RESUMEN
High throughput sequencing technologies have revolutionized the potential to reconcile incongruence between gene and species trees, and numerous approaches have been developed to take advantage of these advances. Genotyping-by-sequencing is becoming a regular tool for gathering phylogenetic data, yet comprehensive evaluations of phylogenetic methods using these data are sparse. Here we use multiple phylogenetic and population genetic methods for genotyping-by-sequencing data to assess species relationships in a group of forest insect pests, the spruce budworm (Choristoneura fumiferana) species complex. With few exceptions, all methods agree on the same relationships, most notably placing C. pinus as basal to the remainder of the group, rather than C. fumiferana as previously suggested. We found strong support for the monophyly of C. pinus, C. fumiferana, and C. retiniana, but more ambiguous relationships and signatures of introgression in a clade of western lineages, including C. carnana, C. lambertiana, C. occidentalis occidentalis, C. occidentalis biennis, and C. orae. This represents the most taxonomically comprehensive genomic treatment of the spruce budworm species group, which is further supported by the broad agreement among multiple methodologies.
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Genoma de los Insectos , Mariposas Nocturnas/genética , Filogenia , Polimorfismo de Nucleótido Simple/genética , Animales , Análisis Discriminante , Especiación Genética , Genética de Población , Genotipo , Geografía , América del Norte , Análisis de Componente Principal , Análisis de Secuencia de ADN , Especificidad de la Especie , Estados UnidosRESUMEN
This dataset provides growth form classifications for 67,413 vascular plant species from North, Central, and South America. The data used to determine growth form were compiled from five major integrated sources and two original publications: the Botanical Information and Ecology Network (BIEN), the Plant Trait Database (TRY), the SALVIAS database, the USDA PLANTS database, Missouri Botanical Garden's Tropicos database, Wright (2010), and Boyle (1996). We defined nine plant growth forms based on woodiness (woody or non-woody), shoot structure (self-supporting or not self-supporting), and root traits (rooted in soil, not rooted in soil, parasitic or aquatic): Epiphyte, Liana, Vine, Herb, Shrub, Tree, Parasite, or Aquatic. Species with multiple growth form classifications were assigned the growth form classification agreed upon by the majority (>2/3) of sources. Species with ambiguous or otherwise not interpretable growth form assignments were excluded from the final dataset but are made available with the original data. Comparisons with independent estimates of species richness for the Western hemisphere suggest that our final dataset includes the majority of New World vascular plant species. Coverage is likely more complete for temperate than for tropical species. In addition, aquatic species are likely under-represented. Nonetheless, this dataset represents the largest compilation of plant growth forms published to date, and should contribute to new insights across a broad range of research in systematics, ecology, biogeography, conservation, and global change science.
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Desarrollo de la Planta , Plantas/clasificación , América Central , Demografía , América del Norte , América del Sur , Especificidad de la EspecieRESUMEN
There is an ever increasing need to develop new tools to aid in the diagnosis and monitoring of human diseases. Such tools will ultimately reduce the cost of healthcare by identifying disease states more quickly and cheaply than current practices. One method showing promise is the analysis of gas-phase biomarkers from human breath, urine, sweat and stool that reflect bodily metabolism. Analysis of these volatiles by GC MS requires specialised infra-structure and staff, making it unsuitable for a clinical setting. Point of care sensor based technologies such as eNoses often suffer from stability and sensitivity issues. Field-Asymmetric Ion Mobility Spectrometry (FAIMS) has potential to fulfil this clinical need. In this paper we review the medical need, the technology, sampling methods and medical evidence thus far. We conclude with reflecting on future developmental steps necessary to bring the device into medical practice.
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Técnicas y Procedimientos Diagnósticos , Gases/química , Espectrometría de Masas/métodos , Técnicas y Procedimientos Diagnósticos/instrumentación , Humanos , Espectrometría de Masas/instrumentaciónRESUMEN
OBJECTIVES: Ireland has the highest rate of vancomycin-resistant Enterococcus faecium (VREfm) isolated from blood of nosocomial patients in Europe, which rose from 33% (110/330) in 2007 to 45% (178/392) in 2012. No other European country had a VREfm rate from blood cultures of >25%. Our aim was to elucidate the reasons for this significantly higher rate in Ireland. METHODS: The epidemiology and molecular typing of VRE from bloodstream infections (BSIs) was examined in a tertiary care referral hospital and isolates were compared with those from other tertiary care referral centres in the region. RESULTS: The most common source of VRE BSIs was intra-abdominal sepsis, followed by line-related infection and febrile neutropenia. Most of the isolates were positive for vanA; 52% (43/83) possessed the esp gene and 12% (10/83) possessed the hyl gene. Genotyping by SmaI macrorestriction analysis (PFGE) of isolates revealed clonal relatedness between bloodstream isolates and environmental isolates. VRE BSI isolates from two other tertiary care hospitals in the Dublin region showed relatedness by PFGE analysis. MLST revealed four STs (ST17, ST18, ST78 and ST203), all belonging to the clonal complex of hospital-associated strains. CONCLUSIONS: Irish VRE BSI isolates have virulence factor profiles as previously reported from Europe. Typing analysis shows the spread of individual clones within the hospital and between regional tertiary care hospitals. Apart from transmission of VRE within the hospital and transfer of colonized patients between Irish hospitals, no other explanation for the persistently high VREfm BSI rate in Ireland has been found.
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Bacteriemia , Infección Hospitalaria , Enterococcus faecium/efectos de los fármacos , Enterococcus faecium/genética , Infecciones por Bacterias Grampositivas/epidemiología , Infecciones por Bacterias Grampositivas/microbiología , Centros de Atención Terciaria , Resistencia a la Vancomicina , Adulto , Anciano , Anciano de 80 o más Años , Análisis por Conglomerados , Enterococcus faecium/clasificación , Femenino , Infecciones por Bacterias Grampositivas/mortalidad , Humanos , Irlanda/epidemiología , Masculino , Persona de Mediana Edad , Tipificación Molecular , Adulto JovenRESUMEN
BACKGROUND: Recurrent Clostridium difficile infection (CDI) represents a significant healthcare challenge. Patients may suffer multiple episodes of CDI with the index strain (relapse) or become infected by another strain acquired nosocomially (reinfection). AIM: We aimed to characterize C. difficile isolates causing recurrent CDI at a tertiary referral hospital by whole-genome sequencing (WGS) to assess strain similarities at the highest level of genetic resolution and accurately detect relapse, reinfection, and putative strain transmission events. METHODS: An 18-month prospective study of recurrent CDI was undertaken. Clostridium difficile was cultured from stool samples collected longitudinally from any patients suffering ≥2 clinically defined CDI episodes. Patient demographics and clinical data were recorded, and strain relatedness investigated by both polymerase chain reaction (PCR)-based ribotyping and WGS. FINDINGS: Nineteen patients were identified with ≥2 clinically defined CDI episodes who cumulatively suffered 39 recurring CDI episodes (58 total episodes). Patients had a median length of stay (LOS) of 144 days and experienced between two and seven CDI episodes. Ribotyping indicated 27 apparent same-strain relapses, five reinfections and the predominance of ribotypes 078 (ST-11) and 020 (ST-2). WGS allowed characterization of relapse with increased certainty and identified emergent within-strain single nucleotide variants (SNVs) with potential functional impact on diverse genes. Shared ribotypes among 14 patients with recurrent CDI suggested 10 possible patient-to-patient transmission events. However, WGS revealed greater diversity at the sub-ribotype level, excluding all but four transmission events. CONCLUSION: WGS exhibits several advantages over PCR-based ribotyping in terms of its ability to distinguish relapse from reinfection, to identify patient-to-patient transmission events, and to exact fine structure characterization of recurrent CDI epidemiology. This offers the potential for more focused infection prevention strategies to eliminate strain transmission among patients with recurrent CDI.
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Antibacterianos/uso terapéutico , Clostridioides difficile/genética , Clostridioides difficile/aislamiento & purificación , Infecciones por Clostridium/tratamiento farmacológico , Infecciones por Clostridium/transmisión , Ribotipificación , Adulto , Anciano , Anciano de 80 o más Años , Infecciones por Clostridium/epidemiología , Femenino , Genoma , Humanos , Irlanda , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Estudios Prospectivos , RecurrenciaRESUMEN
OBJECTIVE: To determine risk of Down syndrome (DS) in multiple relative to singleton pregnancies, and compare prenatal diagnosis rates and pregnancy outcome. DESIGN: Population-based prevalence study based on EUROCAT congenital anomaly registries. SETTING: Eight European countries. POPULATION: 14.8 million births 1990-2009; 2.89% multiple births. METHODS: DS cases included livebirths, fetal deaths from 20 weeks, and terminations of pregnancy for fetal anomaly (TOPFA). Zygosity is inferred from like/unlike sex for birth denominators, and from concordance for DS cases. MAIN OUTCOME MEASURES: Relative risk (RR) of DS per fetus/baby from multiple versus singleton pregnancies and per pregnancy in monozygotic/dizygotic versus singleton pregnancies. Proportion of prenatally diagnosed and pregnancy outcome. STATISTICAL ANALYSIS: Poisson and logistic regression stratified for maternal age, country and time. RESULTS: Overall, the adjusted (adj) RR of DS for fetus/babies from multiple versus singleton pregnancies was 0.58 (95% CI 0.53-0.62), similar for all maternal ages except for mothers over 44, for whom it was considerably lower. In 8.7% of twin pairs affected by DS, both co-twins were diagnosed with the condition. The adjRR of DS for monozygotic versus singleton pregnancies was 0.34 (95% CI 0.25-0.44) and for dizygotic versus singleton pregnancies 1.34 (95% CI 1.23-1.46). DS fetuses from multiple births were less likely to be prenatally diagnosed than singletons (adjOR 0.62 [95% CI 0.50-0.78]) and following diagnosis less likely to be TOPFA (adjOR 0.40 [95% CI 0.27-0.59]). CONCLUSIONS: The risk of DS per fetus/baby is lower in multiple than singleton pregnancies. These estimates can be used for genetic counselling and prenatal screening.
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Síndrome de Down/diagnóstico , Síndrome de Down/epidemiología , Embarazo Múltiple , Diagnóstico Prenatal , Adulto , Europa (Continente)/epidemiología , Femenino , Humanos , Edad Materna , Persona de Mediana Edad , Embarazo , Resultado del Embarazo , Prevalencia , Riesgo , Medición de Riesgo , Gemelos Dicigóticos , Gemelos Monocigóticos , Adulto JovenRESUMEN
OBJECTIVE: To assess the public health consequences of the rise in multiple births with respect to congenital anomalies. DESIGN: Descriptive epidemiological analysis of data from population-based congenital anomaly registries. SETTING: Fourteen European countries. POPULATION: A total of 5.4 million births 1984-2007, of which 3% were multiple births. METHODS: Cases of congenital anomaly included live births, fetal deaths from 20 weeks of gestation and terminations of pregnancy for fetal anomaly. MAIN OUTCOME MEASURES: Prevalence rates per 10,000 births and relative risk of congenital anomaly in multiple versus singleton births (1984-2007); proportion prenatally diagnosed, proportion by pregnancy outcome (2000-07). Proportion of pairs where both co-twins were cases. RESULTS: Prevalence of congenital anomalies from multiple births increased from 5.9 (1984-87) to 10.7 per 10,000 births (2004-07). Relative risk of nonchromosomal anomaly in multiple births was 1.35 (95% CI 1.31-1.39), increasing over time, and of chromosomal anomalies was 0.72 (95% CI 0.65-0.80), decreasing over time. In 11.4% of affected twin pairs both babies had congenital anomalies (2000-07). The prenatal diagnosis rate was similar for multiple and singleton pregnancies. Cases from multiple pregnancies were less likely to be terminations of pregnancy for fetal anomaly, odds ratio 0.41 (95% CI 0.35-0.48) and more likely to be stillbirths and neonatal deaths. CONCLUSIONS: The increase in babies who are both from a multiple pregnancy and affected by a congenital anomaly has implications for prenatal and postnatal service provision. The contribution of assisted reproductive technologies to the increase in risk needs further research. The deficit of chromosomal anomalies among multiple births has relevance for prenatal risk counselling.
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Anomalías Congénitas/epidemiología , Muerte Fetal/epidemiología , Progenie de Nacimiento Múltiple , Complicaciones del Embarazo/epidemiología , Mortinato/epidemiología , Europa (Continente)/epidemiología , Femenino , Humanos , Embarazo , Resultado del Embarazo , Diagnóstico Prenatal , Prevalencia , Sistema de Registros , RiesgoRESUMEN
Genomic DNA sequences and other genomic resources are essential towards the elucidation of the genomic bases of adaptive divergence and reproductive isolation. Here, we describe the construction, characterization and screening of a nonarrayed BAC library for lake whitefish (Coregonus clupeaformis). We then show how the combined use of BAC library screening and next-generation sequencing can lead to efficient full-length assembly of candidate genes. The lake whitefish BAC library consists of 181,050 clones derived from a single heterozygous fish. The mean insert size is 92 Kb, representing 5.2 haploid genome equivalents. Ten BAC clones were isolated following a quantitative real-time PCR screening approach that targeted five previously identified candidate genes. Sequencing of these clones on a 454 GS FLX system yielded 178,000 reads with a mean length of 358 bp, for a total of 63.8 Mb. De novo assembly and annotation then allowed retrieval of contigs corresponding to each candidate gene, which also contained up- and/or downstream noncoding sequences. These results suggest that the lake whitefish BAC library combined with next-generation sequencing technologies will be key resources to achieve a better understanding of both adaptive divergence and reproductive isolation in lake whitefish species pairs as well as salmonid evolution in general.
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Evolución Molecular , Biblioteca de Genes , Especiación Genética , Salmonidae/genética , Adaptación Biológica , Animales , Cromosomas Artificiales Bacterianos , ADN/química , ADN/genética , Vectores Genéticos , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADNRESUMEN
Rosiglitazone, a peroxisome proliferator-activated receptor γ (PPARγ) agonist of the thiazolidinedione class, is a major insulin-sensitizing drug widely used to treat type-2 diabetes. Rosiglitazone causes myocardial hypertrophy in rodents and increases the risk of cardiac events in man. To better characterize its cardiac effects, male Wistar rats were orally administered 0, 10 or 80 mg/kg/day rosiglitazone. Myocardial gene expression profiling, hematology, histopathology and clinical chemistry, including measurement of serum cardiac troponin (cTn) I concentration with the ultrasensitive assay, were evaluated after 6 and 24h and 7 and 14 days of dosing. Heart weight was increased 10% after 7 days and 16% after 14 days of dosing at 80 mg/kg/day in the absence of microscopic changes. At the transcriptomic level, the number of differentially expressed probes was small: it was most at 24h in rats given 80 mg/kg rosiglitazone with 356 differentially regulated probes (fold change >1.3 fold, p<0.05). Also, gene categories typically associated with myocardial damage were not over-represented. Most importantly, serum cTnI concentrations in 5/9 rats after 7 days of dosing at 80 mg/kg/day were above the upper limit of serum cTnI concentration. cTnI concentrations after 14 days of dosing were similar between rats given the vehicle and rosiglitazone at 80 mg/kg. This is the first study to detect increases of serum cTnI concentrations in rats administered rosiglitazone. In light of reported cardiac events in patients chronically dosed with PPARγ agonists, our results support serum cTnI concentrations as an early biomarker of cardiac liability.
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Corazón/efectos de los fármacos , Hipoglucemiantes/toxicidad , PPAR gamma/agonistas , Tiazolidinedionas/toxicidad , Troponina I/sangre , Animales , Perfilación de la Expresión Génica , Masculino , Miocardio/patología , Tamaño de los Órganos/efectos de los fármacos , Ratas , Ratas Wistar , RosiglitazonaRESUMEN
In this study, we compared interactions of two Melampsora foliar rust species with poplar, which resulted in either limited or abundant pathogen proliferation. In the pathosystem exhibiting limited pathogen growth, a defence response was observed after invasion of poplar leaf tissues by the biotroph, with late and clear production of reactive oxygen species (ROS) and other products. Characterisation of the histological, biochemical and transcriptional events occurring in both pathosystems showed striking similarity with components of plant defence reactions observed during qualitative resistance. Key components associated with development of an active defence response, such as up-regulation of pathogenesis-related (PR) genes, were observed during infection. Moreover, the time course and strength of gene induction appear to be critical determinants for the outcome of the tree-pathogen interaction. This work provides basic biochemical characterisation and expression data for the study of so-called partial resistance in the poplar-rust pathosystem, which is also applicable to other plant-pathogen interactions resulting in quantitative disease resistance.
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Basidiomycota/fisiología , Interacciones Huésped-Patógeno , Enfermedades de las Plantas/inmunología , Populus/microbiología , Regulación de la Expresión Génica de las Plantas , Inmunidad Innata , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Hojas de la Planta/inmunología , Hojas de la Planta/microbiología , Populus/genética , Populus/inmunología , ARN de Planta/genética , Especies Reactivas de Oxígeno/metabolismoAsunto(s)
Clostridioides difficile/aislamiento & purificación , Enterocolitis Seudomembranosa/diagnóstico , Índice de Severidad de la Enfermedad , Toxinas Bacterianas/aislamiento & purificación , Infecciones por Clostridium/complicaciones , Enterotoxinas/aislamiento & purificación , Humanos , Hipoalbuminemia/complicaciones , Leucocitosis/complicaciones , Valor Predictivo de las Pruebas , Factores de Riesgo , Urea/sangreRESUMEN
BACKGROUND/AIMS: Glucocorticoids have an important role in the regulation of the immune system, and alterations in glucocorticoid signaling may have an impact on the pathophysiology of autoimmune and inflammatory disorders. Because polymorphisms of the glucocorticoid receptor (GR) gene, including the N363S, ER22/23EK, A3669G and BclI variants were found to influence glucocorticoid signalling, we examined whether these polymorphisms could be associated with the development or clinical manifestations of Graves ophthalmopathy (GO). METHODS: The carrier and allelic frequencies of the N363S, ER22/23EK, A3669G, and BclI polymorphisms of the GR were determined in 95 Hungarian outpatients with GO and 160 healthy controls. RESULTS: No significant changes were found in carrier frequencies of the four polymorphisms between GO patients and healthy controls. However, when GO patients were divided into two subgroups (American Thyroid Association Committee, ATA I-II vs ATA III or greater), the frequency of the polymorphic BclI allele was significantly higher in patients with ATA I-II compared with those with ATA III or more (p = 0.009). CONCLUSION: The significant association between the frequency of the polymorphic BclI allele and ATA stage distribution suggests that this polymorphism of the GR gene may affect clinical manifestations of GO, presumably due to an increased signaling of endogenous glucocorticoids.
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Oftalmopatía de Graves/genética , Polimorfismo Genético , Receptores de Glucocorticoides/genética , Adulto , Anciano , Femenino , Frecuencia de los Genes , Oftalmopatía de Graves/patología , Heterocigoto , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la EnfermedadRESUMEN
Most acute myeloid leukaemia (AML) patients lack human leucocyte antigen-identical sibling donors for transplantation. Autotransplants and unrelated donor (URD) transplants are therapeutic options. To compare autologous versus URD transplantation for AML in first (CR1) or second complete remission (CR2), we studied the outcomes of 668 autotransplants were compared with 476 URD transplants reported to the Center for International Blood and Marrow Transplant Research. Proportional hazards regression adjusted for differences in prognostic variables. In multivariate analyses transplant-related mortality (TRM) was significantly higher and relapse lower with URD transplantation. Adjusted 3-year survival probabilities were: in CR1 57 (53-61)% with autotransplants and 44 (37-51)% URD (P = 0.002), in CR2 46 (39-53)% and 33 (28-38)% respectively (P = 0.006). Adjusted 3-year leukaemia-free survival (LFS) probabilities were: CR1 53 (48-57)% with autotransplants and 43 (36-50)% with URD (P = 0.021), CR2 39 (32-46)% and 33 (27-38)% respectively (P = 0.169). Both autologous and URD transplantation produced prolonged LFS. High TRM offsets the superior antileukaemia effect of URD transplantation. This retrospective, observational database study showed that autotransplantation, in general, offered higher 3-year survival for AML patients in CR1 and CR2. Cytogenetics, however, were known in only two-thirds of patients and treatment bias cannot be eliminated.
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Trasplante de Médula Ósea/métodos , Trasplante de Células Madre Hematopoyéticas/métodos , Leucemia Mieloide/cirugía , Enfermedad Aguda , Adolescente , Adulto , Niño , Femenino , Prueba de Histocompatibilidad/métodos , Humanos , Leucemia Mieloide/mortalidad , Masculino , Recurrencia Local de Neoplasia , Estudios Retrospectivos , Análisis de Supervivencia , Trasplante Autólogo/métodos , Trasplante Homólogo/métodos , Resultado del TratamientoRESUMEN
A high level of adherence to highly active antiretroviral therapy (HAART) is essential to minimize the risk of treatment failure and HIV disease progression. This cohort study evaluated the prevalence and predictors of long-term adherence with first-line HAART in a hospital-based unselected sample of HIV patients from central Italy, and examined the association between adherence and virological response or relapse. Between July 1996 and June 2004, 171 patients (67.3% males; mean age, 41.2 years) were followed for at least 24 weeks and up to 8 years. Adherence was measured by patient self-reports and confirmed using pharmacy records. The prevalence of high-level adherence (>or=90%) at 6 months was 88.3%; slightly less than 80% at 12 months. The incidence of adherence failure in the sample remained fairly stable until 24 months of follow-up, then it declined about 5% every 6 months. Cox analysis showed that compared to single/separated patients, homeless and married persons were, respectively, 1.95 times more likely and two times less likely to experience adherence failure (p < 0.05). The adjusted risk of adherence failure among patients who did not suffer drug-related toxicity was 0.57 (p < 0.05). Medication adherence was significantly associated with shorter time to virological response and longer time to relapse. Adherents were 1.69 times more likely to achieve viral suppression and nine times less likely to experience relapse than nonadherents (p < 0.01). Efforts at improving adherence should be prolonged for at least 24 months. A protective role of marriage for adherence failure is promising but requires confirmation in further research, that should also clarify the exact mechanisms determining the association.
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Terapia Antirretroviral Altamente Activa , Infecciones por VIH/tratamiento farmacológico , VIH-1/efectos de los fármacos , Hospitales , Cooperación del Paciente , Adulto , Estudios de Cohortes , Femenino , Infecciones por VIH/virología , VIH-1/fisiología , Humanos , Italia , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Prevalencia , ARN Viral/sangre , Recurrencia , Factores de TiempoRESUMEN
Here we report the identification of a new insulin-like growth factor binding protein homologue, provisionally designated insulin-like growth factor binding related protein-4 (IGFBP-rP4). IGFBP-rP4 was found to be most closely related to IGFBP-7 with 52% amino acid homology and 43% amino acid identity, and shares a similar domain structure. Semi-quantitative RT-PCR expression analysis demonstrated a pattern of downregulation of this gene in multiple tumor samples including lung and colon cancer, compared to matched adjacent normal tissue. Western blotting revealed a protein of approximately 38kDa expressed in both the cell pellet and secreted into the supernatant of transiently transfected Cos-7 cells. Cos-7 supernatants containing IGFBP-RP4 protein were observed to suppress the growth of HeLa cells in culture compared to vector controls. IGFBP-RP4 directly transiently transfected into HeLa cells also further confirmed the growth suppressive properties of this protein. Together these data suggest that IGFBP-RP4 may be a novel putative tumor suppressor protein.
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Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/genética , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/fisiología , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/fisiología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Células COS , Chlorocebus aethiops , Clonación Molecular , Células HeLa , Humanos , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/clasificación , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Datos de Secuencia Molecular , Filogenia , Proteínas Supresoras de Tumor/metabolismoRESUMEN
The potato pathogenesis-related gene PR-10a is transcriptionally activated in response to pathogen infection or elicitor treatment. Characterization of the cis-acting elements of the PR-10a promoter revealed the presence of a silencing element between residues -52 and -27 that contributes to transcriptional regulation. In this study, we have isolated a silencing element binding factor (SEBF) from potato tuber nuclei that binds to the coding strand of the silencing element in a sequence-specific manner. The consensus binding site of SEBF, PyTGTCNC, is present in a number of PR genes and shows striking similarity to the auxin response element. Mutational analysis of the PR-10a promoter revealed an inverse correlation between the in vitro binding of SEBF and the expression of PR-10a. SEBF was purified to homogeneity from potato tubers, and sequencing of the N terminus of the protein led to the isolation of a cDNA clone. Sequence analysis revealed that SEBF is homologous with chloroplast RNA binding proteins that possess consensus sequence-type RNA binding domains characteristic of heterogeneous nuclear ribonucleoproteins (hnRNPs). Overexpression of SEBF in protoplasts repressed the activity of a PR-10a reporter construct in a silencing element-dependent manner, confirming the role of SEBF as a transcriptional repressor.