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1.
Pain Ther ; 6(1): 73-84, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28451867

RESUMEN

INTRODUCTION: The prevalence of prescription opioid use disorders in the US has increased markedly in parallel with increases in opioid prescribing. Whilst an increase in opioid prescribing has also occurred in the UK, it remains unknown if there have been concurrent increases in opioid use disorders. The aim of this study was to examine national trends in the prevalence and incidence of physician-diagnosed opioid use disorders in the UK. METHODS: In a retrospective electronic health care database analysis using data from the UK Clinical Practice Research Datalink (CPRD), we identified persons receiving a first opioid prescription between January 1, 2008 and December 31, 2012. Persons with an opioid use disorder were identified by Read codes assigned by patients' physicians within 6 months following an opioid prescription. We calculated prevalence and incidence rates by dividing the analysis population by the total number of patients exposed (prevalence) or the total patient-years of exposure (incidence) using the 'exact' Clopper-Pearson Binomial method. RESULTS: Our analysis included 714,699 person-years of prescription opioid exposure. The 5-year period prevalence of opioid use disorders was 4.61 (95% CI 4.28-4.96) per 10,000 individuals, or 0.05%. The incidence rate of opioid use disorders was of 6.51 (95% CI 5.93-7.13) patients per 10,000 patient-years exposed. When examined by study year, there was no clear suggestion of a changing trend over time. When stratified by opioid drug, trends in the incidence rate during the study were either stable (i.e., codeine and tramadol), increasing (i.e., morphine) or decreasing (i.e., dihydrocodeine). CONCLUSIONS: Our study demonstrates that despite the marked increase in overall opioid prescribing in the UK in the past decade, there has not been an increase in the incidence of physician-diagnosed opioid use disorders.

2.
J Invest Dermatol ; 134(11): 2823-2832, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24999593

RESUMEN

As the outermost barrier of the body, the skin is exposed to multiple environmental factors, including temperature, humidity, mechanical stress, and chemical stimuli such as odorants that are often used in cosmetic articles. Keratinocytes, the major cell type of the epidermal layer, express a variety of different sensory receptors that enable them to react to various environmental stimuli and process information in the skin. Here we report the identification of a novel type of chemoreceptors in human keratinocytes, the olfactory receptors (ORs). We cloned and functionally expressed the cutaneous OR, OR2AT4, and identified Sandalore, a synthetic sandalwood odorant, as an agonist of this receptor. Sandalore induces strong Ca(2+) signals in cultured human keratinocytes, which are mediated by OR2AT4, as demonstrated by receptor knockdown experiments using RNA interference. The activation of OR2AT4 induces a cAMP-dependent pathway and phosphorylation of extracellular signal-regulated kinases (Erk1/2) and p38 mitogen-activated protein kinases (p38 MAPK). Moreover, the long-term stimulation of keratinocytes with Sandalore positively affected cell proliferation and migration, and regeneration of keratinocyte monolayers in an in vitro wound scratch assay. These findings combined with our studies on human skin organ cultures strongly indicate that the OR 2AT4 is involved in human keratinocyte re-epithelialization during wound-healing processes.


Asunto(s)
Regulación de la Expresión Génica , Queratinocitos/citología , Queratinocitos/metabolismo , Receptores Odorantes/metabolismo , Santalum/química , Cicatrización de Heridas , Calcio/química , Movimiento Celular , Proliferación Celular , Clonación Molecular , Células HEK293 , Humanos , Sistema de Señalización de MAP Quinasas , Odorantes , Neuronas Receptoras Olfatorias/metabolismo , Interferencia de ARN , Transducción de Señal , Piel/metabolismo
3.
Front Neurol ; 4: 136, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24106487

RESUMEN

OBJECTIVE: Despite the high prevalence of vertigo globally and an acknowledged, but under-reported, effect on an individual's wellbeing, few studies have evaluated the burden on healthcare systems and society. This study was aimed to quantitatively determine the impact of vertigo on healthcare resource use and work productivity. METHODS: The economic burden of vertigo was assessed through a multi-country, non-interventional, observational registry of vertigo patients: the Registry to Evaluate the Burden of Disease in Vertigo. Patients included were those with a new diagnosis of Meniere's disease, benign paroxysmal positional vertigo, other vertigo of peripheral vestibular origin, or peripheral vestibular vertigo of unknown origin. RESULTS: A total of 4,294 patients at 618 centers in 13 countries were included during the registry. Of the 4,105 patients analyzed, only half were in employment. Among this working patient population, 69.8% had reduced their workload, 63.3% had lost working days, and 4.6% had changed and 5.7% had quit their jobs, due to vertigo symptoms. Use of healthcare services among patients was high. In the 3 months preceding Visit 1, patients used emergency services 0.4 ± 0.9 times, primary care consultations 1.6 ± 1.8 times, and specialist consultations 1.4 ± 2.0 times (all mean ± SD). A mean of 2.0 ± 5.4 days/patient was also spent in hospital due to vertigo. CONCLUSION: In addition to the negative impact on the patient from a humanistic perspective, vertigo has considerable impact on work productivity and healthcare resource use.

4.
Expert Opin Investig Drugs ; 22(9): 1167-79, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23815605

RESUMEN

INTRODUCTION: Chronic pruritus (CP), defined as itch lasting for > 6 weeks, is a burdensome symptom of several different diseases, dermatological and systemic, with a high negative impact on the quality of life of patients. Given the manifold aetiologies of CP, therapy is often difficult. In recent years, however, novel substances have been developed for treatment of certain CP entities and identified targets. AREAS COVERED: In this review, the authors present a survey of targets currently believed to be promising (H4R, IL-31, MOR, KOR, GRPR, NGF, NK-1R, TRP channels) and related investigational drugs that are in the preclinical or clinical stage of development. Some substances have already undergone clinical testing, but only one of them (nalfurafine) has been licensed so far. Many of them are most likely to exert their effects on the skin and interfere there with the cutaneous neurobiology of CP. EXPERT OPINION: Currently, the most promising candidates for new therapeutic agents in CP are neurokinin-1 receptor antagonists and substances targeting the kappa- or mu-opioid receptor, or both. They have the potential to target the neuronal pathway of CP and are thus of interest for several CP entities. The goal for the coming years is to validate these concepts and move forward in developing new drugs for the therapy of CP.


Asunto(s)
Drogas en Investigación/uso terapéutico , Terapia Molecular Dirigida , Prurito/tratamiento farmacológico , Animales , Enfermedad Crónica , Diseño de Fármacos , Drogas en Investigación/farmacología , Humanos , Calidad de Vida , Piel/efectos de los fármacos , Piel/metabolismo
5.
Front Neurol ; 4: 48, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23675366

RESUMEN

INTRODUCTION: Despite being a common disease, data on vertigo management in a real-world setting are scarce. AIMS: To provide information on the vertigo and its management in a real-world setting. METHODS: Data were collected from 4,294 patients with vertigo in 13 countries over 28 months via a multi-national, non-interventional observational study (the so-called REVERT registry). Data included medical history and details of anti-vertigo therapy. "Clinical global impression" (CGI) of severity (CGI-S) was assessed at baseline (V1) and then at 6 months follow-up (V2) along with CGI change (CGI-C). All variables were analyzed descriptively. RESULTS: The majority of patients were female, >40 years of age, and almost half had co-morbid cardio-vascular disease. Diagnoses were split into four categories: 37.2% "other vertigo of peripheral vestibular origin," 26.9% benign paroxysmal positional vertigo (BPPV), 20.5% "peripheral vestibular vertigo of unknown origin," and 15.4% Ménière's disease (MD). Betahistine was the most commonly prescribed therapy prior to and after enrollment, and was followed by piracetam, ginkgo biloba, and diuretics. MD had the highest proportion of betahistine treated patients. Almost half of patients were "moderately ill" at V1 based on CGI-S. At V2, patient distribution moved toward "less severe illness" (91.0% improved). The greatest improvements were in the more severely ill, and those with BPPV or "other vertigo of peripheral origin." CONCLUSION: There was a reduction in illness severity over the course of the study, some of which is likely to be due to pharmacological intervention. Further studies are needed to confirm these results.

6.
Int Tinnitus J ; 16(1): 14-24, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-21609908

RESUMEN

This was a 3-month multicentre, open-label post-marketing surveillance study of betahistine (24 mg b.i.d. or 16 mg t.i.d.) in patients with vertigo of peripheral vestibular origin. Study endpoints comprised on-treatment changes in the Dizziness Handicap Index (DHI), Hospital Anxiety and Depression Score (HADS) and the Short-Form (SF)-36v2. Total DHI score improved 37.2 points (of a 100-point scale) following betahistine treatment. Corresponding improvements occurred in all three DHI scale domains (all p < 0.001 vs baseline). Betahistine therapy was also accompanied by progressive, significant improvements in both HADS-A and HADS-D scores (p < 0.001), and improvements in the distribution profiles of anxiety and depression scores. Significant improvements in the Physical Component Summary and Mental Component Summary scores of the SF-36v2 were recorded during betahistine treatment. Betahistine was generally well tolerated. A total of 76 adverse drug reactions (ADRs) were recorded in 49 patients (2.4%), of which 75 were classified as mild or moderate and 54 were possibly related to betahistine. ADRs led to study drug discontinuation in 17 patients. These data illustrate that treatment with betahistine 48 mg/day in patients with recurrent peripheral vestibular vertigo is associated with improvements in objective measures of health-related quality of life and satisfactory tolerability.


Asunto(s)
Betahistina/administración & dosificación , Betahistina/efectos adversos , Vasodilatadores/administración & dosificación , Vasodilatadores/efectos adversos , Vértigo/tratamiento farmacológico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Ansiedad/psicología , Peso Corporal/efectos de los fármacos , Depresión/psicología , Estado de Salud , Humanos , Persona de Mediana Edad , Satisfacción del Paciente , Calidad de Vida , Vértigo/psicología , Vestíbulo del Laberinto/efectos de los fármacos
7.
Histol Histopathol ; 25(2): 177-87, 2010 02.
Artículo en Inglés | MEDLINE | ID: mdl-20017104

RESUMEN

The olfactory epithelium (OE) is unique in regenerating throughout life and thus is an attractive target for examining neurogenesis. The nestin protein was shown to be expressed in the OE of rodents and is suggested to be essentially involved in the process of regeneration. Here we report the expression and distribution of nestin in the human OE at RNA and protein level. Moreover, we analysed the expression profiles in dependence on age and olfactory capacity. After sinus surgery, biopsies were taken from the olfactory epithelium of 16 patients aged 20-80 years with documented differences in their olfactory function. Our studies revealed that nestin is constantly detectable in the apical protuberances of sustentacular cells within the human OE of healthy adults. Its expression is not dependent on age, but rather appears to be related to the olfactory function, as a comparison with specimens obtained from patients suffering either from persistent anosmia or hyposmia suggests. Particularly, in the course of dystrophy, often accompanied with impaired olfaction, nestin expression was occasionally decreased. Contrarily, the expression of the p75-NGFR protein, a marker for human OE basal cells, was not altered, indicating that at least in the tested samples olfactory impairment is not connected with abnormalities at the basal cell level. These observations emphasize an essential role of nestin for the process of regeneration, and also highlight this factor as a candidate marker for sustentacular cells in the human olfactory epithelium.


Asunto(s)
Proteínas de Filamentos Intermediarios/análisis , Proteínas del Tejido Nervioso/análisis , Trastornos del Olfato/metabolismo , Mucosa Olfatoria/química , Células Madre/química , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores/análisis , Biopsia , Femenino , Humanos , Inmunohistoquímica , Proteínas de Filamentos Intermediarios/genética , Masculino , Persona de Mediana Edad , Proteínas del Tejido Nervioso/genética , Nestina , Trastornos del Olfato/patología , Trastornos del Olfato/fisiopatología , Proteína Marcadora Olfativa/análisis , Mucosa Olfatoria/patología , Mucosa Olfatoria/fisiopatología , ARN Mensajero/análisis , Receptores de Factor de Crecimiento Nervioso/análisis , Regeneración , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Olfato , Células Madre/patología , Tubulina (Proteína)/análisis , Adulto Joven
8.
J Pharm Pharm Sci ; 12(1): 116-28, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19470296

RESUMEN

PURPOSE: Transient receptor potential vanilloid-3 (TRPV3) is a thermo-sensitive ion channel expressed in skin keratinocytes and in a variety of neural cells. It is activated by warmth as well as monoterpenoids including camphor, menthol, dihydrocarveol and 1,8-cineol. TRPV3 is described as a putative nociceptor and previous studies revealed sensitization of the channel during repeated short-term stimulation with different agonists. In the present investigation TRPV3 was transiently expressed in either Xenopus oocytes or HEK293 cells. Whole-cell voltage-clamp techniques were used to characterize the behavior of TRPV3 when challenged with different agonists. METHODS: Similarly, a human keratinocyte-derived cell line (HaCaT cells) was used to monitor the behavior of native TRPV3 when challenged with different agonists. RESULTS: We report here that prolonged exposure (5-15 minutes) of monoterpenoids results in agonist-specific desensitization of TRPV3. Long-term exposure to camphor and 1,8-cineol elicits desensitizing currents in TRPV3 expressing oocytes, whereas the non-terpenoid agonist 2-APB induces sustained currents. Agonist-specific desensitization of endogenous TRPV3 was also found in HaCaT cells, which may be taken as a representative for the native system. Terpenoids have a long history of use in therapeutics, pharmaceuticals and cosmetics but knowledge about underpinning molecular mechanisms is incomplete. Our finding on agonist-induced desensitization of TRPV3 by some monoterpenoids displays a novel mechanism through which TRP channels could be functionally modulated. CONCLUSION: Desensitization of TRPV3 channels might be the molecular basis of action for some of the medicinal properties of camphor and 1,8-cineol.


Asunto(s)
Potenciales de la Membrana/efectos de los fármacos , Monoterpenos/farmacología , Canales Catiónicos TRPV/agonistas , Animales , Humanos , Oocitos , Canales Catiónicos TRPV/metabolismo , Xenopus laevis
9.
PLoS One ; 4(5): e5499, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19430528

RESUMEN

The gaseous signalling molecule nitric oxide (NO) is involved in various physiological processes including regulation of blood pressure, immunocytotoxicity and neurotransmission. In the mammalian olfactory bulb (OB), NO plays a role in the formation of olfactory memory evoked by pheromones as well as conventional odorants. While NO generated by the neuronal isoform of NO synthase (nNOS) regulates neurogenesis in the olfactory epithelium, NO has not been implicated in olfactory signal transduction. We now show the expression and function of the endothelial isoform of NO synthase (eNOS) in mature olfactory sensory neurons (OSNs) of adult mice. Using NO-sensitive micro electrodes, we show that stimulation liberates NO from isolated wild-type OSNs, but not from OSNs of eNOS deficient mice. Integrated electrophysiological recordings (electro-olfactograms or EOGs) from the olfactory epithelium of these mice show that NO plays a significant role in modulating adaptation. Evidence for the presence of eNOS in mature mammalian OSNs and its involvement in odorant adaptation implicates NO as an important new element involved in olfactory signal transduction. As a diffusible messenger, NO could also have additional functions related to cross adaptation, regeneration, and maintenance of MOE homeostasis.


Asunto(s)
Óxido Nítrico/biosíntesis , Bulbo Olfatorio/efectos de los fármacos , Células Receptoras Sensoriales/efectos de los fármacos , Terpenos/farmacología , Monoterpenos Acíclicos , Aldehídos/farmacología , Animales , Calcio/metabolismo , Colforsina/farmacología , Electrofisiología , Inhibidores Enzimáticos/farmacología , Epitelio/efectos de los fármacos , Epitelio/metabolismo , Epitelio/fisiología , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Inmunohistoquímica , Hibridación in Situ , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo III/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo III/genética , Óxido Nítrico Sintasa de Tipo III/metabolismo , Bulbo Olfatorio/citología , Bulbo Olfatorio/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células Receptoras Sensoriales/citología , Células Receptoras Sensoriales/metabolismo
10.
RNA ; 15(7): 1305-13, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19447915

RESUMEN

RNA recognition motifs (RRMs) constitute versatile macromolecular interaction platforms. They are found in many components of spliceosomes, in which they mediate RNA and protein interactions by diverse molecular strategies. The human U11/U12-65K protein of the minor spliceosome employs a C-terminal RRM to bind hairpin III of the U12 small nuclear RNA (snRNA). This interaction comprises one side of a molecular bridge between the U11 and U12 small nuclear ribonucleoprotein particles (snRNPs) and is reminiscent of the binding of the N-terminal RRMs in the major spliceosomal U1A and U2B'' proteins to hairpins in their cognate snRNAs. Here we show by mutagenesis and electrophoretic mobility shift assays that the beta-sheet surface and a neighboring loop of 65K C-terminal RRM are involved in RNA binding, as previously seen in canonical RRMs like the N-terminal RRMs of the U1A and U2B'' proteins. However, unlike U1A and U2B'', some 30 residues N-terminal of the 65K C-terminal RRM core are additionally required for stable U12 snRNA binding. The crystal structure of the expanded 65K C-terminal RRM revealed that the N-terminal tail adopts an alpha-helical conformation and wraps around the protein toward the face opposite the RNA-binding platform. Point mutations in this part of the protein had only minor effects on RNA affinity. Removal of the N-terminal extension significantly decreased the thermal stability of the 65K C-terminal RRM. These results demonstrate that the 65K C-terminal RRM is augmented by an N-terminal element that confers stability to the domain, and thereby facilitates stable RNA binding.


Asunto(s)
ARN Nuclear Pequeño/genética , ARN Nuclear Pequeño/metabolismo , Ribonucleoproteína Nuclear Pequeña U1/metabolismo , Ribonucleoproteínas Nucleares Pequeñas/metabolismo , Proteínas Nucleares snRNP/metabolismo , Cristalografía por Rayos X , Ensayo de Cambio de Movilidad Electroforética , Humanos , Modelos Moleculares , Conformación Proteica , Estructura Secundaria de Proteína , Ribonucleoproteína Nuclear Pequeña U1/genética , Ribonucleoproteínas Nucleares Pequeñas/química , Ribonucleoproteínas Nucleares Pequeñas/genética , Empalmosomas , Proteínas Nucleares snRNP/genética
11.
Eur J Cardiovasc Prev Rehabil ; 13(5): 776-83, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17001218

RESUMEN

BACKGROUND: The aim of this study was to determine the achievement of National Cholesterol Education Program Adult Treatment Panel III goals in patients with primary hypercholesterolemia starting statin therapy in clinical practice. METHODS AND RESULTS: Data were collected by 4401 physicians in private practice on 52 848 patients aged 35-65 years (46.3% women, 53.7% men). 56.1% of patients had no manifested atherosclerosis (primary prevention) among whom 34.9% of men and 0.5% of women had a 10-year coronary heart disease risk over 20% (high-risk) as calculated using the Prospective Cardiovascular Münster study (PROCAM) algorithm. After 6 weeks of statins, only 6.9% of these high-risk men and 4.6% of these high-risk women reached their low-density lipoprotein (LDL) cholesterol target of 2.6 mmol/l or below (100 mg/dl). Even after 9 months, only 8.0% of these men and 6.2% of these women achieved their LDL target. No fewer than 57.3% of treated women had a coronary risk below 10%, and 18.8% of women were already at target before statins were prescribed. Of patients 43.9% had manifest atherosclerosis (secondary prevention). After 6 weeks of therapy, only 12.9% of the women and 16.3% of the men in this secondary prevention group reached LDL target levels of 2.6 mmol/l or below. Even after 9 months, only 21.3% of men and 17.3% of women with manifest atherosclerosis reached target LDL. CONCLUSIONS: Most high-risk patients do not achieve LDL targets. Overtreatment of low-risk groups is also very common.


Asunto(s)
Enfermedades Cardiovasculares/prevención & control , Trastornos Cerebrovasculares/prevención & control , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Hipercolesterolemia/tratamiento farmacológico , Guías de Práctica Clínica como Asunto , Pautas de la Práctica en Medicina , Femenino , Humanos , Masculino
12.
Curr Med Res Opin ; 22(4): 631-9, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16684423

RESUMEN

BACKGROUND: While randomized controlled trials (RCTs) generate informative data about clinical outcomes, by their nature they cannot provide information about drug utilization and factors influencing prescribing decisions. In the secondary prevention of patients with cardiac events, lipid lowering therapy with statins and other agents, such as cholesterol absorption inhibitors (CAI, e.g. ezetimibe) plays a pivotal role and is often initiated or modified in rehabilitation centres. The aims of the present study were to analyse factors that influence the prescribing decisions of physicians, and to investigate success rates of lipid lowering therapy with ezetimibe after adjustment for covariates. METHODS: Ninety-three rehabilitation centres throughout Germany documented a total of 17029 patients in cardiac rehabilitation, of which 6976 (41.6%) were prescribed a CAI. A logistic regression model with forward selection based on 31 potential regressors for ezetimibe prescription (demographics, diagnosis, risk factors etc.) was used to construct a propensity score, which reflects the inclination of physicians to prescribe CAI. This score was subsequently used for bias reduction in the comparison of co-medications and success rates. RESULTS: Nineteen variables were associated with ezetimibe prescriptions, the most important ones being total cholesterol, level of education, unstable angina pectoris and arterial hypertension. Ezetimibe was more frequently prescribed together with simvastatin and pravastatin than with other statins, and frequently together with aspirin or beta blockers, respectively. After adjustment for baseline lipid values and covariates, the probability of target level achievement appears to be substantially higher for patients on ezetimibe than for those without ezetimibe. CONCLUSIONS: Other factors than conventional risk factors contribute to the CAI prescription habits of physicians. Additional lipid level reductions due to ezetimibe are seen in routine health care corresponding to findings from randomized studies.


Asunto(s)
Anticolesterolemiantes/uso terapéutico , Azetidinas/uso terapéutico , Revisión de la Utilización de Medicamentos , Hipercolesterolemia/tratamiento farmacológico , Pautas de la Práctica en Medicina , Sistema de Registros , Centros de Rehabilitación , Anciano , Ezetimiba , Femenino , Alemania , Humanos , Masculino , Persona de Mediana Edad , Resultado del Tratamiento
13.
EMBO J ; 24(17): 3057-69, 2005 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-16096647

RESUMEN

U11 and U12 interact cooperatively with the 5' splice site and branch site of pre-mRNA as a stable preformed di-snRNP complex, thereby bridging the 5' and 3' ends of the intron within the U12-dependent prespliceosome. To identify proteins contributing to di-snRNP formation and intron bridging, we investigated protein-protein and protein-RNA interactions between components of the U11/U12 snRNP. We demonstrate that the U11/U12-65K protein possesses dual binding activity, interacting directly with U12 snRNA via its C-terminal RRM and the U11-associated 59K protein via its N-terminal half. We provide evidence that, in contrast to the previously published U12 snRNA secondary structure model, the 3' half of U12 forms an extended stem-loop with a highly conserved seven-nucleotide loop and that the latter serves as the 65K binding site. Addition of an oligonucleotide comprising the 65K binding site to an in vitro splicing reaction inhibited U12-dependent, but not U2-dependent, pre-mRNA splicing. Taken together, these data suggest that U11/U12-65K and U11-59K contribute to di-snRNP formation and intron bridging in the minor prespliceosome.


Asunto(s)
ARN Nuclear Pequeño/genética , Ribonucleoproteínas Nucleares Pequeñas/metabolismo , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Animales , Ensayo de Cambio de Movilidad Electroforética , Evolución Molecular , Humanos , Intrones , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Unión Proteica , Ribonucleoproteínas Nucleares Pequeñas/genética , Homología de Secuencia de Aminoácido , Empalmosomas/genética , Empalmosomas/metabolismo
14.
Biochem J ; 383(Pt. 3): 419-28, 2004 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-15279620

RESUMEN

NusB is a prokaryotic transcription factor involved in antitermination processes, during which it interacts with the boxA portion of the mRNA nut site. Previous studies have shown that NusB exhibits an all-helical fold, and that the protein from Escherichia coli forms monomers, while Mycobacterium tuberculosis NusB is a dimer. The functional significance of NusB dimerization is unknown. We have determined five crystal structures of NusB from Thermotoga maritima. In three crystal forms the protein appeared monomeric, whereas the two other crystal forms contained assemblies, which resembled the M. tuberculosis dimers. In solution, T. maritima NusB could be cross-linked as dimers, but it migrated as a monomer in gel-filtration analyses, suggesting a monomer/dimer equilibrium with a preference for the monomer. Binding to boxA-like RNA sequences could be detected by gel-shift analyses and UV-induced cross-linking. An N-terminal arginine-rich sequence is a probable RNA binding site of the protein, exhibiting aromatic residues as potential stacking partners for the RNA bases. Anions located in various structures support the assignment of this RNA binding site. The proposed RNA binding region is hidden in the subunit interface of dimeric NusB proteins, such as NusB from M. tuberculosis, suggesting that such dimers have to undergo a considerable conformational change or dissociate for engagement with RNA. Therefore, in certain organisms, dimerization may be employed to package NusB in an inactive form until recruitment into antitermination complexes.


Asunto(s)
Thermotoga maritima/química , Factores de Transcripción/química , Secuencia de Aminoácidos/genética , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Sitios de Unión/genética , Clonación Molecular/métodos , Cristalización/métodos , Bases de Datos de Proteínas , Dimerización , Proteínas de Escherichia coli/química , Regulación de la Expresión Génica/fisiología , Modelos Moleculares , Datos de Secuencia Molecular , Mycobacterium tuberculosis/química , Péptidos/química , Filogenia , Pliegue de Proteína , Estructura Cuaternaria de Proteína , Estructura Terciaria de Proteína/genética , ARN Bacteriano/metabolismo , Regiones Terminadoras Genéticas/genética , Factores de Transcripción/biosíntesis , Factores de Transcripción/genética , Transcripción Genética/genética , Difracción de Rayos X/métodos
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