Mécanismes et conséquences des mutations

L’identification des mutations à l’origine de maladies génétiques chez l’homme a pris ces dernières années un essor considérable. Il est devenu possible d’établir le spectre des mutations délétères pour une maladie génétique donnée, et des bases de données internationales sont aujourd’hui accessibles via le réseau Internet. Le diagnostic génotypique des maladies héréditaires occupe actuellement une place prépondérante en matière de conseil génétique et de diagnostic prénatal. La connaissance du type de mutation délétère et des mécanismes en cause est essentielle pour déterminer la stratégie de diagnostic moléculaire adaptée à chaque situation. Cet article a pour objectif de présenter les différents types de mutations responsables de maladies génétiques (substitutions nucléotidiques, délétions ou insertions de petite taille, mutations dynamiques, grands remaniements…) et de récapituler les connaissances actuelles concernant les mécanismes moléculaires à l’origine de ces mutations. Leurs conséquences sur l’expression du gène (transcription et maturation du transcrit) et sur la fonction de la protéine sont également abordées dans cet article.The identification of mutations leading to human genetic diseases has grown into an intensive research field during the last few years. Through novel DNA analysis progress, it is now possible to determine the mutational spectrum for a given genetic disease and international databases are now available online. Genetic diagnosis of hereditary diseases has become an essential tool in genetic counselling and prenatal diagnosis. The knowledge of the deleterious mutation type and the molecular associated mechanism is fundamental in order to devise the optimal molecular diagnosis strategy. This review aims to present the various mutation categories involved in genetic diseases (single base-pair substitutions, small deletions or insertions, dynamic mutations, gross DNA lesions…) and to summarize our current knowledge about the main molecular mechanisms responsible for these mutations. Their deleterious consequences on gene expression, including transcription and transcript maturation, and protein loss or gain of function are also discussed in this review

Molecular profiling of malignant peripheral nerve sheath tumors associated with neurofibromatosis type 1, based on large-scale real-time RT-PCR

BACKGROUND: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with a complex range of clinical symptoms. The hallmark of NF1 is the onset of heterogeneous (dermal or plexiform) benign neurofibromas. Plexiform neurofibromas can give rise to malignant peripheral nerve sheath tumors (MPNSTs), and the underlying molecular mechanisms are largely unknown. RESULTS: To obtain further insight into the molecular pathogenesis of MPNSTs, we used real-time quantitative RT-PCR to quantify the mRNA expression of 489 selected genes in MPNSTs, in comparison with plexiform neurofibromas. The expression of 28 (5.7%) of the 489 genes was significantly different between MPNSTs and plexiform neurofibromas; 16 genes were upregulated and 12 were downregulated in MPNSTs. The altered genes were mainly involved in cell proliferation (MKI67, TOP2A, CCNE2), senescence (TERT, TERC), apoptosis (BIRC5/Survivin, TP73) and extracellular matrix remodeling (MMP13, MMP9, TIMP4, ITGB4). More interestingly, other genes were involved in the Ras signaling pathway (RASSF2, HMMR/RHAMM) and the Hedgehog-Gli signaling pathway (DHH, PTCH2). Several of the down-regulated genes were Schwann cell-specific (L1CAM, MPZ, S100B, SOX10, ERBB3) or mast cell-specific (CMA1, TPSB), pointing to a depletion and/or dedifferentiation of Schwann cells and mast cells during malignant transformation of plexiform neurofibromas. CONCLUSION: These data suggest that a limited number of signaling pathways, and particularly the Hedgehog-Gli signaling pathway, may be involved in malignant transformation of plexiform neurofibromas. Some of the relevant genes or their products warrant further investigation as potential therapeutic targets in NF1

Fos but not Cart (cocaine and amphetamine regulated transcript) is overexpressed by several drugs of abuse: a comparative study using real-time quantitative polymerase chain reaction in rat brain.

International audienceIt has been reported that cocaine and amphetamine-regulated transcript (Cart) peptides can increase locomotor activity and produce a conditioned place preference. To establish whether or not Cart can be consider as a valuable marker of addiction we performed a comparative study of the expression of Cart and Fos genes by several drugs of abuse. This was achieved using real-time quantitative polymerase chain reaction in four rat brain structures: prefrontal cortex, caudate putamen, nucleus accumbens and hippocampus. As expected, a significant induction of the immediate early gene Fos was observed after acute administration of morphine, cocaine, 3, 4-methylenedioxymethamphetamine and Delta(9)-Tetrahydrocannabinol. On the contrary none of these drugs was able to produce a significant change in Cart mRNA levels demonstrating that the expression of this gene is not modulated by drugs of abuse in these brain structures

Mid- and Far-Infrared Marker Bands of the Metal Coordination Sites of the Histidine Side Chains in the Protein Cu,Zn-Superoxide Dismutase

International audienceVibrational spectroscopy gives important information on the properties of ligand and metal–ligand bonds in metalloenzymes. Infrared spectroscopy is appealing for the study of metal active sites that are not amenable to Raman spectroscopy. We present a combined experimental and theoretical approach to analyze the mid- and far-IR spectra of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) as a probe of the histidine ligands. This metalloenzyme provides a unique model to identify specific IR signatures of metal–histidine coordination and to study their alterations as a function of the metal (copper/zinc), the copper valence state (+I/+II), the histidine coordination mode (Nτ and Nπ) and the histidine protonation state. DFT calculations combined with normal mode descriptions from potential energy distribution calculations were performed on two slightly different cluster models. Differences in the constraints at the side chain of one histidine Cu ligand sensibly modify the geometric parameters and vibrational properties. Electrochemically induced FTIR difference spectroscopy provided mid- and far-IR fingerprint spectra of the Cu protein in aqueous media that are sensitive to the redox state of the Cu centre at the active site. Comparisons of the DFT predictions with the experimental IR modes of the histidine ligands at the Cu,Zn-SOD active site showed that useful mid-IR markers of histidine Nτ and Nπ coordination were predicted with good accuracy. The DFT analysis further demonstrated a link between the ν(C4–C5) mode frequency of His46 and the specific properties of the His46–Cu bond in Cu,Zn-SOD. A combined theoretical and experimental approach on samples in H2O and 2H2O or 15N-labelled samples identified the contributions from the histidine side chain modes in the 669–629 cm–1 region

Guerra de la Independencia : narración histórica de los acontecimientos de aquella época, precedida del relato crítico de los sucesos de mas bulto ocurridos durante el reinado de Carlos \RIV\R, seguida del de la época de 1814 a 1820, de la constitucional de 1820 á 1823, y de la continuación del reinado de Fernando \RVII\R hasta la muerte de este monarca, y terminada con un cuadro ó exámen comparativo de los reinados de Carlos \RIV\R y Fernando \RVII\R

Copia digital : Diputación de Málaga. Biblioteca Canovas del Castillo, 2015El t. \RII\R impreso por: "Imp. del Siglo a cargo de Ivo Biosca

Vékonyréteg-kromatográfiás módszer benzoesav specifikus kimutatására

Zum Nachweis der Benzoesäure in Lebensmitteln wird eine auf der Anwendung eines Bromphenolblau enthaltenden spezifischen Entwicklers beruhenden dünnschichtchromatographischen Methode beschrieben. Diese Methode kann nützlich sein, falls ein Lebensmittel gleichzeitig Sorbinsäure und Benzoesäure enthält. Sorbinsäure und Benzoesäure von dem selben R^-Wert sind nämlich m it der entwickelten Methode nachweisbar, wenn man beiden vorgeschlagenen Entwickler nacheinander anwendet. Auch andere Entwickler sind anwendbar zum Nachweis der Anwesenheit von anderen möglichen fungistatischen Substanzen im untersuchten Muster. Falls der anwesende Entwickler bekannt ist, kann sogar die zur quantitativen Bestimmung geeignete Methode ausgewählt und angewendet werden. A novel method is presented for the detection of benzoic acid in foods. This thin-layer chromatographic method is based on the use of a specific developer containing bromophenolblue. The method may be useful when sorbic, acid and benzoic acid are simultaneously present in the same food. Sorbic acid and benzoic acid of the same Revalue can be detected by the developed method when the proposed two developers are used after each otherc. Also another developer may be suitable for the detection of other fungistatic substances in the sample. If the applied additive is known, an adequate method may be selected and applied even for its quantitative determination

CD1 Gene Polymorphisms and Phenotypic Variability in X-Linked Adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is characterized by marked phenotypic variation ranging from adrenomyeloneuropathy (AMN) to childhood cerebral ALD (CCALD). X-ALD is caused by mutations in the ABCD1 gene, but no genotype-phenotype correlation has been established so far and modifier gene variants are suspected to modulate phenotypes. Specific classes of lipids, enriched in very long-chain fatty acids that accumulate in plasma and tissues from X-ALD patients are suspected to be involved in the neuroinflammatory process of CCALD. CD1 proteins are lipid- antigen presenting molecules encoded by five CD1 genes in human (CD1A-E). Association studies with 23 tag SNPs covering the CD1 locus was performed in 52 patients with AMN and 87 patients with CCALD. The minor allele of rs973742 located 4-kb downstream from CD1D was significantly more frequent in AMN patients (χ2 = 7.6; P = 0.006). However, this association was no longer significant after Bonferroni correction for multiple testing. The other polymorphisms of the CD1 locus did not reveal significant association. Further analysis of other CD1D polymorphisms did not detect stronger association with X-ALD phenotypes. Although the association with rs973742 warrants further investigations, these results indicate that the genetic variants of CD1 genes do not contribute markedly to the phenotypic variance of X-ALD

IFI35, mir-99a and HCV Genotype to Predict Sustained Virological Response to Pegylated-Interferon Plus Ribavirin in Chronic Hepatitis C

International audienceAlthough, the treatment of chronic hepatitis C (CHC) greatly improved with the use of direct antiviral agents, pegylated-interferon (PEG-IFN) plus ribavirin remains an option for many patients, worldwide. The intra-hepatic level of expression of interferon stimulated genes (ISGs) and the rs12979860 CC genotype located within IFNL3 have been associated with sustained virological response (SVR), in patients with CHC. The aim of the study was to identify micro-RNAs associated with SVR and to build an accurate signature to predict SVR. Pre-treatment liver biopsies from 111 patients, treated with PEG-IFN plus ribavirin, were studied. Fifty-seven patients had SVR, 36 non-response (NR) and 18 relapse (RR). The expression of 851 human miRNAs and 30 selected mRNAs, including ISGs, was assessed by RT-qPCR. In the first group of patients (screen), 20 miRNAs out of the 851 studied were deregulated between NRs and SVRs. From the 4 miRNAs validated (mir-23a, mir-181a*, mir-217 and mir-99a), in the second group of patients (validation), 3 (mir-23a, mir-181a* and mir-99a) were down-regulated in NRs as compared to SVRs. The ISGs, studied, were accumulated in SVRs and IFNL3 rs12979860 CT/TT carriers compared respectively to NRs and CC carriers. Combining, clinical data together with the expression of selected genes and micro-RNAs, we identified a signature (IFI35, mir-99a and HCV genotype) to predict SVR (AUC:0.876) with a positive predictive value of 86.54% with high sensibility (80%) and specificity (80.4%). This signature may help to characterize patients with low chance to respond to PEG-IFN/ribavirin and to elucidate mechanisms of NR

La ingeniería civil, la enseñanza y la investigación, también son femeninas

La Universidad juega un papel esencial en su vínculo indisoluble con la sociedad. Se encarga de formar a las nuevas generaciones dotándolas de una cultura general integral que les permita un adecuado desempeño profesional La Universidad de Oriente en Santiago de Cuba, se destaca por su reconocido impacto en la docencia, las investigaciones y el posgrado. El liderazgo ejercido por las mujeres es evidente y se refleja en los resultados que se alcanzan en el alto centro docente. Se realiza un diagnóstico para evaluar la participación de la mujer en la enseñanza de la Ingeniería civil en el oriente de Cuba, así como en el desarrollo de investigaciones que responden a prioridades de los Organismos de la Administración Central del Estado y las necesidades del territorio. Se valora el rol que desempeñan las mujeres dentro del claustro del departamento Ingeniería Civil de la Facultad de Construcciones enfocado hacia su desempeño profesional, docente e investigativo Este colectivo de mujeres ha contribuido a la formación de más de 300 ingenieros civiles de las provincias orientales. Además, han participado en importantes investigaciones agrupadas en tres resultados fundamentales como: Valoración de tecnologías para viviendas construidas con materiales alternativos y sistemas constructivos para su adecuado desempeño en zonas sísmicas, Aspectos tecnológicos para la construcción de estructuras sismorresistentes de hormigón armado y Empleo de áridos y materiales alternativos en la obtención de mezclas de hormigones, morteros y enlucidos. Estos resultados están vinculados a proyectos de investigación y poseen impactos científicos, sociales, económicos y medioambientales que demuestran su contribución al desarrollo socioeconómico, territorial y local