; Le, T; Watkins, W S; Dixon, M E; Kramer, B E; Roeder, A D; Carey, J C; Root, S; Schinzel, A; Van Maldergem, L; Gardner, R J; Lin, R C; Seidman, C E; Seidman, J G; Wallerstein, R; Moran, E; Sutphen, R; Campbell, C E; Jorde, L B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1999 Português
Relevância na Pesquisa
370.16887%
Ulnar-mammary syndrome (UMS) is a pleiotropic disorder affecting limb, apocrine-gland, tooth, hair, and genital development. Mutations that disrupt the DNA-binding domain of the T-box gene, TBX3, have been demonstrated to cause UMS. However, the 3' terminus of the open reading frame (ORF) of TBX3 was not identified, and mutations were detected in only two families with UMS. Furthermore, no substantial homology outside the T-box was found among TBX3 and its orthologues. The subsequent cloning of new TBX3 cDNAs allowed us to complete the characterization of TBX3 and to identify alternatively transcribed TBX3 transcripts, including one that interrupts the T-box. The complete ORF of TBX3 is predicted to encode a 723-residue protein, of which 255 amino acids are encoded by newly identified exons. Comparison of other T-box genes to TBX3 indicates regions of substantial homology outside the DNA-binding domain. Novel mutations have been found in all of eight newly reported families with UMS, including five mutations downstream of the region encoding the T-box. This suggests that a domain(s) outside the T-box is highly conserved and important for the function of TBX3. We found no obvious phenotypic differences between those who have missense mutations and those who have deletions or frameshifts.