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1.
Emergencias (Sant Vicenç dels Horts) ; 31(4): 227-233, ago. 2019. graf, tab
Artigo em Espanhol | IBECS | ID: ibc-182762

RESUMO

Objetivos: Este estudio analiza el control del ritmo en los servicios de urgencias (SUH) y sus resultados en pacientes con fibrilación auricular (FA) de reciente comienzo, para identificar áreas de mejora en el manejo. Método: Estudio multicéntrico, observacional, prospectivo y transversal desarrollado en 124 SUH representativos del sistema sanitario español basado en el registro HERMES-AF (estrategias de manejo en el servicio de urgencias hospitalario de la FA) del 23 de mayo al 5 de junio de 2011. Se incluyeron pacientes con FA sintomática con menos de 48 h de evolución en los cuales se tomó la decisión de restaurar el ritmo sinusal. Resultados: Se incluyeron 337 pacientes, se optó por cardioversión farmacológica en 311 pacientes (92,3%), y por cardioversión eléctrica en 52 (15%), la mitad de los casos tras fracaso de los fármacos. Se obtuvo ritmo sinusal (RS) en 278 pacientes (82,5%) y el alivio de los síntomas en 297 (94%), con una tasa de efectos adversos del 0,9%, ninguno grave. Amiodarona se asoció de manera independiente a una menor tasa de RS al alta (OR = 0,442; IC 95% 0,238-0,823; p = 0,01), al contrario que la cardioversión eléctrica (OR = 4,0; IC 95% 1,2-13,3; p = 0,024). Los fármacos I-C se asociaron con una mayor proporción de altas en < 6 h (OR 2,6; IC 95% 1,6-4,3; p < 0,001) y amiodarona con más estancias prolongadas de > 24 h (OR 2,7, IC 95% 1,5-4,8; p < 0,003). Conclusiones: En los SUH, la restauración del RS en la FA de reciente comienzo es segura, efectiva y asocia beneficios clínicos para los pacientes. Reemplazar amiodarona por técnicas más efectivas y rápidas como la cardioversión eléctrica o los fármacos I-C es un área de mejora de la calidad asistencial


Objectives: To analyze heart rate control in hospital emergency departments and outcomes in patients with recent onset atrial fibrillation (AF) so that targets for improvement can be identified. Methods: Multicenter, prospective observational cross-sectional study in a representative sample of 124 hospitals of the Spanish health services, based on records in the HERMES-AF database (Hospital Emergency Department Management Strategies for AF) for May 23 to June 5, 2011. Patients with symptomatic AF within 48 hours of onset were enrolled when the decision was made to attempt restoration of sinus rhythm. Results: We included 337 patients. Chemical cardioversion was used in 311 (92.3%) and electrical cardioversion in 52 (15%), after drugs had failed in half the cases. Sinus rhythm was restored in 278 patients (82.5%), and symptoms resolved in 94%. Adverse effects were recorded in 0.9% but none were serious. Amiodarone was independently associated with a lower rate of restored sinus rhythm (odds ratio [OR], 0.442; 95% CI, 0.238-0.823; P=.01) than electrical cardioversion (OR, 4.0; 95% CI, 1.2-13.3; P=.024). The use of class Ic antiarrhythmic agents was associated with a higher percentage of discharges in less than 6 hours (OR, 2.6; 95% CI, 1.6-4.3; P<.001), and amiodarone was associated with hospital stays longer than 24 hours (OR, 2.7; 95% CI, 1.5-4.8; P<.003). Conclusions: Emergency department restoration of sinus rhythm in patients with AF is safe, effective, and associated with clinical benefits. Quality of care could be improved by replacing the use of amiodarone with faster and more effective treatments such as electrical cardioversion or the use of class Ic agents


Assuntos
Humanos , Feminino , Pessoa de Meia-Idade , Cardioversão Elétrica/métodos , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/terapia , Serviços Médicos de Emergência , Ritmo Circadiano/efeitos dos fármacos , Sistema de Registros/normas , Cardioversão Elétrica/tendências , Estudos Prospectivos , Estudos Transversais , Espanha , Antiarrítmicos/administração & dosagem , Sistemas de Saúde/organização & administração
2.
Emergencias ; 31(4): 227-233, 2019.
Artigo em Espanhol, Inglês | MEDLINE | ID: mdl-31347801

RESUMO

OBJECTIVES: To analyze heart rate control in hospital emergency departments and outcomes in patients with recent onset atrial fibrillation (AF) so that targets for improvement can be identified. MATERIAL AND METHODS: Multicenter, prospective observational cross-sectional study in a representative sample of 124 hospitals of the Spanish health services, based on records in the HERMES-AF database (Hospital Emergency Department Management Strategies for AF) for May 23 to June 5, 2011. Patients with symptomatic AF within 48 hours of onset were enrolled when the decision was made to attempt restoration of sinus rhythm. RESULTS: We included 337 patients. Chemical cardioversion was used in 311 (92.3%) and electrical cardioversion in 52 (15%), after drugs had failed in half the cases. Sinus rhythm was restored in 278 patients (82.5%), and symptoms resolved in 94%. Adverse effects were recorded in 0.9% but none were serious. Amiodarone was independently associated with a lower rate of restored sinus rhythm (odds ratio [OR], 0.442; 95% CI, 0.238-0.823; P=.01) than electrical cardioversion (OR, 4.0; 95% CI, 1.2-13.3; P=.024). The use of class Ic antiarrhythmic agents was associated with a higher percentage of discharges in less than 6 hours (OR, 2.6; 95% CI, 1.6-4.3; P< .001), and amiodarone was associated with hospital stays longer than 24 hours (OR, 2.7; 95% CI, 1.5-4.8; P< .003). CONCLUSION: Emergency department restoration of sinus rhythm in patients with AF is safe, effective, and associated with clinical benefits. Quality of care could be improved by replacing the use of amiodarone with faster and more effective treatments such as electrical cardioversion or the use of class Ic agents.

3.
Clin Infect Dis ; 69(11): 2015-2018, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-30869755

RESUMO

A patient with a trauma-related left tibial infection associated with extensively drug-resistant Acinetobacter baumannii and multidrug-resistant Klebsiella pneumoniae was treated with bacteriophages and antibiotics. There was rapid tissue healing and positive culture eradication. As a result, the patient's leg did not have to be amputated and he is undergoing rehabilitation.

4.
Acad Emerg Med ; 26(9): 1034-1043, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30703274

RESUMO

BACKGROUND: Although rhythm control has failed to demonstrate long-term benefits over rate control in longstanding episodes of atrial fibrillation (AF), there is little evidence concerning recent-onset ones. We analyzed the benefits of rhythm and rate control in terms of symptoms alleviation and need for hospital admission in patients with recent-onset AF. METHODS: This was a multicenter, observational, cross-sectional study with prospective standardized data collection carried out in 124 emergency departments (EDs). Clinical variables, treatment effectiveness, and outcomes (control of symptoms, final disposition) were analyzed in stable patients with recent-onset AF consulting for AF-related symptoms. RESULTS: Of 421 patients included, rhythm control was chosen in 352 patients (83.6%), a global effectiveness of 84%. Rate control was performed in 69 patients (16.4%) and was achieved in 67 (97%) of them. Control of symptoms was achieved in 396 (94.1%) patients and was associated with a heart rate after treatment ≤ 110 beats/min (odds ratio [OR] = 14.346, 95% confidence interval [CI] = 3.90 to 52.70, p < 0.001) and a rhythm control strategy (OR = 2.78, 95% CI = 1.02 to 7.61, p = 0.046). Sixty patients (14.2%) were admitted: discharge was associated with a rhythm control strategy (OR = 2.22, 95% CI = 1.20-4.60, p = 0.031) and admission was associated with a heart rate > 110 beats/min after treatment (OR = 29.71, 95% CI = 7.19 to 123.07, p < 0.001) and acute heart failure (OR = 9.45, 95% CI = 2.91 to 30.65, p < 0.001). CONCLUSION: In our study, recent-onset AF patients in whom rhythm control was attempted in the ED had a high rate of symptoms' alleviation and a reduced rate of hospital admissions.

5.
Stroke ; 48(5): 1344-1352, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28389612

RESUMO

BACKGROUND AND PURPOSE: Long-term benefits of initiating stroke prophylaxis in the emergency department (ED) are unknown. We analyzed the long-term safety and benefits of ED prescription of anticoagulation in atrial fibrillation patients. METHODS: Prospective, multicenter, observational cohort of consecutive atrial fibrillation patients was performed in 62 Spanish EDs. Clinical variables and thromboprophylaxis prescribed at discharge were collected at inclusion. Follow-up at 1 year post-discharge included data about thromboprophylaxis and its complications, major bleeding, and death; risk was assessed with univariate and bivariate logistic regression models. RESULTS: We enrolled 1162 patients, 1024 (88.1%) at high risk according to CHA2DS2-VASc score. At ED discharge, 935 patients (80.5%) were receiving anticoagulant therapy, de novo in 237 patients (55.2% of 429 not previously treated). At 1 year, 48 (4.1%) patients presented major bleeding events, and 151 (12.9%) had died. Anticoagulation first prescribed in the ED was not related to major bleeding (hazard ratio, 0.976; 95% confidence interval, 0.294-3.236) and was associated with a decrease in mortality (hazard ratio, 0.398; 95% confidence interval, 0.231-0.686). Adjusting by the main clinical and sociodemographic characteristics, concomitant antiplatelet treatment, or destination (discharge or admission) did not affect the results. CONCLUSIONS: Prescription of anticoagulation in the ED does not increase bleeding risk in atrial fibrillation patients at high risk of stroke and contributes to decreased mortality.


Assuntos
Anticoagulantes/farmacologia , Fibrilação Atrial/terapia , Serviço Hospitalar de Emergência/estatística & dados numéricos , Acidente Vascular Cerebral/prevenção & controle , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes/efeitos adversos , Fibrilação Atrial/mortalidade , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Espanha/epidemiologia , Acidente Vascular Cerebral/mortalidade
6.
mBio ; 8(1)2017 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-28096488

RESUMO

Bacteriophages infect an estimated 1023 to 1025 bacterial cells each second, many of which carry physiologically relevant plasmids (e.g., those encoding antibiotic resistance). However, even though phage-plasmid interactions occur on a massive scale and have potentially significant evolutionary, ecological, and biomedical implications, plasmid fate upon phage infection and lysis has not been investigated to date. Here we show that a subset of the natural lytic phage population, which we dub "superspreaders," releases substantial amounts of intact, transformable plasmid DNA upon lysis, thereby promoting horizontal gene transfer by transformation. Two novel Escherichia coli phage superspreaders, SUSP1 and SUSP2, liberated four evolutionarily distinct plasmids with equal efficiency, including two close relatives of prominent antibiotic resistance vectors in natural environments. SUSP2 also mediated the extensive lateral transfer of antibiotic resistance in unbiased communities of soil bacteria from Maryland and Wyoming. Furthermore, the addition of SUSP2 to cocultures of kanamycin-resistant E. coli and kanamycin-sensitive Bacillus sp. bacteria resulted in roughly 1,000-fold more kanamycin-resistant Bacillus sp. bacteria than arose in phage-free controls. Unlike many other lytic phages, neither SUSP1 nor SUSP2 encodes homologs to known hydrolytic endonucleases, suggesting a simple potential mechanism underlying the superspreading phenotype. Consistent with this model, the deletion of endonuclease IV and the nucleoid-disrupting protein ndd from coliphage T4, a phage known to extensively degrade chromosomal DNA, significantly increased its ability to promote plasmid transformation. Taken together, our results suggest that phage superspreaders may play key roles in microbial evolution and ecology but should be avoided in phage therapy and other medical applications. IMPORTANCE: Bacteriophages (phages), viruses that infect bacteria, are the planet's most numerous biological entities and kill vast numbers of bacteria in natural environments. Many of these bacteria carry plasmids, extrachromosomal DNA elements that frequently encode antibiotic resistance. However, it is largely unknown whether plasmids are destroyed during phage infection or released intact upon phage lysis, whereupon their encoded resistance could be acquired and manifested by other bacteria (transformation). Because phages are being developed to combat antibiotic-resistant bacteria and because transformation is a principal form of horizontal gene transfer, this question has important implications for biomedicine and microbial evolution alike. Here we report the isolation and characterization of two novel Escherichia coli phages, dubbed "superspreaders," that promote extensive plasmid transformation and efficiently disperse antibiotic resistance genes. Our work suggests that phage superspreaders are not suitable for use in medicine but may help drive bacterial evolution in natural environments.


Assuntos
Bacteriólise , Colífagos/crescimento & desenvolvimento , DNA Bacteriano/genética , Escherichia coli/virologia , Transferência Genética Horizontal , Transformação Bacteriana , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Maryland , Plasmídeos , Wyoming
7.
Ann Emerg Med ; 65(1): 1-12, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25182543

RESUMO

STUDY OBJECTIVE: We determine the prevalence of stroke prophylaxis prescription in emergency department (ED) patients with atrial fibrillation and the factors associated with a lack of prescription of anticoagulation in high-risk patients without contraindications. METHODS: This was a multicenter, observational, cross-sectional study with prospective standardized data collection carried out in 124 Spanish EDs. Clinical variables, risk factors for stroke, type of prophylaxis prescribed, and reasons for not prescribing anticoagulation in high-risk patients (congestive heart failure/left ventricular dysfunction, hypertension, age >75 years, diabetes and previous stroke/transient ischemic attack/systemic embolism [CHADS2] score ≥2 and the congestive heart failure/left ventricular dysfunction, hypertension, age >75 years, diabetes, previous stroke/transient ischemic attack/systemic embolism, vascular disease age 65 to 74 years and sex category [CHA2DS2-VASc] score ≥2) without contraindications were collected. RESULTS: Of 3,276 patients enrolled, 71.5% were at high risk according to CHADS2; 89.7% according to CHA2DS2-VASc. At discharge from the ED, 2,255 patients (68.8%) were receiving anticoagulants, 1,691 of whom (75%) were high-risk patients. Of the 1,931 patients discharged home, anticoagulation was prescribed for 384 patients (19.9%) de novo and for 932 patients (48.3%) previously receiving anticoagulation. The main reasons for not prescribing anticoagulation to eligible patients were considering antiplatelet therapy as adequate prophylaxis (33.1%), advanced age (15%), and considering stroke risk as low (8.3%). Advanced age (odds ratio 0.46; 95% confidence interval 0.30 to 0.69) and female sex (odds ratio 0.50; 95% confidence interval 0.36 to 0.71) were significantly associated with the lack of prescription of anticoagulation to eligible patients. CONCLUSION: In Spain, most patients with atrial fibrillation treated in EDs who do not receive anticoagulation are at high risk of stroke, with relevant differences with regard to the risk stratification scheme used. Anticoagulation is underused, mainly because the risk of stroke is underestimated by the treating physicians and the benefits of antiplatelets are overrated, principally in female patients and the elderly. Efforts to increase the prescription of anticoagulation in these patients appear warranted.


Assuntos
Fibrilação Atrial/complicações , Serviço Hospitalar de Emergência , Acidente Vascular Cerebral/prevenção & controle , Fatores Etários , Idoso , Anticoagulantes/uso terapêutico , Estudos Transversais , Serviço Hospitalar de Emergência/estatística & dados numéricos , Feminino , Humanos , Masculino , Padrões de Prática Médica/estatística & dados numéricos , Medição de Risco , Fatores de Risco , Fatores Sexuais , Espanha/epidemiologia
8.
RNA ; 20(4): 551-8, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24501251

RESUMO

In S. cerevisiae, the 5'-3' exonuclease Rat1p partakes in transcription termination. Although Rat1p-mediated RNA degradation has been suggested to play a role for this activity, the exact mechanisms by which Rat1p helps release RNA polymerase II (RNAPII) from the DNA template are poorly understood. Here we describe a function of Rat1p in regulating phosphorylation levels of the C-terminal domain (CTD) of the largest RNAPII subunit, Rpb1p, during transcription elongation. The rat1-1 mutant exhibits highly elevated levels of CTD phosphorylation as well as RNAPII distribution and transcription termination defects. These phenotypes are all rescued by overexpression of the CTD phosphatase Fcp1p, suggesting a functional relationship between the absence of Rat1p activity, elevated CTD phosphorylation, and transcription defects. We also demonstrate that rat1-1 cells display increased RNAPII transcription kinetics, a feature that may contribute to the cellular phenotypes of the mutant. Consistently, the rat1-1 allele is synthetic lethal with the rpb1-E1103G mutation, causing increased RNAPII speed, and is suppressed by the rpb2-10 mutation, causing slowed transcription. Thus, Rat1p plays more complex roles in controlling transcription than previously thought.


Assuntos
Exorribonucleases/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Proteínas Quinases/metabolismo , RNA Polimerase II/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Western Blotting , Cromatina/genética , Imunoprecipitação da Cromatina , Exorribonucleases/genética , Fenótipo , Fosfoproteínas Fosfatases/genética , Fosforilação , Proteínas Quinases/genética , Estrutura Terciária de Proteína , RNA Polimerase II/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Serina/genética , Serina/metabolismo , Transcrição Genética
9.
RNA ; 19(10): 1363-71, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23962665

RESUMO

Sub2p/UAP56 is a highly conserved DEAD-box RNA helicase involved in the packaging and nuclear export of mRNA/protein particles (mRNPs). In Saccharomyces cerevisiae, Sub2p is recruited to active chromatin by the pentameric THO complex and incorporated into the larger transcription-export (TREX) complex. Sub2p also plays a role in the maintenance of genome integrity as its inactivation causes severe transcription-dependent recombination of DNA. Despite the central role of Sub2p in early mRNP biology, little is known about its function. Here, we report the presence of an N-terminal motif (NTM) conserved specifically in the Sub2p branch of RNA helicases. Mutation of the NTM causes nuclear accumulation of poly(A)(+) RNA and impaired growth without affecting core helicase functions. Thus, the NTM functions as an autonomous unit. Moreover, two sub2 mutants, that are deficient in ATP binding, act in a trans-dominant negative fashion for growth and induce high recombination rates in vivo. Although wild-type Sub2p is prevented access to transcribed loci in such a background, this does not mechanistically explain the phenotype.


Assuntos
Adenosina Trifosfatases/genética , Instabilidade Genômica , Mutação/genética , Transporte de RNA/genética , RNA Fúngico/genética , RNA Mensageiro/genética , Saccharomyces cerevisiae/genética , Adenosina Trifosfatases/química , Adenosina Trifosfatases/metabolismo , Western Blotting , Núcleo Celular/genética , Cromatina/genética , Imunoprecipitação da Cromatina , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Transcrição Genética
10.
RNA ; 19(9): 1200-7, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23893733

RESUMO

It has recently been demonstrated that ribosomes are preferentially localized outside the nucleoid in Escherichia coli, but little is known about the spatial regulation of pre-rRNA processing. In this work, I investigate the cellular distribution of leader pre-rRNAs using RNA-FISH. In contrast to mature rRNA, the 5' proximal leader region associates with the nucleoid, and this association occurs in an RNase III-dependent manner. Moreover, RNase III plays a role in the rapid induction of ribosomal operons during outgrowth and is essential in the absence of the transcriptional regulator Fis, suggesting a linkage of transcription and RNA processing for ribosomal operons in E. coli.


Assuntos
Proteínas de Escherichia coli/genética , Escherichia coli/metabolismo , Precursores de RNA/metabolismo , RNA Bacteriano/metabolismo , Ribonuclease III/genética , Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Modelos Moleculares , Conformação de Ácido Nucleico , Precursores de RNA/genética , RNA Bacteriano/genética , RNA Ribossômico/metabolismo , Ribonuclease III/metabolismo , Subunidades Ribossômicas Menores/metabolismo , Transcrição Genética
11.
J Biol Chem ; 288(4): 2689-99, 2013 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-23223234

RESUMO

The fidelity of RNA synthesis depends on both accurate template-mediated nucleotide selection and proper maintenance of register between template and RNA. Loss of register, or transcriptional slippage, is particularly likely on homopolymeric runs in the template. Transcriptional slippage can alter the coding capacity of mRNAs and is used as a regulatory mechanism. Here we describe mutations in the largest subunit of Saccharomyces cerevisiae RNA polymerase II that substantially increase the level of transcriptional slippage. Alleles of RPB1 (RPO21) with elevated slippage rates were identified among 6-azauracil-sensitive mutants and were also isolated using a slippage-dependent reporter gene. Biochemical characterization of polymerase II isolated from these mutants confirms elevated levels of transcriptional slippage.


Assuntos
Regulação Fúngica da Expressão Gênica , Mutação , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Alelos , Sequência de Aminoácidos , Sequência de Bases , Domínio Catalítico , Cromossomos/ultraestrutura , Modelos Moleculares , Conformação Molecular , Dados de Sequência Molecular , Oligonucleotídeos/genética , Ligação Proteica , RNA/metabolismo , Transcrição Genética , beta-Galactosidase/metabolismo
12.
RNA Biol ; 8(2): 184-9, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21358276

RESUMO

T-bodies are localized S. cerevisiae RNPs containing Ty1 retroviral components and speculated to play a role in the assembly of virus-like particles (VLPs). Mapping requirements for T-body formation, we demonstrate that ectopic expression of immature TyA1/Gag (Gag-p49), a structural component of the Ty1 capsid, is sufficient for T-body formation both under normal conditions as well as in a strain background devoid of endogenous Gag. Moreover, T-bodies are readily formed when Ty1 transposition is blocked. Thus, T-bodies represent an early stage in the Ty1 life cycle, preceding VLP maturation.


Assuntos
Produtos do Gene gag/genética , Retroelementos/genética , Ribonucleoproteínas/biossíntese , Saccharomyces cerevisiae/genética , Regulação Fúngica da Expressão Gênica , Produtos do Gene gag/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/metabolismo
13.
Mol Cell ; 37(4): 580-7, 2010 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-20188675

RESUMO

Termination of RNA polymerase II (RNAPII) transcription of protein-coding genes occurs downstream of cleavage/polyadenylation sites. According to the "torpedo" model, the 5'-3' exonuclease Rat1p/Xrn2p attacks the newly formed 5' end of the cleaved pre-mRNA, causing the still transcribing RNAPII to terminate. Here we demonstrate a similar role of S. cerevisiae Rat1p within the gene body. We find that the transcription processivity defect imposed on RNAPII by the rpb1-N488D mutation is corrected upon Rat1p inactivation. Importantly, Rat1p-dependent transcription termination occurs upstream the polyadenylation site. Genetic and biochemical evidence demonstrate that mRNA capping is defective in rpb1-N488D cells, which leads to increased levels of Rat1p all along the gene locus. Consistently, Rat1p-dependent RNAPII termination is also observed in the capping-deficient ceg1-63 strain. Our data suggest that Rat1p serves to terminate RNAPII molecules engaged in the production of uncapped RNA, regardless of their position on the gene locus.


Assuntos
Exorribonucleases/metabolismo , Capuzes de RNA/biossíntese , RNA Polimerase II/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Transcrição Genética , Exorribonucleases/genética , Regulação Fúngica da Expressão Gênica , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Capuzes de RNA/genética , RNA Polimerase II/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
14.
J Biol Chem ; 284(29): 19601-12, 2009 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-19439405

RESUMO

Rpb9 is a small non-essential subunit of yeast RNA polymerase II located on the surface on the enzyme. Deletion of the RPB9 gene shows synthetic lethality with the low fidelity rpb1-E1103G mutation localized in the trigger loop, a mobile element of the catalytic Rpb1 subunit, which has been shown to control transcription fidelity. Similar to the rpb1-E1103G mutation, the RPB9 deletion substantially enhances NTP misincorporation and increases the rate of mismatch extension with the next cognate NTP in vitro. Using pre-steady state kinetic analysis, we show that RPB9 deletion promotes sequestration of NTPs in the polymerase active center just prior to the phosphodiester bond formation. We propose a model in which the Rpb9 subunit controls transcription fidelity by delaying the closure of the trigger loop on the incoming NTP via interaction between the C-terminal domain of Rpb9 and the trigger loop. Our findings reveal a mechanism for regulation of transcription fidelity by protein factors located at a large distance from the active center of RNA polymerase II.


Assuntos
Proteínas Fúngicas/metabolismo , Nucleotídeos/metabolismo , RNA Polimerase II/metabolismo , Transcrição Genética , Trifosfato de Adenosina/metabolismo , Sequência de Bases , Citidina Trifosfato/metabolismo , Proteínas Fúngicas/genética , Cinética , Modelos Moleculares , Mutação , Conformação Proteica , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , RNA Polimerase II/química , RNA Polimerase II/genética , Fatores de Tempo , Uridina Trifosfato/metabolismo
15.
Mol Cell Biol ; 28(19): 6022-32, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18678648

RESUMO

A large share of mRNA processing and packaging events occurs cotranscriptionally. To explore the hypothesis that transcription defects may affect mRNA fate, we analyzed poly(A)(+) RNA distribution in Saccharomyces cerevisiae strains harboring mutations in Rpb1p, the largest subunit of RNA polymerase II. In certain rpb1 mutants, a poly(A)(+) RNA granule, distinct from any known structure, strongly accumulated in a confined space of the cytoplasm. RNA and protein expressed from Ty1 retrovirus-like elements colocalized with this new granule, which we have consequently named the T body. A visual screen revealed that the deletion of most genes with proposed functions in Ty1 biology unexpectedly does not alter T-body levels. In contrast, the deletion of genes encoding the Mediator transcription initiation factor subunits Srb2p and Srb5p as well as the Ty1 transcriptional regulator Spt21p greatly enhances T-body formation. Our data disclose a new cellular body putatively involved in the assembly of Ty1 particles and suggest that the cytoplasmic fate of mRNA can be affected by transcription initiation events.


Assuntos
Grânulos Citoplasmáticos/química , RNA Fúngico/genética , Retroelementos , Saccharomyces cerevisiae/genética , Grânulos Citoplasmáticos/genética , Grânulos Citoplasmáticos/metabolismo , Proteínas Fúngicas/análise , RNA Fúngico/análise , RNA Fúngico/metabolismo , RNA Mensageiro/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Fatores de Transcrição/genética
16.
Mol Cell ; 30(5): 557-66, 2008 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-18538654

RESUMO

To study fidelity of RNA polymerase II (Pol II), we analyzed properties of the 6-azauracil-sensitive and TFIIS-dependent E1103G mutant of rbp1 (rpo21), the gene encoding the catalytic subunit of Pol II in Saccharomyces cerevisiae. Using an in vivo retrotransposition-based transcription fidelity assay, we observed that rpb1-E1103G causes a 3-fold increase in transcription errors. This mutant showed a 10-fold decrease in fidelity of transcription elongation in vitro. The mutation does not appear to significantly affect translocation state equilibrium of Pol II in a stalled elongation complex. Primarily, it promotes NTP sequestration in the polymerase active center. Furthermore, pre-steady-state analyses revealed that the E1103G mutation shifted the equilibrium between the closed and the open active center conformations toward the closed form. Thus, open conformation of the active center emerges as an intermediate essential for preincorporation fidelity control. Similar mechanisms may control fidelity of DNA-dependent DNA polymerases and RNA-dependent RNA polymerases.


Assuntos
Regulação Fúngica da Expressão Gênica , Mutação/genética , RNA Polimerase II/química , RNA Polimerase II/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Transcrição Genética , Sequência de Aminoácidos , Substituição de Aminoácidos , Sítios de Ligação , Domínio Catalítico , Isomerismo , Dados de Sequência Molecular , Nucleotídeos/metabolismo , RNA Polimerase II/genética , Retroelementos/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Alinhamento de Sequência , Especificidade por Substrato
17.
Genetics ; 172(4): 2201-9, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16510790

RESUMO

RNA polymerase II (RNAPII) in eukaryotic cells drives transcription of most messenger RNAs. RNAPII core enzyme is composed of 12 polypeptides where Rpb1 is the largest subunit. To further understand the mechanisms of RNAPII transcription, we isolated and characterized novel point mutants of RPB1 that are sensitive to the nucleotide-depleting drug 6-azauracil (6AU). In this work we reisolated the rpo21-24/rpb1-E1230K allele, which reduces the interaction of RNAPII-TFIIS, and identified five new point mutations in RPB1 that cause hypersensitivity to 6AU. The novel mutants affect highly conserved residues of Rpb1 and have differential genetic and biochemical effects. Three of the mutations affect the "lid" and "rudder," two small loops suggested by structural studies to play a central role in the separation of the RNA-DNA hybrids. Most interestingly, two mutations affecting the catalytic center (rpb1-N488D) and the homology box G (rpb1-E1103G) have strong opposite effects on the intrinsic in vitro polymerization rate of RNAPII. Moreover, the synthetic interactions of these mutants with soh1, spt4, and dst1 suggest differential in vivo effects.


Assuntos
Mutação , RNA Polimerase II/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Uracila/análogos & derivados , Sequência de Aminoácidos , Antimetabólitos/farmacologia , Domínio Catalítico , DNA/química , Dados de Sequência Molecular , Peptídeos/química , Mutação Puntual , RNA/química , RNA Polimerase II/química , RNA Polimerase II/metabolismo , RNA Mensageiro/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Homologia de Sequência de Aminoácidos , Uracila/farmacologia
18.
Cir Esp ; 79(1): 64-6, 2006 Jan.
Artigo em Espanhol | MEDLINE | ID: mdl-16426536

RESUMO

Endometriosis consists of the presence of extrauterine endometrial tissue. It is usually localized in the pelvis, although it can also be found in other sites. Cutaneous localization is unusual and the most frequent form appears on scars from obstetric or gynecological interventions. It can, however, develop spontaneously, especially in umbilical or inguinal areas and can be confused with irreducible hernias or granulomas. We present the cases of three patients with spontaneous endometriotic nodules of the abdominal wall. The lesions were located in the umbilical region in two patients and in the suprapubic area in one. In two patients clinical suspicion led to preoperative diagnosis, although diagnosis is usually established after histopathological analysis of the surgical specimen.


Assuntos
Parede Abdominal , Endometriose/diagnóstico , Neoplasias Musculares/diagnóstico , Doenças Musculares/diagnóstico , Adulto , Diagnóstico Diferencial , Feminino , Humanos
19.
Cir. Esp. (Ed. impr.) ; 79(1): 64-66, ene. 2006. ilus
Artigo em Espanhol | IBECS | ID: ibc-042430

RESUMO

Se denomina endometriosis a la presencia de tejido endometrial extrauterino. Su localización habitual es intrapélvica, aunque puede localizarse en otros lugares. La localización cutánea es rara y la forma más frecuente aparece sobre cicatrices de intervenciones ginecológicas u obstétricas, aunque puede aparecer de forma espontánea, sobre todo en la zona umbilical o inguinal, y puede confundirse con hernias no reductibles o granulomas. Presentamos los casos de 3 pacientes con nódulos endometriósicos espontáneos en las pared abdominal, dos en localización umbilical y otro suprapúbico, en dos de los cuales se pudo establecer el diagnóstico preoperatoriamente ante la sospecha clínica, aunque lo habitual es que el diagnóstico se establezca tras el estudio anatomopatológico de la pieza de resección (AU)


Endometriosis consists of the presence of extrauterine endometrial tissue. It is usually localized in the pelvis, although it can also be found in other sites. Cutaneous localization is unusual and the most frequent form appears on scars from obstetric or gynecological interventions. It can, however, develop spontaneously, especially in umbilical or inguinal areas and can be confused with irreducible hernias or granulomas. We present the cases of three patients with spontaneous endometriotic nodules of the abdominal wall. The lesions were located in the umbilical region in two patients and in the suprapubic area in one. In two patients clinical suspicion led to preoperative diagnosis, although diagnosis is usually established after histopathological analysis of the surgical specimen (AU)


Assuntos
Feminino , Adulto , Humanos , Endometriose/diagnóstico , Neoplasias Abdominais/diagnóstico , Diagnóstico Diferencial , Endometriose/fisiopatologia
20.
Genetics ; 168(1): 553-7, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15454565

RESUMO

We isolated a novel rad52 mutation, rad52-L89F, which specifically impairs recombination in rad51Delta cells. rad52-L89F displays phenotypes similar to rad59Delta and encodes a mutant protein impaired in its ability to interact with Rad59. These results support the idea that Rad59 acts in homologous recombination via physical interaction with Rad52.


Assuntos
Proteínas de Ligação a DNA/genética , Mutação/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Sequência de Aminoácidos , Proteínas de Ligação a DNA/metabolismo , Eletroforese em Gel de Poliacrilamida , Metanossulfonato de Metila , Dados de Sequência Molecular , Rad51 Recombinase , Proteína Rad52 de Recombinação e Reparo de DNA , Recombinação Genética/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Alinhamento de Sequência
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