Differential binding regulation of microtubule-associated proteins MAP1A, MAP1B, and MAP2 by tubulin polyglutamylation.

The major neuronal post-translational modification of tubulin, polyglutamylation, can act as a molecular potentiometer to modulate microtubule-associated proteins (MAPs) binding as a function of the polyglutamyl chain length. The relative affinity of Tau, MAP2, and kinesin has been shown to be optimal for tubulin modified by approximately 3 glutamyl units. Using blot overlay assays, we have tested the ability of polyglutamylation to modulate the interaction of two other structural MAPs, MAP1A and MAP1B, with tubulin. MAP1A and MAP2 display distinct behavior in terms of tubulin binding; they do not compete with each other, even when the polyglutamyl chains of tubulin are removed, indicating that they have distinct binding sites on tubulin. Binding of MAP1A and MAP1B to tubulin is also controlled by polyglutamylation and, although the modulation of MAP1B binding resembles that of MAP2, we found that polyglutamylation can exert a different mode of regulation toward MAP1A. Interestingly, although the affinity of the other MAPs tested so far decreases sharply for tubulins carrying long polyglutamyl chains, the affinity of MAP1A for these tubulins is maintained at a significant level. This differential regulation exerted by polyglutamylation toward different MAPs might facilitate their selective recruitment into distinct microtubule populations, hence modulating their functional properties

Bi-Modal Person Recognition on a Mobile Phone: using mobile phone data

This paper presents a novel fully automatic bi-modal, face and speaker, recognition system which runs in real-time on a mobile phone. The implemented system runs in real-time on a Nokia N900 and demonstrates the feasibility of performing both automatic face and speaker recognition on a mobile phone. We evaluate this recognition system on a novel publicly-available mobile phone database and provide a well defined evaluation protocol. This database was captured almost exclusively using mobile phones and aims to improve research into deploying biometric techniques to mobile devices. We show, on this mobile phone database, that face and speaker recognition can be performed in a mobile environment and using score fusion can improve the performance by more than 25% in terms of error rates

L-Ilf3 and L-NF90 Traffic to the Nucleolus Granular Component: Alternatively-Spliced Exon 3 Encodes a Nucleolar Localization Motif

Ilf3 and NF90, two proteins containing double-stranded RNA-binding domains, are generated by alternative splicing and involved in several functions. Their heterogeneity results from posttranscriptional and posttranslational modifications. Alternative splicing of exon 3, coding for a 13 aa N-terminal motif, generates for each protein a long and short isoforms. Subcellular fractionation and localization of recombinant proteins showed that this motif acts as a nucleolar localization signal. Deletion and substitution mutants identified four arginines, essential for nucleolar targeting, and three histidines to stabilize the proteins within the nucleolus. The short isoforms are never found in the nucleoli, whereas the long isoforms are present in the nucleoplasm and the nucleoli. For Ilf3, only the posttranslationally-unmodified long isoform is nucleolar, suggesting that this nucleolar targeting is abrogated by posttranslational modifications. Confocal microscopy and FRAP experiments have shown that the long Ilf3 isoform localizes to the granular component of the nucleolus, and that L-Ilf3 and L-NF90 exchange rapidly between nucleoli. The presence of this 13 aminoacid motif, combined with posttranslational modifications, is responsible for the differences in Ilf3 and NF90 isoforms subcellular localizations. The protein polymorphism of Ilf3/NF90 and the various subcellular localizations of their isoforms may partially explain the various functions previously reported for these proteins

Aspects cellulaires et biochimiques de la neurogenese. Etude des oncogenes nucleaires

Available from INIST (FR), Document Supply Service, under shelf-number : T 78453 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Ilf3 and NF90 functions in RNA biology

International audienceDouble-stranded RNA-binding proteins (DRBPs) are known to regulate many processes of RNA metabolism due, among others, to the presence of double-stranded RNA (dsRNA)-binding motifs (dsRBMs). Among these DRBPs, Interleukin enhancer-binding factor 3 (Ilf3) and Nuclear Factor 90 (NF90) are two ubiquitous proteins generated by mutually exclusive and alternative splicings of the Ilf3 gene. They share common N-terminal and central sequences but display specific C-terminal regions. They present a large heterogeneity generated by several post-transcriptional and post-translational modifications involved in their subcellular localization and biological functions. While Ilf3 and NF90 were first identified as activators of gene expression, they are also implicated in cellular processes unrelated to RNA metabolism such as regulation of the cell cycle or of enzymatic activites. The implication of Ilf3 and NF90 in RNA biology will be discussed with a focus on eukaryote transcription and translation regulation, on viral replication and translation as well as on noncoding RNA field. WIREs RNA 2015, 6:243-256. doi: 10.1002/wrna.1270 For further resources related to this article, please visit the . Conflict of interest: The authors have declared no conflicts of interest for this article

SV 40 induced cellular immortalization: phenotypic changes associated with the loss of proliferative capacity in a conditionally immortalized cell line

International audienceImmortalization of rodent embryo fibroblasts by SV 40 is dominantly maintained by the large T antigen. The aim of this work is to characterize some of the events associ ated with the Joss of proliferative capacity in a rat cell line, called REtsAF, which is conditionally immortalized by the tsA58 allele of SV 40 large T antigen. DNA repli cation is arrested Jess than 24 h after the shift to the restrictive temperature (39°C). This arrest occurs without specificity relative to the cell cycle stage, which suggests that a fonction essential throughout the cell cycle is affected. A two-dimensional SOS polyacrylamide gel electrophoresis analysis of proteins shows that, although the global rate of protein synthesis is only slightly affected at 39°C, the rate of accumulation of specific pro teins is either increased or decreased. Finally we present biochemical and electron microscopy data showing that alterations of the mitochondria occur upon shift to 39°C

SV 40 induced cellular immortalization: phenotypic changes associated with the loss of proliferative capacity in a conditionally immortalized cell line

International audienceImmortalization of rodent embryo fibroblasts by SV 40 is dominantly maintained by the large T antigen. The aim of this work is to characterize some of the events associ ated with the Joss of proliferative capacity in a rat cell line, called REtsAF, which is conditionally immortalized by the tsA58 allele of SV 40 large T antigen. DNA repli cation is arrested Jess than 24 h after the shift to the restrictive temperature (39°C). This arrest occurs without specificity relative to the cell cycle stage, which suggests that a fonction essential throughout the cell cycle is affected. A two-dimensional SOS polyacrylamide gel electrophoresis analysis of proteins shows that, although the global rate of protein synthesis is only slightly affected at 39°C, the rate of accumulation of specific pro teins is either increased or decreased. Finally we present biochemical and electron microscopy data showing that alterations of the mitochondria occur upon shift to 39°C

SV 40 induced cellular immortalization: phenotypic changes associated with the loss of proliferative capacity in a conditionally immortalized cell line

International audienceImmortalization of rodent embryo fibroblasts by SV 40 is dominantly maintained by the large T antigen. The aim of this work is to characterize some of the events associ ated with the Joss of proliferative capacity in a rat cell line, called REtsAF, which is conditionally immortalized by the tsA58 allele of SV 40 large T antigen. DNA repli cation is arrested Jess than 24 h after the shift to the restrictive temperature (39°C). This arrest occurs without specificity relative to the cell cycle stage, which suggests that a fonction essential throughout the cell cycle is affected. A two-dimensional SOS polyacrylamide gel electrophoresis analysis of proteins shows that, although the global rate of protein synthesis is only slightly affected at 39°C, the rate of accumulation of specific pro teins is either increased or decreased. Finally we present biochemical and electron microscopy data showing that alterations of the mitochondria occur upon shift to 39°C

Functionalisation of free amino groups of lysine dendrigraft (DGL) polymers

International audienceLysine dendrigraft polymers (DGL) are promising candidates as carriers for targeted drug/gene delivery and bio-imaging, as such deserving extensive chemical functionalisation studies. We describe here examples of complete grafting of DGL amino groups by various substituents: hydrophobic amino acids (Ala, Val, Leu), dicarboxylic acids (succinic, Asp), guanidyl and saccharides (Gal), by means of straightforward coupling reactions, thus opening to versatile tuning of DGL properties (hydrophobicity, nucleophilicity, electric charge . . .). DGL functionalisation by lactose (when carried out so as to avoid borate ester formation between sugars) however yields partially grafted DGL; besides, partial grafting can be achieved by tuning the reagent/DGL stoichiometric ratio

Effect of Experimental Infection with Haemonchus contortus on Parasitological and Local Cellular Responses in Resistant and Susceptible Young Creole Goats

This study was carried out to evaluate the relationships of cellular changes in the abomasal mucosa and parasitological parameters, by comparing resistant and susceptible young Creole goats (kids) after experimental infection with Haemonchus contortus. The kids were infected over 2 periods (challenges 1 and 2) of 7 and 6 weeks, respectively. Fecal egg count (FEC), blood eosinophilia, packed cell volume (PCV), and body weight were weekly monitored. At the end of both challenges a subgroup of kids was slaughtered for nematode burden measurements and analysis of inflammatory cell infiltration in the abomasal mucosa. The average daily gain was higher in resistant kids after both challenges. Blood eosinophilia and FEC were higher in susceptible kids after both challenges. The number of immature worms and the means of female length were lower after challenge 2 whatever the genetic status. No differences were observed in the eosinophil and mononuclear cell infiltration between challenges 1 and 2 and resistant and susceptible kids. Globule leukocyte infiltration was found higher after the challenge 1 in resistant kids. This effect of the genetic status on globule leukocytes counts but not on the other inflammatory cell highlights the need for further study on the functional activity of these cell populations