RESUMEN
Transcription infidelity (TI) is a mechanism that increases RNA and protein diversity. We found that single-base omissions (i.e., gaps) occurred at significantly higher rates in the RNA of highly allergenic legumes. Transcripts from peanut, soybean, sesame, and mite allergens contained a higher density of gaps than those of nonallergens. Allergen transcripts translate into proteins with a cationic carboxy terminus depleted in hydrophobic residues. In mice, recombinant TI variants of the peanut allergen Ara h 2, but not the canonical allergen itself, induced, without adjuvant, the production of anaphylactogenic specific IgE (sIgE), binding to linear epitopes on both canonical and TI segments of the TI variants. The removal of cationic proteins from bovine lactoserum markedly reduced its capacity to induce sIgE. In peanut-allergic children, the sIgE reactivity was directed toward both canonical and TI segments of Ara h 2 variants. We discovered 2 peanut allergens, which we believe to be previously unreported, because of their RNA-DNA divergence gap patterns and TI peptide amino acid composition. Finally, we showed that the sIgE of children with IgE-negative milk allergy targeted cationic proteins in lactoserum. We propose that it is not the canonical allergens, but their TI variants, that initiate sIgE isotype switching, while both canonical and TI variants elicit clinical allergic reactions.
Asunto(s)
Alérgenos/genética , Alérgenos/inmunología , Fabaceae/genética , Fabaceae/inmunología , Sistema de Lectura Ribosómico , Proteínas de Plantas/genética , Proteínas de Plantas/inmunología , Albuminas 2S de Plantas/genética , Albuminas 2S de Plantas/inmunología , Adolescente , Anafilaxia/etiología , Anafilaxia/inmunología , Animales , Antígenos de Plantas/genética , Antígenos de Plantas/inmunología , Arachis/genética , Arachis/inmunología , Bovinos , Niño , Preescolar , Femenino , Variación Genética , Humanos , Sueros Inmunes/genética , Sueros Inmunes/inmunología , Inmunoglobulina E/biosíntesis , Masculino , Ratones , Ratones Endogámicos BALB C , Hipersensibilidad a la Leche/inmunología , Hipersensibilidad al Cacahuete/etiología , Hipersensibilidad al Cacahuete/inmunología , Phaseolus/genética , Phaseolus/inmunología , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Glycine max/genética , Glycine max/inmunología , Transcripción GenéticaRESUMEN
No specific biomarkers for prognostication or evaluation of tumour load in melanoma have been reported to our knowledge. MicroRNAs (miRNAs) are strongly implicated in oncogenesis and tumour progression, and their circulating forms have been studied as potential biomarkers in oncology. The aim of this prospective study was to identify a melanoma-specific profile of plasma miRNAs. A screening phase, using RNA microarray, was conducted on plasma from 14 patients with metastatic melanoma and 5 healthy subjects. Selected miRNAs were analysed by RTqPCR in 2 independent training and validation cohorts including, respectively, 29 and 31 patients and 16 and 43 control subjects. A profile of 2 miRNAs (miR-1246 and miR-185) significantly associated with metastatic melanoma with a sensitivity of 90.5% and a specificity of 89.1% was identified. This plasma miRNA profile may become an accurate non-invasive biomarker for melanoma.
Asunto(s)
Biomarcadores de Tumor/sangre , Perfilación de la Expresión Génica , Melanoma/sangre , MicroARNs/sangre , Neoplasias Cutáneas/sangre , Biomarcadores de Tumor/genética , Estudios de Casos y Controles , Perfilación de la Expresión Génica/métodos , Humanos , Melanoma/genética , Melanoma/secundario , MicroARNs/genética , Análisis de Secuencia por Matrices de Oligonucleótidos , Valor Predictivo de las Pruebas , Pronóstico , Estudios Prospectivos , Reproducibilidad de los Resultados , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patologíaRESUMEN
The Périgord black truffle (Tuber melanosporum Vittad.) and the Piedmont white truffle dominate today's truffle market. The hypogeous fruiting body of T. melanosporum is a gastronomic delicacy produced by an ectomycorrhizal symbiont endemic to calcareous soils in southern Europe. The worldwide demand for this truffle has fuelled intense efforts at cultivation. Identification of processes that condition and trigger fruit body and symbiosis formation, ultimately leading to efficient crop production, will be facilitated by a thorough analysis of truffle genomic traits. In the ectomycorrhizal Laccaria bicolor, the expansion of gene families may have acted as a 'symbiosis toolbox'. This feature may however reflect evolution of this particular taxon and not a general trait shared by all ectomycorrhizal species. To get a better understanding of the biology and evolution of the ectomycorrhizal symbiosis, we report here the sequence of the haploid genome of T. melanosporum, which at approximately 125 megabases is the largest and most complex fungal genome sequenced so far. This expansion results from a proliferation of transposable elements accounting for approximately 58% of the genome. In contrast, this genome only contains approximately 7,500 protein-coding genes with very rare multigene families. It lacks large sets of carbohydrate cleaving enzymes, but a few of them involved in degradation of plant cell walls are induced in symbiotic tissues. The latter feature and the upregulation of genes encoding for lipases and multicopper oxidases suggest that T. melanosporum degrades its host cell walls during colonization. Symbiosis induces an increased expression of carbohydrate and amino acid transporters in both L. bicolor and T. melanosporum, but the comparison of genomic traits in the two ectomycorrhizal fungi showed that genetic predispositions for symbiosis-'the symbiosis toolbox'-evolved along different ways in ascomycetes and basidiomycetes.
