Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
1.
J Med Case Rep ; 17(1): 323, 2023 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-37501065

RESUMO

BACKGROUND: SERPINC1 is a glycoprotein that regulates blood coagulation. SERPINC1 congenital or acquired deficiencies represent a significant risk factor for thromboembolic disease. SERPINC1 acquired defects are observed in very few cases and can occur in many clinical conditions such as treatment with L-asparaginase or oral contraceptive (particularly estrogen derivatives), but these conditions are not routinely investigated. CASE PRESENTATION: A 50-year-old Caucasian woman who took gestodene 75 µg/ethinylestradiol 20 µg as oral contraceptive, was sent to our thrombophilia clinic because, on thrombophilia testing, a reduction of SERPINC1 (74%) and a slight increase in circulating D-dimer and homocysteine were found. We investigated triggers of such SERPINC1 reduction, and identified gestodene 75 µg/ethinylestradiol 20 µg use as the most likely candidate. Two months after the discontinuation of the oral contraceptive, SERPINC1 value returned to normal (92%) and D-dimer and homocysteine were normalized. CONCLUSION: Each patient has a different sensitivity to contraceptive use. Genetic (or epigenetic) regulation of anticoagulant proteins might account for a different rate of consumption of anticoagulant proteins as oral contraceptives and probably determine the susceptibility to thrombotic events.


Assuntos
Transtornos da Coagulação Sanguínea , Trombofilia , Feminino , Humanos , Pessoa de Meia-Idade , Anticoncepcionais Orais/efeitos adversos , Etinilestradiol/efeitos adversos , Anticoagulantes/efeitos adversos , Antitrombinas , Antitrombina III
2.
Infection ; 43(1): 1-11, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25110153

RESUMO

INTRODUCTION: A growing body of evidence points out that a large amount of patients with sepsis are admitted and treated in medical ward (MW). With most of the sepsis studies conducted in intensive care unit (ICU), these patients, older and with more comorbidities have received poor attention. Provided the differences between the two groups of patients, results of diagnostic and therapeutic trials from ICU should not be routinely transferred to MW, where sepsis seems to be at least as common as in ICU. METHODS: We analyzed clinical trials on novel tools for an early diagnosis of sepsis published in the last two year adopting strict research criteria. Moreover we conducted a target review of the literature on non-invasive monitoring of severe sepsis and septic shock. RESULTS AND CONCLUSIONS: The combination of innovative and non-invasive tools for sepsis rule in/out, as quick alternatives to blood cultures (gold standard) with bedside integrated ultrasonography could impact triage, diagnosis and prognosis of septic patients managed in MW, preventing ICU admissions, poor outcomes and costly complications, especially in elderly that are usually highly vulnerable to invasive procedures.


Assuntos
Sepse , Idoso , Biomarcadores , Comorbidade , Unidades Hospitalares , Humanos , Unidades de Terapia Intensiva , Pessoa de Meia-Idade
3.
Arch Gerontol Geriatr ; 49 Suppl 1: 83-94, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19836620

RESUMO

Remodeling of skeletal muscles is regulated by matrix metalloproteinases (MMPs). Functional genetic polymorphism (PM), modulating the expression of some MMPs, might be associated to different body composition and muscular strength improvement after exercise. Genetic PM of MMP-1 (G+/- at -1607), MMP-3 (5A/6A at -1171) and MMP-9 (Cytosine-Adenine microsatellite=(13-27)CA) repeats, around -90), body cell mass (BCM), extracellular water (ECW) and isometric maximal extensor strength (MES) of both legs were determined in 17 old sedentary women at the beginning and at the end of a 24 week physical exercise program. A 12 and 72% increase in BCM and MES, respectively, and 11% reduction in ECW were observed at the end of the program. Carriers of G-insertion in MMP-1, PM increased their BCM (7 kg vs. -1.5, p=0.007) and lost ECW (9% of total body water vs. 0.1%, p=0.004) more than the non-carriers; homozygote for 21 or less CA repeats/allele in MMP-9 PM gained more MES (115 N, interquartile range=IQR=63-132) than carriers of longer microsatellites (63 N, IQR=40-86, p=0.028). MMP-3 did not show any association with body composition and exercise-related strength changes. Exercise in elderly women increases BCM and strength, these changes are associate to specific MMP genotypes.


Assuntos
Envelhecimento/fisiologia , Composição Corporal/fisiologia , DNA/genética , Contração Isométrica/fisiologia , Metaloproteinases da Matriz/genética , Força Muscular/fisiologia , Polimorfismo Genético , Idoso , Teste de Esforço , Feminino , Genótipo , Humanos , Masculino , Metaloproteinase 1 da Matriz/biossíntese , Metaloproteinase 1 da Matriz/genética , Metaloproteinase 3 da Matriz/biossíntese , Metaloproteinase 3 da Matriz/genética , Metaloproteinase 9 da Matriz/biossíntese , Metaloproteinase 9 da Matriz/genética , Metaloproteinases da Matriz/biossíntese , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase
4.
Mol Microbiol ; 51(4): 1129-42, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14763985

RESUMO

In yeast the UPF1, UPF2 and UPF3 genes encode three interacting factors involved in translation termination and nonsense-mediated mRNA decay (NMD). UPF1 plays a central role in both processes. In addition, UPF1 was originally isolated as a multicopy suppressor of mitochondrial splicing deficiency, and its deletion leads to an impairment in respiratory growth. Here, we provide evidence that inactivation of UPF2 or UPF3, like that of UPF1, leads to an impairment in respiratory competence, suggesting that their products, Upf1p, Upf2p and Upf3p, are equivalently involved in mitochondrial biogenesis. In addition, however, we show that only Upf1p acts as a multicopy suppressor of mitochondrial splicing deficiency, and its activity does not require either Upf2p or Upf3p. Mutations in the conserved cysteine- and histidine-rich regions and ATPase and helicase motifs of Upf1p separate the ability of Upf1p to complement the respiratory impairment of a Deltaupf1 strain from its ability to act as a multicopy suppressor of mitochondrial splicing deficiency, indicating that distinct pathways express these phenotypes. In addition, we show that, when overexpressed, Upf1p is not detected within mitochondria, suggesting that its role as multicopy suppressor of mitochondrial splicing deficiency is indirect. Furthermore, we provide evidence that cells overexpressing certain upf1 alleles accumulate a phosphorylated isoform of Upf1p. Altogether, these results indicate that overexpression of Upf1p compensates for mitochondrial splicing deficiency independently of its role in mRNA surveillance, which relies on Upf1p-Upf2p-Upf3p functional interplay.


Assuntos
Mitocôndrias/metabolismo , RNA Helicases/genética , RNA Helicases/fisiologia , Splicing de RNA , RNA Mensageiro/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Motivos de Aminoácidos , Análise Mutacional de DNA , Inativação Gênica , Genes Fúngicos , Teste de Complementação Genética , Mutação , Consumo de Oxigênio , Terminação Traducional da Cadeia Peptídica , Fosforilação , Biossíntese de Proteínas , RNA Helicases/metabolismo , Processamento Pós-Transcricional do RNA , RNA Fúngico/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/fisiologia , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/fisiologia , Supressão Genética , Transativadores/genética , Transativadores/fisiologia
5.
Eur J Vasc Endovasc Surg ; 26(4): 374-80, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14511998

RESUMO

OBJECTIVE: To determine the fatal and non-fatal cardiovascular event rate in patients with intermittent claudication treated with antiplatelet agents. METHODS AND DESIGN: Patients with PAD-II stage Fontaine (n=223) and sex and age matched controls (n=446) were followed up from 1974 to 1998. All patients were treated with antiplatelet agents (aspirin, 325 mg once daily or ticlopidine, 250 mg twice daily) and for risk factors, if present. The end points were death for any cause (vascular event, cancer, and others) and non-fatal vascular events (myocardial infarction, ischemic/hemorrhagic stroke, and leg amputation). RESULTS: PAD patients had a significantly higher mortality rate than controls (3.99 vs. 2.53 deaths for 100 patients per year, respectively), cancer (mostly lung, stomach and colon) and vascular mortality accounted for such difference. The incidence of non-fatal vascular events was three times higher in patients than in controls (1.7 vs. 0.56, 100 patients per year, respectively, p<0.05) even considering amputation separately (0.28 vs. 0.00, 100 patients per year, p<0.05). No difference between patients treated with aspirin or ticlopidine could be found in both end points. CONCLUSIONS: Vascular mortality and morbidity, despite the use of antiplatelet agents, are still higher than sex and age matched controls; however, the commonest cause of death is cancer.


Assuntos
Claudicação Intermitente/tratamento farmacológico , Inibidores da Agregação Plaquetária/uso terapêutico , Ticlopidina/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Aspirina/uso terapêutico , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/mortalidade , Causas de Morte , Feminino , Seguimentos , Humanos , Claudicação Intermitente/complicações , Masculino , Pessoa de Meia-Idade , Prognóstico , Fatores de Risco
6.
Blood Coagul Fibrinolysis ; 13(3): 247-55, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11943939

RESUMO

The aim of the study was to evaluate which pattern of coagulation indicators characterizes unstable angina and, particularly, its relationship with short-term prognosis. Forty patients with unstable angina (UA Group) at admission in the intensive care unit, 40 patients with chronic stable effort angina (SEA Group), and 20 age- and sex-matched healthy controls were studied. Blood coagulation indicators were fibrinogen, prothrombin fragment F1 + 2 (F1 + 2), thrombus precursor protein (TpP), and D-dimer. C reactive protein (CRP) and cardiac Troponin I (cTnI) have also been determined and compared. Patients in the UA Group were followed for in-hospital adverse events (sudden death, acute myocardial infarction and angina refractory to medical therapy). CRP, D-dimer and cTnI plasma levels were significantly lower in the SEA Group than in the UA Group; the same trend was found for fibrinogen and F1 + 2 plasma levels, although not statistically significant. The TpP was similar in all groups. The control group showed the lowest levels for all indicators. Within the UA Group, 17 patients developed adverse events during hospitalization; F1 + 2, D-dimer, cTnI and CRP plasma levels were higher in these patients than in those with good outcome. Relative risks for adverse events associated with the highest tertile of D-dimer, cTnI, and CRP plasma levels were 8.4 (95% confidence interval, 1.5-48.9), 6.7 (95% confidence interval, 1.1-38.6) and 5.2 (95% confidence interval, 1.1-25.2), respectively. D-Dimer is significantly increased in patients with unstable angina and, in particular, in those who develop an adverse event.


Assuntos
Proteínas de Fase Aguda/análise , Angina Pectoris/sangue , Angina Instável/sangue , Proteínas Sanguíneas/análise , Produtos de Degradação da Fibrina e do Fibrinogênio/análise , Proteínas de Neoplasias , Troponina I/sangue , Idoso , Angina Pectoris/tratamento farmacológico , Angina Pectoris/etiologia , Angina Instável/tratamento farmacológico , Biomarcadores , Proteína C-Reativa/análise , Doença Crônica , Morte Súbita Cardíaca/epidemiologia , Feminino , Fibrinogênio/análise , Seguimentos , Humanos , Inflamação/sangue , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/epidemiologia , Fragmentos de Peptídeos/análise , Peroxidases/análise , Peroxirredoxina III , Peroxirredoxinas , Esforço Físico , Prognóstico , Isoformas de Proteínas/sangue , Protrombina/análise , Fatores de Risco , Resultado do Tratamento
7.
Am Heart J ; 140(3): 423-9, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10966540

RESUMO

The aim of this study was to determine whether paroxysmal atrial fibrillation (PAF) and/or restoration to sinus rhythm with electric or pharmacologic cardioversion induce modifications to the coagulation system. Thirty-five patients with PAF undergoing either electric (n = 11) or pharmacologic (n = 24) cardioversion were studied. Fibrinopeptide A and D-dimer blood samples were taken immediately before and after cardioversion at different intervals. When compared with the control group (n = 70), the precardioversion fibrinopeptide A plasma values were significantly elevated (11.8 vs 2.5 ng/mL). Fibrinopeptide A plasma values were significantly reduced 5 minutes after cardioversion (11.8 vs 5.3 ng/mL) and remained stable throughout the follow-up sequential measurements. D-dimer plasma values were significantly increased (measured at 12 hours and at day 7) in patients who underwent electrical cardioversions only. A positive correlation (R(2) = 0.76) was found between the energy delivered for cardioversion to sinus rhythm and D-dimer plasma values on day 7. In patients with PAF, levels of fibrinopeptide A, an indicator of coagulation activation, are elevated and soon reduced by the restoration of sinus rhythm. Electric, but not pharmacologic, cardioversion induces an early activation of the fibrinolytic system.


Assuntos
Fibrilação Atrial/complicações , Transtornos da Coagulação Sanguínea/etiologia , Cardioversão Elétrica , Idoso , Fibrilação Atrial/terapia , Transtornos da Coagulação Sanguínea/diagnóstico , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio/análise , Fibrinólise/efeitos dos fármacos , Fibrinólise/fisiologia , Fibrinopeptídeo A/análise , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
8.
Nucleic Acids Res ; 28(1): 148-52, 2000 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-10592207

RESUMO

MitBASE is an integrated and comprehensive database of mitochondrial DNA data which collects, under a single interface, databases for Plant, Vertebrate, Invertebrate, Human, Protist and Fungal mtDNA and a Pilot database on nuclear genes involved in mitochondrial biogenesis in Saccharomyces cerevisiae. MitBASE reports all available information from different organisms and from intraspecies variants and mutants. Data have been drawn from the primary databases and from the literature; value adding information has been structured, e.g., editing information on protist mtDNA genomes, pathological information for human mtDNA variants, etc. The different databases, some of which are structured using commercial packages (Microsoft Access, File Maker Pro) while others use a flat-file format, have been integrated under ORACLE. Ad hoc retrieval systems have been devised for some of the above listed databases keeping into account their peculiarities. The database is resident at the EBI and is available at the following site: http://www3.ebi.ac.uk/Research/Mitbase/mitbas e.pl. The impact of this project is intended for both basic and applied research. The study of mitochondrial genetic diseases and mitochondrial DNA intraspecies diversity are key topics in several biotechnological fields. The database has been funded within the EU Biotechnology programme.


Assuntos
DNA Mitocondrial/genética , Bases de Dados Factuais , Animais , DNA Fúngico/genética , DNA de Plantas/genética , Eucariotos/genética , Humanos , Internet , Invertebrados/genética , Plantas/genética , Vertebrados/genética
9.
Nucleic Acids Res ; 27(1): 128-33, 1999 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-9847157

RESUMO

MitBASE is an integrated and comprehensive database of mitochondrial DNA data which collects all available information from different organisms and from intraspecie variants and mutants. Research institutions from different countries are involved, each in charge of developing, collecting and annotating data for the organisms they are specialised in. The design of the actual structure of the database and its implementation in a user-friendly format are the care of the European Bioinformatics Institute. The database can be accessed on the Web at the following address: http://www.ebi.ac. uk/htbin/Mitbase/mitbase.pl. The impact of this project is intended for both basic and applied research. The study of mitochondrial genetic diseases and mitochondrial DNA intraspecie diversity are key topics in several biotechnological fields. The database has been funded within the EU Biotechnology programme.


Assuntos
DNA Mitocondrial/genética , Bases de Dados Factuais , Animais , Núcleo Celular/genética , Classificação , DNA Mitocondrial/classificação , Eucariotos/genética , Europa (Continente) , Fungos/genética , Código Genético , Doenças Genéticas Inatas/genética , Variação Genética , Humanos , Armazenamento e Recuperação da Informação , Internet , Invertebrados/genética , Mutação , Plantas/genética , Interface Usuário-Computador , Vertebrados/genética
10.
Nucleic Acids Res ; 27(1): 147-9, 1999 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-9847161

RESUMO

In the framework of the EU BIOTECH PROGRAM and within the 'MITBASE: a comprehensive and integrated database on mtDNA' project, we have prepared a pilot database (MitBASE Pilot) on nuclear genes involved in mitochondrial biogenesis and its regulation in Saccharomyces cerevisiae. MitBASE Pilot includes nuclear genes encoding mitochondrial proteins as well as nuclear genes encoding products which are localised in other sub-cellular compartments but nevertheless interact with mitochondrial functions. Genes have been classified on the basis of the mitochondrial process in which they participate and the mitochondrial phenotype of the gene knockout. The structure of the MitBASE Pilot database has been conceived for a flexible organisation of the information. An intuitive visual query system has been developed which allows users to select information in different combinations, both in the query and the output format, according to their needs. MitBASE Pilot is a relational database, is maintained at the EMBL-European Bioinformatics Institute (EBI) and is available at the World Wide Web site http://www3.ebi.ac. uk/Research/Mitbase/mitbiog.pl


Assuntos
Bases de Dados Factuais , Genes Fúngicos/genética , Mitocôndrias/fisiologia , Saccharomyces cerevisiae/genética , Núcleo Celular/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Armazenamento e Recuperação da Informação , Internet , Mitocôndrias/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento
11.
FEBS Lett ; 409(1): 96-100, 1997 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-9199511

RESUMO

The two adjacent nuclear genes ISF1 and NAM7 cooperatively participate in mitochondrial functions. It is well known that Cyp1p(Hap1p) activates a number of genes involved in these same functions. We show in this paper that Cyp1p influences the transcriptional regulation of NAM7. In addition, a significant amount of ISF1-NAM7 cotranscript is observed in a cyp1 mutant context. An extensive analysis of the intergenic region which separates the two genes revealed 5' starts of the NAM7 transcripts, additional to those previously mapped. These new 5' starts overlap the 3' ends of ISF1. We propose that NAM7 is under the control of a negative Cyp1p-dependent regulator and that its absence favours a transcriptional read-through which results in the ISF1-NAM7 cotranscript we have identified.


Assuntos
Proteínas de Ligação a DNA , Proteínas Fúngicas/genética , Genes Fúngicos , RNA Helicases , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Transativadores/genética , Transcrição Gênica , Sequência de Aminoácidos , Sequência de Bases , Proteínas Fúngicas/fisiologia , Regulação Fúngica da Expressão Gênica , Dados de Sequência Molecular , RNA Fúngico/genética , Proteínas Repressoras/genética , Transativadores/fisiologia , Fatores de Transcrição
12.
Ital J Gastroenterol Hepatol ; 29(1): 22-4, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9265574

RESUMO

BACKGROUND: Chronic diarrhea is a common feature in children infected with human immunodeficiency virus (HIV), and is associated with an increased risk of death in these patients. To describe the effects of an empiric treatment on diarrhea and body weight on HIV-infected pediatric patients. PATIENTS: Eleven vertically HIV-infected children with chronic diarrhea were treated with oral gentamicin, metronidazole and cholestyramine for 3 to 5 days. RESULTS: In children not infected by Cryptosporidium the treatment resulted in a 50% reduction of stool frequency and a 9% increase in body weight. No statistically significant effect was found in children harbouring this parasite. Diarrhea relapsed within 1-2 months in 3/3 children with Cryptosporidium and in 1/8 children without Cryptosporidium (p < 0.05). No untoward side effects from the treatment were observed. CONCLUSIONS: These results suggest that an empiric treatment of this type should be attempted early in HIV-infected children with chronic diarrhea, particularly in those not infected by Cryptosporidium.


Assuntos
Antibacterianos/administração & dosagem , Resina de Colestiramina/administração & dosagem , Diarreia/tratamento farmacológico , Gentamicinas/administração & dosagem , Enteropatia por HIV/tratamento farmacológico , Metronidazol/administração & dosagem , Criança , Pré-Escolar , Doença Crônica , Quimioterapia Combinada , Infecções por HIV/congênito , Infecções por HIV/transmissão , Humanos , Lactente , Transmissão Vertical de Doenças Infecciosas
13.
Minerva Pediatr ; 48(11): 499-502, 1996 Nov.
Artigo em Italiano | MEDLINE | ID: mdl-9064497

RESUMO

BACKGROUND: The diagnosis of cow's milk protein intolerance (CMPI) is mainly based on the response to the elimination diet and to the subsequent exposure to these proteins (challenge). METHODS: To find out whether a "formal", strictly scheduled challenge was better than a less formal test in establishing CMPI diagnosis, records were reviewed of 87 children studied in 5 Hospitals in the Milan area during the last 3 years. RESULTS: The study showed that the diagnostic approach (formal vs informal challenge) did not affect the probability of confirming CMPI diagnosis (21% vs 19%). Moreover, this probability was not affected by the source of the first diagnosis (Hospital vs Family Doctor), the time elapsed between first diagnosis and challenge, and the laboratory tests performed during the challenge. CONCLUSIONS: Therefore, a less strictly scheduled approach could be conveniently suggested to confirm CMPI diagnosis, at least in unselected cases.


Assuntos
Hipersensibilidade a Leite/diagnóstico , Proteínas do Leite/efeitos adversos , Animais , Criança , Fenômenos Fisiológicos da Nutrição Infantil , Humanos
14.
FEBS Lett ; 382(1-2): 111-5, 1996 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-8612730

RESUMO

The nuclear gene OXA1 was first isolated in Saccharomyces cerevisiae and found to be required at a post-translational step in cytochrome c oxidase biogenesis, probably at the level of assembly. Mutations in OXA1 lead to a complete respiratory deficiency. The protein Oxa1p is conserved through evolution and a human homolog has been isolated by functional complementation of a yeast oxa1- mutant. In order to further our understanding of the role of Oxa1p, we have constructed two yeast strains in which the OXA1 open reading frame was almost totally deleted. Cytochrome spectra and enzymatic activity measurements show the absence of heme aa3 and of a cytochrome c oxido-reductase activity and dramatic decrease of the oligomycin sensitive ATPase activity. Analysis of the respiratory complexes in non-denaturing gels reveals that Oxa1p is necessary for the correct assembly of the cytochrome c oxidase and the ATP synthase complex.


Assuntos
Adenosina Trifosfatases/biossíntese , Proteínas de Transporte , Complexo IV da Cadeia de Transporte de Elétrons/biossíntese , Proteínas Fúngicas/fisiologia , Proteínas de Membrana/biossíntese , Proteínas Nucleares/fisiologia , Saccharomyces cerevisiae/enzimologia , Adenosina Trifosfatases/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Proteínas Fúngicas/genética , Genes Fúngicos/fisiologia , Heme/análogos & derivados , Heme/análise , Proteínas de Membrana/metabolismo , Mitocôndrias/enzimologia , Proteínas Mitocondriais , ATPases Mitocondriais Próton-Translocadoras , Proteínas Nucleares/genética , Oligomicinas , Fases de Leitura Aberta/genética , Saccharomyces cerevisiae/genética , Deleção de Sequência , Succinato Citocromo c Oxirredutase/metabolismo
15.
Mol Biol Cell ; 6(5): 611-25, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7545033

RESUMO

In Saccharomyces cerevisiae the UPF1 protein is required for nonsense-mediated mRNA decay, the accelerated turnover of mRNAs containing a nonsense mutation. Several lines of evidence suggest that translation plays an important role in the mechanism of nonsense mRNA decay, including a previous report that nonsense mRNAs assemble in polyribosomes. In this study we show that UPF1 and ribosomal protein L1 co-localize in the cytoplasm and that UPF1 co-sediments with polyribosomes. To detect UPF1, three copies of the influenza hemagglutinin epitope were placed at the C-terminus. The tagged protein, UPF1-3EP, retains 86% (+/- 5%) of function. Using immunological detection, we found that UPF1-3EP is primarily cytoplasmic and was not detected either in the nucleus or in the mitochondrion. UPF1-3EP and L1 co-distributed with polyribosomes fractionated in a 7-47% sucrose gradient. The sucrose sedimentation profiles for UPF1-3EP and L1 exhibited similar changes using three different sets of conditions that altered the polyribosome profile. When polyribosomes were disaggregated, UPF1-3EP and L1 accumulated in fractions coincident with 80S ribosomal particles. These results suggest that UPF1-3EP associates with polyribosomes. L3 and S3 mRNAs, which code for ribosomal proteins of the 60S and 40S ribosomal subunits, respectively, were on average about 100-fold more abundant than UPF1 mRNA. Assuming that translation rates for L3, S3, and UPF1 mRNA are similar, this result suggests that there are far fewer UPF1 molecules than ribosomes per cell. Constraints imposed by the low UPF1 abundance on the functional relationships between UPF1, polyribosomes, and nonsense mRNA turnover are discussed.


Assuntos
Proteínas Fúngicas/análise , Polirribossomos/química , RNA Helicases , RNA Fúngico/metabolismo , RNA Mensageiro/metabolismo , Saccharomyces cerevisiae/metabolismo , Sequência de Bases , Fracionamento Celular , Citoplasma/química , Epitopos/análise , Proteínas Fúngicas/genética , Teste de Complementação Genética , Hemaglutininas Virais/genética , Hemaglutininas Virais/imunologia , Dados de Sequência Molecular , Proteínas Recombinantes de Fusão/análise , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Ribossômicas/análise , Proteínas Ribossômicas/genética , Ribossomos/química , Proteínas de Saccharomyces cerevisiae
16.
Mol Gen Genet ; 242(1): 49-56, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7506349

RESUMO

We previously isolated a nuclear 5.7 kb genomic fragment carrying the NAM7/UPF1 gene, which is able to suppress mitochondrial splicing deficiency when present in multiple copies. We show here that an immediately adjacent gene ISF1 (Increasing Suppression Factor) increases the efficiency of the NAM7/UPF1 suppressor activity. The ISF1 gene has been independently isolated as the MBR3 gene and comparison of the ISF1 predicted protein sequence with data libraries revealed a significant similarity with the MBR1 yeast protein. The ISF1 and NAM7 genes are transcribed in the same direction, and RNase mapping allowed the precise location of their termini within the intergenic region to be determined. The ISF1 gene is not essential for cell viability or respiratory growth. However as for many mitochondrial genes, ISF1 expression is sensitive to fermentative repression; in contrast expression of the NAM7 gene is unaffected by glucose. We propose that ISF1 could influence the NAM7/UPF1 function, possibly at the level of mRNA turnover, thus modulating the expression of nuclear genes involved in mitochondrial biogenesis.


Assuntos
Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Genes Fúngicos/genética , Genes Supressores/genética , Mitocôndrias/metabolismo , Proteínas de Saccharomyces cerevisiae , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , DNA Mitocondrial/genética , Elementos Facilitadores Genéticos , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Genes Reguladores , Glucose/metabolismo , Dados de Sequência Molecular , Mutagênese Insercional , Fases de Leitura Aberta , Poli A/metabolismo , Regiões Promotoras Genéticas , RNA/metabolismo , Splicing de RNA , RNA Fúngico/metabolismo , RNA Mensageiro/metabolismo , Proteínas Repressoras/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Alinhamento de Sequência
17.
J Mol Biol ; 224(3): 575-87, 1992 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-1314899

RESUMO

The yeast nuclear gene NAM7 was previously isolated within a genomic fragment of 7.7 kb (1 kb = 10(3) bases or base-pairs), having the ability to suppress mitochondrial intronic mutations defective in RNA splicing. We have identified and sequenced the region on the insert corresponding to the NAM7 gene. A long open reading frame has been revealed which could code for a protein of 971 amino acids. Comparison of the NAM7 putative protein with data libraries did not reveal any strong similarity with known proteins. However, the NAM7 protein contains several motifs typical for proteins interacting with nucleic acids: (1) five motifs diagnostic for a superfamily of helicases appear in the same order and with similar distances; (2) the N-terminal portion possesses potential Zn-ligand structures belonging to the C chi superfamily. Deletion of the chromosomal copy of NAM7 gene leads to a partial impairment in respiratory growth that is particularly striking at low temperature. Southern blot analysis of DNA extracted from a nam7 :: URA3 deleted strain revealed the presence of a second gene whose sequence is related to that of the NAM7 gene and which could participate in the same process.


Assuntos
DNA Helicases/genética , Genes Fúngicos , Mitocôndrias/enzimologia , Saccharomyces cerevisiae/genética , Dedos de Zinco/genética , Sequência de Aminoácidos , Sequência de Bases , Cromossomos Fúngicos , Clonagem Molecular , DNA Helicases/biossíntese , DNA Fúngico/isolamento & purificação , Transporte de Elétrons , Proteínas Fúngicas/genética , Proteínas Fúngicas/isolamento & purificação , Regulação Fúngica da Expressão Gênica , Mitocôndrias/metabolismo , Mitocôndrias/fisiologia , Dados de Sequência Molecular , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/crescimento & desenvolvimento , Transcrição Gênica
18.
Mol Gen Genet ; 215(3): 517-28, 1989 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2651895

RESUMO

We have cloned three distinct nuclear genes, NAM1, NAM7, and NAM8, which alleviate mitochondrial intron mutations of the cytochrome b and COXI (subunit I of cytochrome oxidase) genes when present on multicopy plasmids. These nuclear genes show no sequence homology to each other and are localized on different chromosomes: NAM1 on chromosome IV, NAM7 on chromosome XIII and NAM8 on chromosome VIII. Sequence analysis of the NAM1 gene shows that it encodes a protein of 440 amino acids with a typical presequence that would target the protein to the mitochondrial matrix. Inactivation of the NAM1 gene by gene transplacement leads to a dramatic reduction of the overall synthesis of mitochondrial protein, and a complete absence of the COXI protein which is the result of a specific block in COXI pre-mRNA splicing. The possible mechanisms by which the NAM1 gene product may function are discussed.


Assuntos
Genes Fúngicos , Saccharomyces cerevisiae/genética , Sequência de Aminoácidos , Sequência de Bases , Núcleo Celular/metabolismo , DNA Fúngico/genética , Proteínas Fúngicas/biossíntese , Proteínas Fúngicas/genética , Mitocôndrias/metabolismo , Dados de Sequência Molecular , Splicing de RNA , RNA Fúngico/metabolismo , RNA Mensageiro/metabolismo , Mapeamento por Restrição , Saccharomyces cerevisiae/metabolismo , Homologia de Sequência do Ácido Nucleico , Supressão Genética , Transcrição Gênica
19.
Arch Biochem Biophys ; 260(1): 94-101, 1988 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-3422549

RESUMO

The specific activity of D-3-hydroxybutyrate dehydrogenase is reduced by about a third in liver and heart mitochondria of hyperthyroid rats. State 3 respiration is also reduced in isolated mitochondria from the same animals when DL-3-hydroxybutyrate is the substrate. Determination of the kinetic parameters of the membrane-bound D-3-hydroxybutyrate dehydrogenase in liver of hyperthyroid rats reveals a decreased in maximal velocity (Vmax). The Michaelis and dissociation constants of NAD+ and D-3-hydroxybutyrate are also significantly influenced, thus indicating that both the affinity and the binding of this enzyme toward its substrates are affected. In hyperthyroid rats a significant ketone-body increase is found in both liver and heart: in blood, an almost doubled concentration can be measured. At the same time, in heart mitochondria of these animals the activity of succinyl-coenzyme A: 3-oxoacid coenzyme A-transferase is significantly reduced. The decrease in both D-3-hydroxybutyrate dehydrogenase and 3-oxoacid coenzyme A-transferase associated with the increase in ketone bodies supports the suggestion that there is a lower utilization of these compounds by peripheral tissues. In the blood of hyperthyroid rats a higher D-3-hydroxybutyrate/acteoacetate ratio is also found, probably resulting from a selective utilization of the two compounds in this pathological state.


Assuntos
Acil Coenzima A/metabolismo , Aciltransferases/metabolismo , Hidroxibutirato Desidrogenase/metabolismo , Hipertireoidismo/enzimologia , Corpos Cetônicos/metabolismo , Mitocôndrias Cardíacas/enzimologia , Mitocôndrias Hepáticas/enzimologia , Animais , Coenzima A-Transferases , Glicerolfosfato Desidrogenase/metabolismo , Hidroxibutirato Desidrogenase/antagonistas & inibidores , Cinética , Masculino , Ratos , Ratos Endogâmicos , Partículas Submitocôndricas/enzimologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...