Synthese rationnelle de clusters heterometalliques

CNRS T 57310 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

A Procedure for Northern Blot Analysis of Native RNA

We describe a modification of the Northern technique that allows the detection of RNA either native and/or containing hidden breaks. We found that the highest sensitivity of the hybridization signals was obtained after denaturation of the RNA in the gel prior to its transfer onto a nylon membrane (GeneScreen) followed by uv irradiation. The sensitivity of the method using native RNA was found to be equivalent to that obtained with denatured RNA

It is Rous Sarcoma Virus Protein P12 and not P19 that Binds Tightly to Rous Sarcoma virus RNA

The interactions between Rous Sarcoma virus (RSV) RNA and the viral proteins in the virus have been analysed by Sen & Todaro (1977) using ultraviolet light irradiation; they showed that the major protein ultraviolet light cross-linked to the viral RNA was P19 as identified by polyacrylamide gel electrophoresis. We report here that it is not viral protein P19 but P12 that binds tightly to RSV RNA upon ultraviolet light irradiation of the virus. Therefore, the binding sites of the viral protein along RSV RNA that we have characterized previously should be correctly attributed now to P12 and not P19

Système radar FMCW pour l'identification de transpondeurs

International audienceIn this paper, we deal with a frequency modulated continuous wave (FMCW) radar used for localizing and tracking targets by frequency evaluation of the received radar beat signal. We consider the transponder as target and we achieve an identification application through frequency identification thanks to the shift frequency induced by the active target. The localization performance of FMCW radars based on radio-identification in the range (SHF) are presented and studied. Simulations and measurements complete the paper.Dans cet article, nous traitons d'un système radar à onde continue à modulation de fréquence (FMCW) utilisé pour localiser et suivre des cibles par l'évaluation de la fréquence du signal de battement radar reçu. Nous considérons un transpondeur linéaire comme cible et nous réalisons une identification de cible grâce à la fréquence de décalage induite par cette cible active. Les performances de localisation des radars FMCW basés sur la radio-identification dans la gamme (SHF) sont présentées et étudiées. Des simulations et des mesures viennent compléter le papier

Non-linear Effect Mitigation for FMCW Radar System

International audienceIn this paper, we deal with a frequency modulated continuous wave (FMCW) radar used for localizing and tracking targets by frequency evaluation of the received radar beat signal. The radar system achieved with a primary radar (reader) and a secondary radar (transponder) is addressed as super high frequency (SHF) radio frequency identification (RFID). Consequently, considering the transponder as an active target, we achieve an identification application thanks to the shift frequency induced by the transponder. Moreover, the impact of the non-linearity behavior of this transponder on the localization performance, is investigated and a solution is proposed for cancelling non-linear effects

The interactions of viral proteins with Rous Sarcoma virus RNA and possible control of reversible transcription, translation and virion assembly

The interactions between Rous Sarcoma virus RNA and the viral proteins have been analysed in the virus and in vitro. We show that it is protein Pl2 and not Pl9 that binds tightly to RSV RNA both in the virus and in vitro. Specific RNA sequences are recognized by protein Pl2 in the virus and such sequences are close to or involve the splice sites, and the dimer linkage site likely to be required for viral packaging. In vitro Pl2 does not impair proviral DNA synthesis whereas it can completely inhibit RNA translation. Such data suggest that Pl2 may control negatively viral RNA splicing and translation and positively the packaging process

Mutations in Rous Sarcoma Virus Nucleocapsid Protein p12 (NC): Deletions of Cys-His Boxes

Rous sarcoma virus nucleocapsid protein p12 (NC) contains two conserved amino acid motifs, the Cys-His boxes, which constitute potential metal-binding domains. To try to understand the function of NC and of each of its Cys-His boxes during the viral life cycle, particularly in viral RNA packaging, we have used synthetic oligonucleotides to delete precisely either the proximal or the distal box, or both Cys-His boxes. The mutant DNAs were transfected into chicken embryo fibroblasts, and the virions produced in a transient assay were characterized biochemically for production of viral proteins and particles, RNA packaging, and infectivity. The results indicated the following. (i) The deletion of either the proximal or the distal box decreases the amount of viral RNA packaged in the particles and results in incomplete 70S dimer formation. (ii) The deletion of both boxes inhibits viral RNA packaging. (iii) The deletion of the proximal, but not the distal, box suppresses any detectable infectivity, while the deletion of the distal, but not the proximal, box lowers infectivity 100 to 200 times