RESUMO
OBJECTIVES: The aim of this study was to evaluate the efficacy and safety of left gastric artery (LGA) embolization for the treatment of overweight patients who weren't candidates for bariatric surgery. MATERIALS AND METHODS: We retrospectively collected data of 16 patients who underwent a selective embolization of the LGA. The mean body mass index (BMI) before intervention was 28.9 kg/m2 ± 2.5, and therefore, patients were not candidates for bariatric surgery in Belgium. The embolization was realized with 500-700 µm particles via the right common femoral artery approach. Before and following the intervention, an upper endoscopy was performed. Patient demographics, weight loss, hunger sensation and a satisfactory scale were reviewed. RESULTS: Between February 2015 and May 2017, 16 overweight patients were treated, one embolization was unsuccessful. Four (25%) patients were lost in follow-up. Nine (56%) patients showed early weight loss, one (6%) maintained his bodyweight and one (6%) patient underwent bariatric surgery 2 years after consultation. Only one (6%) patient had a gastric ulceration on control endoscopy. One (6%) patient ended in the intensive care unit for pancreatitis and gastric perforation. The mean weight loss was 8 kg ± 5.12, reducing their mean BMI to 25.5 ± 3.5. The hunger sensation was decreased, and patients were satisfied. CONCLUSION: This is a preliminary study in an overweight population that appears to induce weight loss and appetite suppression. Larger studies are needed to confirm these preliminary findings.
Assuntos
Embolização Terapêutica/métodos , Artéria Gástrica/diagnóstico por imagem , Sobrepeso/terapia , Adolescente , Adulto , Angiografia Digital/métodos , Bélgica , Índice de Massa Corporal , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos , Resultado do Tratamento , Redução de Peso , Adulto JovemAssuntos
Angiografia , Cateteres de Demora , Meios de Contraste/administração & dosagem , Migração de Corpo Estranho/terapia , Doença de Hodgkin/tratamento farmacológico , Falha de Equipamento , Feminino , Migração de Corpo Estranho/diagnóstico por imagem , Humanos , Veias Jugulares/diagnóstico por imagem , Pessoa de Meia-Idade , Remissão Espontânea , Veia Subclávia/diagnóstico por imagem , Parede Torácica/irrigação sanguínea , Veia Cava Superior/diagnóstico por imagemRESUMO
The Shwachman-Bodian-Diamond syndrome (SBDS) protein family occurs widely in nature, although its function has not been determined. Comprehensive database searches revealed SBDS homologues from 159 species, including examples from all sequenced archaeal and eukaryotic genomes and all eukaryotic kingdoms. Sequence alignment with ClustalX and MUSCLE algorithms led to the identification of conserved residues that occurred predominantly in the amino-terminal FYSH domain where they appeared to contribute to protein folding or stability. Only SBDS residue Gly91 was invariant in all species. Four distantly related protists were found to have two divergent SBDS genes in their genomes. In each case, phylogenetic analyses and the identification of shared sequence features suggested that one gene was derived from lateral gene transfer. We also identified a shared C-terminal zinc finger domain fusion in flowering plants and chromalveolates that may shed light on the function of the protein family and the evolutionary histories of these kingdoms. To assess the extent of SBDS functional conservation, we carried out complementation studies of SBDS homologues and interspecies chimeras in Saccharomyces cerevisiae. We determined that the FYSH domain was widely interchangeable among eukaryotes, while domain 2 imparted species specificity to protein function. Domain 3 was largely dispensable for function in our yeast complementation assay. Overall, the phylogeny of SBDS was shared with a group of proteins that were markedly enriched for RNA metabolism and/or ribosome-associated functions. These findings link Shwachman-Diamond syndrome to other bone marrow failure syndromes with defects in nucleolus-associated processes, including Diamond-Blackfan anemia, cartilage-hair hypoplasia, and dyskeratosis congenita.
Assuntos
Proteínas/genética , Sequência de Aminoácidos , Animais , Doenças da Medula Óssea/genética , Sequência Conservada , Transferência Genética Horizontal , Teste de Complementação Genética , Humanos , Modelos Genéticos , Dados de Sequência Molecular , Filogenia , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Estrutura Terciária de Proteína , Proteínas/química , Homologia de Sequência de Aminoácidos , Especificidade da Espécie , Síndrome , Dedos de ZincoRESUMO
Pancreatic exocrine and bone marrow dysfunctions are considered to be universal features of Shwachman-Diamond syndrome (SDS) whereas the associated skeletal dysplasia is variable and not consistently observed. The genetic defect in SDS has recently been identified; causative mutations have been shown in the SBDS gene. The aims of this study were to characterize the nature, frequency, and age-related changes of radiographic skeletal abnormalities in patients with SBDS mutations and to assess genotype-phenotype correlation. Fifteen patients (mean age 9.7 years) with a clinical diagnosis of SDS and documented SBDS gene mutations were included. Review of their skeletal radiographs showed abnormalities in all patients. The skeletal changes were variable, even in patients with identical genotypes. The typical features were (1) delayed appearance of secondary ossification centers, (2) variable widening and irregularity of the metaphyses in early childhood, followed by progressive thickening and irregularity of the growth plates, and (3) generalized osteopenia. There was a tendency towards normalization of the epiphyseal maturation defect and progression of the metaphyseal changes with age. The results suggest that the characteristic skeletal changes are present in all patients with SDS and SBDS mutations, but their severity and localization varies with age. No phenotype-genotype correlation was observed.
Assuntos
Medula Óssea/fisiopatologia , Mutação , Osteocondrodisplasias/genética , Pâncreas/fisiopatologia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Osteocondrodisplasias/diagnóstico por imagem , Osteocondrodisplasias/fisiopatologia , Fenótipo , Radiografia , SíndromeRESUMO
OBJECTIVE: To evaluate the supraspinatus muscle radiodensity on the outlet view as an indication of a tendon tear. DESIGN AND PATIENTS: Plain radiographs and magnetic resonance imaging (MRI) examinations were obtained on both shoulders of 40 subjects aged 23-70 years, including 13 asymptomatic volunteers and 27 patients. Two readers analyzed the superior contour and the heterogeneity of the supraspinatus muscle radiodensity and compared them with the MRI findings. RESULTS AND CONCLUSION: Significant concordances (P < 0.001) were found between the assessments of the superior contour and the heterogeneity of the muscle radiodensity, respectively, on plain radiographs and MR images. For the diagnosis of a full-thickness tear, the analysis of the superior contour and the heterogeneity of the muscle radiodensity reached an accuracy of 85% and 80% respectively. Stepwise discriminant analyses showed low to moderate benefit of considering the contour and the heterogeneity simultaneously. The inter- and intraobserver agreement ranged from moderate to good. We conclude that on the outlet view, modifications in the superior contour and heterogeneity of the supraspinatus muscle radiodensity suggest a full-thickness tear.
Assuntos
Músculo Esquelético/diagnóstico por imagem , Lesões do Manguito Rotador , Ombro/diagnóstico por imagem , Adulto , Idoso , Artroscopia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/patologia , Variações Dependentes do Observador , Valor Preditivo dos Testes , Radiografia , Manguito Rotador/diagnóstico por imagem , Manguito Rotador/patologia , Sensibilidade e Especificidade , Ombro/patologiaRESUMO
Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterized by exocrine pancreatic insufficiency and hematologic and skeletal abnormalities. A genomewide scan of families with SDS was terminated at approximately 50% completion, with the identification of chromosome 7 markers that showed linkage with the disease. Finer mapping revealed significant linkage across a broad interval that included the centromere. The maximum two-point LOD score was 8.7, with D7S473, at a recombination fraction of 0. The maximum multipoint LOD score was 10, in the interval between D7S499 and D7S482 (5.4 cM on the female map and 0 cM on the male map), a region delimited by recombinant events detected in affected children. Evidence from all 15 of the multiplex families analyzed provided support for the linkage, consistent with a single locus for SDS. However, the presence of several different mutations is suggested by the heterogeneity of disease-associated haplotypes in the candidate region.
Assuntos
Doenças da Medula Óssea/genética , Centrômero/genética , Cromossomos Humanos Par 7/genética , Insuficiência Pancreática Exócrina/genética , Ligação Genética/genética , Alelos , Doenças da Medula Óssea/sangue , Doenças da Medula Óssea/patologia , Mapeamento Cromossômico , Insuficiência Pancreática Exócrina/patologia , Feminino , Frequência do Gene , Genes Recessivos/genética , Heterogeneidade Genética , Haplótipos/genética , Humanos , Escore Lod , Masculino , Modelos Genéticos , Anormalidades Musculoesqueléticas/genética , Anormalidades Musculoesqueléticas/patologia , Mutação/genética , Células Mieloides/patologia , Linhagem , Software , SíndromeRESUMO
It is difficult to identify genes that predispose to prostate cancer due to late age at diagnosis, presence of phenocopies within high-risk pedigrees and genetic complexity. A genome-wide scan of large, high-risk pedigrees from Utah has provided evidence for linkage to a locus on chromosome 17p. We carried out positional cloning and mutation screening within the refined interval, identifying a gene, ELAC2, harboring mutations (including a frameshift and a nonconservative missense change) that segregate with prostate cancer in two pedigrees. In addition, two common missense variants in the gene are associated with the occurrence of prostate cancer. ELAC2 is a member of an uncharacterized gene family predicted to encode a metal-dependent hydrolase domain that is conserved among eukaryotes, archaebacteria and eubacteria. The gene product bears amino acid sequence similarity to two better understood protein families, namely the PSO2 (SNM1) DNA interstrand crosslink repair proteins and the 73-kD subunit of mRNA 3' end cleavage and polyadenylation specificity factor (CPSF73).
Assuntos
Cromossomos Humanos Par 17/genética , Proteínas de Neoplasias/genética , Neoplasias da Próstata/genética , Sequência de Aminoácidos , Clonagem Molecular/métodos , DNA Complementar/genética , Efeito Fundador , Ligação Genética , Predisposição Genética para Doença , Genótipo , Humanos , Masculino , Dados de Sequência Molecular , Mutação de Sentido Incorreto , Linhagem , RNA Mensageiro/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , UtahRESUMO
It has been previously determined that ClC-2, a member of the ClC chloride channel superfamily, is expressed in certain epithelial tissues. These findings fueled speculation that ClC-2 can compensate for impaired chloride transport in epithelial tissues affected by cystic fibrosis and lacking the cystic fibrosis transmembrane conductance regulator. However, direct evidence linking ClC-2 channel expression to epithelial chloride secretion was lacking. In the present studies, we show that ClC-2 transcripts and protein are present endogenously in the Caco-2 cell line, a cell line that models the human small intestine. Using an antisense strategy we show that ClC-2 contributes to native chloride currents in Caco-2 cells measured by patch clamp electrophysiology. Antisense ClC-2-transfected monolayers of Caco-2 cells exhibited less chloride secretion (monitored as iodide efflux) than did mock transfected monolayers, providing the first direct molecular evidence that ClC-2 can contribute to chloride secretion by the human intestinal epithelium. Further, examination of ClC-2 localization by confocal microscopy revealed that ClC-2 contributes to secretion from a unique location in this epithelium, from the apical aspect of the tight junction complex. Hence, these studies provide the necessary rationale for considering ClC-2 as a possible therapeutic target for diseases affecting intestinal chloride secretion such as cystic fibrosis.
Assuntos
Canais de Cloreto/fisiologia , Cloretos/metabolismo , Células CACO-2 , Membrana Celular/química , Polaridade Celular , Canais de Cloreto/análise , Canais de Cloreto/genética , Humanos , Técnicas de Patch-Clamp , Junções Íntimas/fisiologiaRESUMO
While most cystic fibrosis (CF) transmembrane conductance regulator (CFTR)-knockout animals die due to intestinal obstruction before or at the time of weaning, a subpopulation of these animals are long living and exhibit a milder phenotype. The decreased severity of intestinal disease in these mildly affected CF mice is related to the expression of non-CFTR genetic modifiers. The identity of these genetic modifiers is not known, but we hypothesize that they may complement CFTR function as a chloride channel in this tissue. To assess the contribution of non-CFTR chloride channels to chloride secretion across the small intestine of CF mice with mild disease, we measured the basal transepithelial potential difference across this tissue as well as the secretory response to agonists of the cAMP and the calcium-mediated signaling pathways. Chloride secretion across the small intestine of mildly affected CF mice was not stimulated by forskolin or by carbachol. The absence of CFTR is thus not compensated by the activity of a distinct, cAMP- or calcium-activated chloride channel at the apical surface of the intestinal epithelium. On the other hand, a basal chloride secretion across the intestinal epithelium was present in these animals, and we hypothesize that this activity may be linked to improved survival of these animals.
Assuntos
Canais de Cloreto/metabolismo , Cloretos/metabolismo , Fibrose Cística/metabolismo , Íleo/metabolismo , Inibidores da Angiogênese/farmacologia , Animais , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/fisiologia , Canais de Cloro CLC-2 , Sinalização do Cálcio/fisiologia , Canais de Cloreto/genética , Colforsina/farmacologia , AMP Cíclico/metabolismo , Fibrose Cística/patologia , Expressão Gênica/fisiologia , Íleo/patologia , Camundongos , Camundongos Endogâmicos CFTR , Nitrobenzoatos/farmacologia , RNA Mensageiro/análiseRESUMO
Loop-tail (Lp) is a semidominant mutation that maps to the distal portion of mouse Chromosome (Chr) 1 and is an established model for neural tube defects (NTDs). Homozygous embryos exhibit an open neural tube from the caudal midbrain to the tip of the tail that results from over-differentiation of the floor plate. To facilitate the positional cloning of the Lp gene, both cDNA selection and assignment of sequence-tagged-sites from the human transcript map have been used to identify genes within the Lp interval. Together with previous physical mapping, this has allowed the placement of 13 transcription units within an approximately 1-Mb region that spans the Lp genetic interval, and eight of these genes map to the nonrecombinant interval. This map includes genes that encode proteins involved in protein sorting and targeting (Tim23 and Copa), ion transport (Atp1a2, Atp1a4, and Girk3), transcription (Nhlh1), immune regulation (Cd48 and Fcer1alpha), cell adhesion (R88252), apoptosis (Pea15), and several of unknown function (H326, Kiaa0253, and Estm34). Expression analysis by Northern blotting indicated that a subset of these genes are expressed preferentially in the developing nervous system. Finally, this region of mouse Chr 1 represents a conserved linkage group with genes on human chromosome 1q21, a region that is frequently altered in human cancers and that harbors loci for several genetic conditions. Consequently, analysis of the Lp interval may provide important tools to understand how the corresponding region of human Chr 1 contributes to disease, in addition to defining a key gene product required for neurulation.
Assuntos
Mapeamento Cromossômico , Defeitos do Tubo Neural/genética , Animais , Northern Blotting , Modelos Animais de Doenças , Embrião de Mamíferos/metabolismo , Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Masculino , Camundongos , Mutação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Distribuição Tecidual , Transcrição GênicaRESUMO
Programmed cell death or apoptosis leads to the activation of the caspase-activated DNase (CAD), which degrades chromosomal DNA into nucleosomal fragments. Biochemical studies revealed that CAD forms an inactive heterodimer with the inhibitor of caspase-activated DNase (ICAD), or its alternatively spliced variant, ICAD-S, in the cytoplasm. It was initially proposed that proteolytic cleavage of ICAD by activated caspases causes the dissociation of the ICAD/CAD heterodimer and the translocation of active CAD into the nucleus in apoptotic cells. Here, we show that endogenous and heterologously expressed ICAD and CAD reside predominantly in the nucleus in nonapoptotic cells. Deletional mutagenesis and GFP fusion proteins identified a bipartite nuclear localization signal (NLS) in ICAD and verified the function of the NLS in CAD. The two NLSs have an additive effect on the nuclear targeting of the CAD-ICAD complex, whereas ICAD-S, lacking its NLS, appears to have a modulatory role in the nuclear localization of CAD. Staurosporine-induced apoptosis evoked the proteolysis and disappearance of endogenous and exogenous ICAD from the nuclei of HeLa cells, as monitored by immunoblotting and immunofluorescence microscopy. Similar phenomenon was observed in the caspase-3-deficient MCF7 cells upon expressing procaspase-3 transiently. We conclude that a complex mechanism, involving the recognition of the NLSs of both ICAD and CAD, accounts for the constitutive accumulation of CAD/ICAD in the nucleus, where caspase-3-dependent regulation of CAD activity takes place.
Assuntos
Apoptose/fisiologia , Núcleo Celular/metabolismo , Fragmentação do DNA/fisiologia , Desoxirribonucleases/metabolismo , Proteínas/metabolismo , Proteínas Reguladoras de Apoptose , Caspase 3 , Caspases/metabolismo , Compartimento Celular/fisiologia , Dimerização , Transdução de Sinais/fisiologia , Células Tumorais CultivadasRESUMO
Inefficient delivery of the cystic fibrosis transmembrane conductance regulator (CFTR) to the surface of cells contributes to disease in the majority of cystic fibrosis patients. Analysis of cystic fibrosis-associated missense mutations in the first nucleotide binding domain (NBD1), including A455E, S549R, Y563N, and P574H, revealed reduced levels of mature CFTR with elevated levels of carboxyl-terminal polypeptide fragments of 105 and 90 kDa. These fragments appear early in biogenesis and degrade rapidly in four distinct cell types tested including the bronchial epithelial IB3-1 cell line. They were detected at highest levels with CFTRA455E where the 105-kDa fragment accounted for 40% of newly synthesized polypeptide but for only 20 and 7% of nascent wild type and mutant DeltaF508 proteins, respectively. The bands represent core- and unglycosylated forms of the same CFTR fragment supporting that precursor forms are correctly inserted into the membrane of the endoplasmic reticulum. Proteolytic cleavage would be predicted to occur on the cytosolic face of the endoplasmic reticulum within the NBD1-R domain segment, but pharmacological testing did not support involvement of the 26 S proteasome. The examined missense mutations in NBD1 manifest differently than the major mutant, DeltaF508, and highlight a critical conformational aspect of biogenesis of CFTR.
Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/química , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Fibrose Cística/genética , Mutação , Animais , Células CHO , Células COS , Linhagem Celular , Cricetinae , Regulador de Condutância Transmembrana em Fibrose Cística/biossíntese , Células Epiteliais/metabolismo , Epitopos/metabolismo , Técnica Indireta de Fluorescência para Anticorpo , Glicosilação , Humanos , Immunoblotting , Mutação de Sentido Incorreto , Testes de Precipitina , Estrutura Terciária de Proteína , Fatores de Tempo , TransfecçãoRESUMO
OBJECTIVES: With the use of clinical data from a large international cohort, we evaluated and compared affected siblings and isolated cases. STUDY DESIGN: Data from 116 families were collected, and patients conforming to our predetermined diagnostic criteria were analyzed. Phenotypic manifestations of affected siblings and singletons were compared with the use of t tests, Wilcoxon scores, and chi2 analysis. RESULTS: Eighty-eight patients (33 female, 55 male; median age 5.20 years) fulfilled our predetermined diagnostic criteria for Shwachman syndrome; 63 patients were isolated cases, and 25 affected siblings were from 12 multiplex families. Steatorrhea was present in 86% (57 of 66), and 91% (78 of 86) displayed a low serum trypsinogen concentration. Patients older than 4 years more often had pancreatic sufficiency. Neutropenia occurred in 98%, anemia in 42%, and thrombocytopenia in 34%. Myelodysplasia or cytogenetic abnormalities were reported in 7 patients. Short stature with normal nutritional status was a prominent feature. CONCLUSIONS: Clinical features among patients with Shwachman syndrome varied between patients and with age. Similarities in phenotype between isolated cases and affected sibling sets support the hypothesis that Shwachman syndrome is a single disease entity.
Assuntos
Insuficiência Pancreática Exócrina/genética , Doenças Hematológicas/genética , Fenótipo , Infecções Bacterianas/epidemiologia , Doenças do Desenvolvimento Ósseo/epidemiologia , Doenças do Desenvolvimento Ósseo/genética , Doença Celíaca/epidemiologia , Doença Celíaca/genética , Criança , Pré-Escolar , Estudos de Coortes , Insuficiência Pancreática Exócrina/epidemiologia , Feminino , Transtornos do Crescimento/epidemiologia , Transtornos do Crescimento/genética , Doenças Hematológicas/epidemiologia , Hepatomegalia/epidemiologia , Hepatomegalia/genética , Humanos , Lactente , Recém-Nascido , Masculino , Neutropenia/epidemiologia , Neutropenia/genética , Núcleo Familiar , Estatísticas não Paramétricas , Síndrome , Tripsinogênio/sangueRESUMO
Cytoplasmic dynein is a large multisubunit microtubule-based motor protein, which mediates movement of numerous intracellular organelles. We report here the identification of the human homologue of cytoplasmic dynein intermediate chain 1 gene (DNCI1) located on human chromosome 7q21.3-q22.1. The mouse orthologue (Dnci1) was identified along with another highly related gene, Dnci2, and their RNA in situ expression patterns were examined during mouse embryogenesis. Dnci1 was found to have a highly restricted expression domain in the developing forebrain as well as the peripheral nervous system (PNS), while Dnci2 displayed a broad expression profile throughout the entire central nervous system and most of the PNS. A dynamic expression profile was also found for Dnci2 in the developing mouse limb bud. The data presented here provide a framework for the further analysis of the functional role of Dnci1 and Dnci2 in mouse and DNCI1 in human.
Assuntos
Dineínas/genética , Dineínas/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , Cromossomos Artificiais de Levedura , Dineínas/fisiologia , Embrião de Mamíferos/metabolismo , Desenvolvimento Embrionário e Fetal , Humanos , Hibridização In Situ , Botões de Extremidades/metabolismo , Camundongos , Modelos Genéticos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de Aminoácidos , Fatores de Tempo , Distribuição TecidualRESUMO
Missense substitutions in the presenilin 1 (PS1) and presenilin 2 (PS2) proteins are associated with early-onset familial Alzheimer's disease. We have used yeast-two-hybrid and coimmunoprecipitation methods to show that the large cytoplasmic loop domains of PS1 and PS2 interact specifically with three members of the armadillo protein family, including beta-catenin, p0071, and a novel neuronal-specific armadillo protein--neural plakophilin-related armadillo protein (NPRAP). The PS1:NPRAP interaction occurs between the arm repeats of NPRAP and residues 372-399 at the C-terminal end of the large cytoplasmic loop of PS1. The latter residues contain a single arm-like domain and are highly conserved in the presenilins, suggesting that they form a functional armadillo protein binding site for the presenilins.
Assuntos
Proteínas do Citoesqueleto/metabolismo , Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Transativadores , Doença de Alzheimer/genética , Sequência de Aminoácidos , Animais , Proteínas do Domínio Armadillo , Cateninas , Moléculas de Adesão Celular , Células Cultivadas , Cromatografia de Afinidade , Humanos , Imuno-Histoquímica , Proteínas de Membrana/genética , Camundongos , Microscopia Confocal , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/genética , Fosfoproteínas , Placofilinas , Testes de Precipitina , Presenilina-1 , Presenilina-2 , Ligação Proteica , Transfecção , beta Catenina , delta CateninaRESUMO
We report here the molecular cloning of an approximately 1-Mb region of recurrent amplification at 20q13.2 in breast cancer and other tumors and the delineation of a 260-kb common region of amplification. Analysis of the 1-Mb region produced evidence for five genes, ZNF217, ZNF218, and NABC1, PIC1L (PIC1-like), CYP24, and a pseudogene CRP (Cyclophillin Related Pseudogene). ZNF217 and NABC1 emerged as strong candidate oncogenes and were characterized in detail. NABC1 is predicted to encode a 585-aa protein of unknown function and is overexpressed in most but not all breast cancer cell lines in which it was amplified. ZNF217 is centrally located in the 260-kb common region of amplification, transcribed in multiple normal tissues, and overexpressed in all cell lines and tumors in which it is amplified and in two in which it is not. ZNF217 is predicted to encode alternately spliced, Kruppel-like transcription factors of 1,062 and 1,108 aa, each having a DNA-binding domain (eight C2H2 zinc fingers) and a proline-rich transcription activation domain.
Assuntos
Neoplasias da Mama/genética , Cromossomos Humanos Par 20 , Amplificação de Genes , Proteínas de Neoplasias/genética , Transativadores/genética , Sequência de Aminoácidos , Sequência de Bases , Linhagem Celular , Cromossomos Artificiais de Levedura , Clonagem Molecular , Primers do DNA , Éxons , Humanos , Hibridização in Situ Fluorescente , Íntrons , Dados de Sequência Molecular , Proteínas de Neoplasias/química , Transativadores/química , Transcrição Gênica , Células Tumorais Cultivadas , Dedos de Zinco/genéticaRESUMO
Methionine synthase catalyzes the remethylation of homocysteine to methionine via a reaction in which methylcobalamin serves as an intermediate methyl carrier. Over time, the cob(I)alamin cofactor of methionine synthase becomes oxidized to cob(II)alamin rendering the enzyme inactive. Regeneration of functional enzyme requires reductive methylation via a reaction in which S-adenosylmethionine is utilized as a methyl donor. Patients of the cblE complementation group of disorders of folate/cobalamin metabolism who are defective in reductive activation of methionine synthase exhibit megaloblastic anemia, developmental delay, hyperhomocysteinemia, and hypomethioninemia. Using consensus sequences to predicted binding sites for FMN, FAD, and NADPH, we have cloned a cDNA corresponding to the "methionine synthase reductase" reducing system required for maintenance of the methionine synthase in a functional state. The gene MTRR has been localized to chromosome 5p15.2-15.3. A predominant mRNA of 3.6 kb is detected by Northern blot analysis. The deduced protein is a novel member of the FNR family of electron transferases, containing 698 amino acids with a predicted molecular mass of 77,700. It shares 38% identity with human cytochrome P450 reductase and 43% with the C. elegans putative methionine synthase reductase. The authenticity of the cDNA sequence was confirmed by identification of mutations in cblE patients, including a 4-bp frameshift in two affected siblings and a 3-bp deletion in a third patient. The cloning of the cDNA will permit the diagnostic characterization of cblE patients and investigation of the potential role of polymorphisms of this enzyme as a risk factor in hyperhomocysteinemia-linked vascular disease.
Assuntos
5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/metabolismo , Cromossomos Humanos Par 5 , Ferredoxina-NADP Redutase/genética , Flavoproteínas/genética , Homocistinúria/genética , Sequência de Aminoácidos , Sequência de Bases , Mapeamento Cromossômico , Clonagem Molecular , DNA Complementar/genética , Ativação Enzimática , Teste de Complementação Genética , Homocistinúria/enzimologia , Humanos , Células Híbridas , Masculino , Dados de Sequência Molecular , Análise de Sequência de DNA , Homologia de Sequência de AminoácidosRESUMO
Permeability of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel to polyatomic anions of known dimensions was studied in stably transfected Chinese hamster ovary cells by using the patch clamp technique. Biionic reversal potentials measured with external polyatomic anions gave the permeability ratio (P/P) sequence NO > Cl > HCO > formate > acetate. The same selectivity sequence but somewhat higher permeability ratios were obtained when anions were tested from the cytoplasmic side. Pyruvate, propanoate, methane sulfonate, ethane sulfonate, and gluconate were not measurably permeant (P/P < 0.06) from either side of the membrane. The relationship between permeability ratios from the outside and ionic diameters suggests a minimum functional pore diameter of approximately 5.3 A. Permeability ratios also followed a lyotropic sequence, suggesting that permeability is dependent on ionic hydration energies. Site-directed mutagenesis of two adjacent threonines in TM6 to smaller, less polar alanines led to a significant (24%) increase in single channel conductance and elevated permeability to several large anions, suggesting that these residues do not strongly bind permeating anions, but may contribute to the narrowest part of the pore.
Assuntos
Ânions/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Sequência de Aminoácidos , Animais , Células CHO , Cricetinae , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulação da Expressão Gênica , Ativação do Canal Iônico/genética , Ativação do Canal Iônico/fisiologia , Potenciais da Membrana/fisiologia , Dados de Sequência Molecular , Mutagênese , Técnicas de Patch-Clamp , PermeabilidadeRESUMO
Saethre-Chotzen syndrome, a common autosomal dominant craniosynostosis in humans, is characterized by brachydactyly, soft tissue syndactyly and facial dysmorphism including ptosis, facial asymmetry, and prominent ear crura. Previously, we identified a yeast artificial chromosome that encompassed the breakpoint of an apparently balanced t(6;7) (q16.2;p15.3) translocation associated with a mild form of Saethre-Chotzen syndrome. We now describe, at the DNA sequence level, the region on chromosome 7 affected by this translocation event. The rearrangement occurred approximately 5 kb 3' of the human TWIST locus and deleted 518 bp of chromosome 7. The TWIST gene codes for a transcription factor containing a basic helix-loop-helix (b-HLH) motif and has recently been described as a candidate gene for Saethre-Chotzen syndrome, based on the detection of mutations within the coding region. Potential exon sequences flanking the chromosome 7 translocation breakpoint did not hit known genes in database searches. The chromosome rearrangement downstream of TWIST is compatible with the notion that this is a Saethre-Chotzen syndrome gene and implies loss of function of one allele by a positional effect as a possible mechanism of mutation to evoke the syndrome.
Assuntos
Acrocefalossindactilia/genética , Proteínas Nucleares , Fatores de Transcrição/genética , Translocação Genética , Sequência de Bases , Quebra Cromossômica , Mapeamento Cromossômico , Cromossomos Humanos Par 7 , Cosmídeos/genética , DNA Complementar , Genoma Humano , Humanos , Masculino , Dados de Sequência Molecular , Mutação , Análise de Sequência de DNA , Deleção de Sequência , Transcrição Gênica , Proteína 1 Relacionada a TwistRESUMO
Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is an autosomal dominant condition consisting of congenital dysplasia of the eyelids with a reduced horizontal diameter of the palpebral fissures, droopy eyelids and epicanthus inversus. Two clinical entities have been described: type I and type II. The former is distinguished by female infertility, whereas the latter presents without other symptoms. Both type I and type II were recently mapped on the long arm of chromosome 3 (3q22-q23), suggesting a common gene may be affected. The centromeric and the telomeric limits of this region are well defined between loci D3S1316 and D3S1615, which reside approximately 5 cM apart. Here, we present the construction of a YAC contig spanning the entire BPES locus using 17 polymorphic markers, 2 STS and 28 ESTs. This region of approximately 5 Mb was covered by 31 YACs, and was supported by detailed FISH analysis. In addition, we have precisely mapped the propionyl-CoA carboxylase beta polypeptide (PCCB), the gene mutated in propionic acidemia, within this contig. Apart from providing a framework for the identification of the BPES gene, this contig will also be useful for the future identification of defects and genes mapped to this region, and for developing template resources for genomic sequencing.