RESUMEN
DEAD-box proteins comprise a family of ATP-dependent RNA helicases involved in several aspects of RNA metabolism. Here we report the characterization of the human DEAD-box RNA helicase DDX26. The gene is composed of 14 exons distributed over an extension of 8,123 bp of genomic sequence and encodes a transcript of 1.8 kb that is expressed in all tissues evaluated. The predicted amino acid sequence shows a high similarity to a yeast DEAD-box RNA helicase (Dbp9b) involved in ribosome biogenesis. The new helicase maps to 7p12, a region of frequent chromosome amplifications in glioblastomas involving the epidermal growth factor receptor (EGFR) gene. Nevertheless, co-amplification of DDX26 with EGFR was not detected in nine tumors analyzed.
Asunto(s)
Cromosomas Humanos Par 7/genética , ARN Helicasas/química , ARN Helicasas/genética , Proteínas Supresoras de Tumor , Secuencia de Aminoácidos , Animales , Candida/genética , Secuencia Conservada , Drosophila/genética , Amplificación de Genes , Expresión Génica , Genes erbB-1 , Glioblastoma/genética , Humanos , Datos de Secuencia Molecular , Proteínas de Unión al ARN , Proteínas Ribosómicas , Células Tumorales Cultivadas , Levaduras/genéticaRESUMEN
DEAD-box proteins comprise a family of ATP-dependent RNA helicases involved in several aspects of RNA metabolism. Here we report the characterization of the human DEAD-box RNA helicase DDX26. The gene is composed of 14 exons distributed over an extension of 8,123 bp of genomic sequence and encodes a transcript of 1.8 kb that is expressed in all tissues evaluated. The predicted amino acid sequence shows a high similarity to a yeast DEAD-box RNA helicase (Dbp9b) involved in ribosome biogenesis. The new helicase maps to 7p12, a region of frequent chromosome amplifications in glioblastomas involving the epidermal growth factor receptor (EGFR) gene. Nevertheless, co-amplification of DDX26 with EGFR was not detected in nine tumors analyzed
Asunto(s)
Animales , Humanos , Cromosomas Humanos Par 7 , ARN Helicasas , Secuencia de Aminoácidos , Candida , Secuencia Conservada , Drosophila , Expresión Génica , Genes erbB-1 , Glioblastoma , Datos de Secuencia Molecular , Células Tumorales Cultivadas , LevadurasRESUMEN
A series of eight microsatellite loci were assayed for both loss of heterozygosity and new mutated alleles in 91 head and neck squamous cell carcinomas. In 58 cases, alterations were detected and used as markers for assaying the presence of circulating tumor-derived DNA in the patients' plasma. This was unambiguously detected in 17 cases. The probability of detecting circulating DNA was independent of tumor stage and was found to be present even in some individuals with stage I tumors. The presence of such DNA, however, could not be correlated with disease outcome or other significant clinical parameters, suggesting that it has no prognostic significance. The results indicate that circulating tumor-derived DNA could be used as a means of early diagnosis of head and neck tumors.
Asunto(s)
Biomarcadores de Tumor/sangre , Carcinoma de Células Escamosas/diagnóstico , ADN de Neoplasias/sangre , Neoplasias de Cabeza y Cuello/diagnóstico , Alelos , Carcinoma de Células Escamosas/sangre , Carcinoma de Células Escamosas/genética , Neoplasias de Cabeza y Cuello/sangre , Neoplasias de Cabeza y Cuello/genética , Humanos , Pérdida de Heterocigocidad , Repeticiones de MicrosatéliteRESUMEN
Microsatellite allele losses are characteristic features of head and neck squamous cell carcinoma and can be used as molecular markers for malignancy. We have investigated the detection of microsatellite allele loss in mouth washes and lesions brushings from 19 patients with squamous cell carcinoma of the oral cavity and oropharynx as a means of tumour detection. In 84% of the analysed cases, allele loss previously identified in the tumour of these patients, was detected in these easily obtained specimens. No alterations were found in material derived from 10 healthy individuals. Success of detection was independent of tumour stage, suggesting that this approach may be useful for early diagnosis as well as for follow-up.
Asunto(s)
Carcinoma de Células Escamosas/diagnóstico , Repeticiones de Microsatélite , Neoplasias de la Boca/diagnóstico , Neoplasias Orofaríngeas/diagnóstico , Biomarcadores de Tumor/análisis , Biomarcadores de Tumor/genética , Carcinoma de Células Escamosas/genética , Estudios de Casos y Controles , Humanos , Pérdida de Heterocigocidad , Neoplasias de la Boca/genética , Neoplasias Orofaríngeas/genética , Saliva/química , Manejo de Especímenes/métodosRESUMEN
The intermediate hosts of S. mansoni in South America, B. glabrata, B. tenagophila, and B. straminea, were identified by restriction fragment length polymorphism (RFLP) analysis of the internal transcribed spacer region of the rRNA gene. The restriction patterns obtained with DdeI were the most informative of the eight enzymes that were tried. The RFLP profiles obtained using this enzyme are highly distinctive and exhibit low levels of intraspecific polymorphism even between specimens collected from diverse regions of Brazil, Argentine, Paraguay, and Uruguay. The method proved useful for the identification of DNA extracted from eggs, permitting species identification while preserving the living adult specimens for further studies.
Asunto(s)
Biomphalaria/clasificación , ADN Ribosómico/análisis , ARN Ribosómico/genética , Schistosoma mansoni/fisiología , Animales , Biomphalaria/genética , Biomphalaria/parasitología , Brasil , ADN Ribosómico/química , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Reproducibilidad de los Resultados , Mapeo RestrictivoRESUMEN
Studies based on shell or reproductive organ morphology and genetic considerations suggest extensive intraspecific variation in Biomphalaria snails. The high variability at the morphological and genetic levels, as well as the small size of some specimens and similarities between species complicate the correct identification of these snails. Here we review our work using methods based on polymerase chain reaction (PCR) amplification for analysis of genetic variation and identification of Biomphalaria snails from Brazil, Argentina, Uruguay and Paraguay. Arbitrarily primed-PCR revealed that the genome of B. glabrata exhibits a remarkable degree of intraspecific polymorphism. Low stringency-PCR using primers for 18S rRNA permitted the identification of B. glabrata, B. tenagophila and B. occidentalis. The study of individuals obtained from geographically distinct populations exhibits significant intraspecific DNA polymorphism, however, specimens from the same species, exhibit some species specific LSPs. We also showed that PCR-restriction fragment of length polymorphism of the internal transcribed spacer region of Biomphalaria rDNA, using Ddel permits the differentiation of the three intermediate hosts of Schistosoma mansoni. the molecular biological techniques used in our studies are very useful for the generation of new knowledge concerning the systematics and population genetics of Biomphalaria snails.
Asunto(s)
Biomphalaria/genética , Biomphalaria/parasitología , Variación Genética/genética , Esquistosomiasis mansoni , Animales , Argentina , Biomphalaria/clasificación , Brasil , Paraguay , UruguayRESUMEN
Human tumors exhibit two fundamentally important characteristics, extensive genetic alteration and clonality. Although it is still unclear to what extent tumors have an elevated mutational burden as compared with normal tissue, their clonality results in their ready detection. Thus, assaying tissues for clonal alterations at frequently mutated microsatellite loci represents a viable approach to cancer diagnosis. The most remarkable extension of this concept is that not only can cancer cells be detected in biological samples, but tumor DNA can also be directly detected in the serum or plasma of patients with some forms of cancer. This recent finding is currently being explored but may represent an important contribution to future diagnostic strategies.