hnRNP A1 and hnRNP F Modulate the Alternative Splicing of Exon 11 of the Insulin Receptor Gene

Exon 11 of the insulin receptor gene (INSR) is alternatively spliced in a developmentally and tissue-specific manner. Linker scanning mutations in a 5′ GA-rich enhancer in intron 10 identified AGGGA sequences that are important for enhancer function. Using RNA-affinity purification and mass spectrometry, we identified hnRNP F and hnRNP A1 binding to these AGGGA sites and also to similar motifs at the 3′ end of the intron. The hnRNPs have opposite functional effects with hnRNP F promoting and hnRNP A1 inhibiting exon 11 inclusion, and deletion of the GA-rich elements eliminates both effects. We also observed specific binding of hnRNP A1 to the 5′ splice site of intron 11. The SR protein SRSF1 (SF2/ASF) co-purified on the GA-rich enhancer and, interestingly, also competes with hnRNP A1 for binding to the splice site. A point mutation -3U→C decreases hnRNP A1 binding, increases SRSF1 binding and renders the exon constitutive. Lastly, our data point to a functional interaction between hnRNP F and SRSF1 as a mutant that eliminates SRSF1 binding to exon 11, or a SRSF1 knockdown, which prevents the stimulatory effect of hnRNP F over expression

Achieving a cure for HIV infection: do we have reasons to be optimistic?

The introduction of highly active antiretroviral therapy (HAART) in 1996 has transformed a lethal disease to a chronic pathology with a dramatic decrease in mortality and morbidity of AIDS-related symptoms in infected patients. However, HAART has not allowed the cure of HIV infection, the main obstacle to HIV eradication being the existence of quiescent reservoirs. Several other problems have been encountered with HAART (such as side effects, adherence to medication, emergence of resistance and cost of treatment), and these motivate the search for new ways to treat these patients. Recent advances hold promise for the ultimate cure of HIV infection, which is the topic of this review. Besides these new strategies aiming to eliminate the virus, efforts must be made to improve current HAART. We believe that the cure of HIV infection will not be attained in the short term and that a strategy based on purging the reservoirs has to be associated with an aggressive HAART strategy

In vitro biocompatibility of a dentine substitute cement on human MG63 osteoblasts cells: Biodentine™ versus MTA ®

The authors also wish to express their appreciation to Beatrice Burdin, PhD, at the Microstructures Technology Center of University Claude Bernard Lyon1 for assistance with the SEM study. The AFM study was supported by the Characterization of Interactions Platform of the Nanobio Program, Grenoble University. We gratefully acknowledge the assistance on the English checking from Dr Huw Jones BSc PhD MRSC, Senior Lecturer in Chemistry for Environmental Science and Public Health, Middlesex University (UK).International audienceAimTo compare the in vitro biocompatibility of Biodentine and White ProRoot((R)) mineral trioxide aggregate (MTA((R))) with MG63 osteoblast-like cells and to characterize the cement surface. MethodologyA direct contact model for MG63 osteoblast-like cells with cements was used for 1, 3 and 5days. Four end-points were investigated: (i) cement surface characterization by atomic force microscopy (AFM), (ii) cell viability by MTT assay, (iii) protein amount quantification by Bradford assay and (iv) cell morphology by SEM. Statistical analyses were performed by analysis of variance (anova) with a repetition test method. ResultsThe roughness of the cements was comparable as revealed by AFM analysis. The MTT test for Biodentine was similar to that of MTA((R)). Biodentine and MTA((R)) induced a similar but slight decrease in metabolic activity. The amount of total protein was significantly enhanced at day three (P<0.05) but slightly decreased at day five for both tested samples. Biodentine was tolerated as well as MTA((R)) in all cytotoxicity assays. SEM observations showed improvement of cell attachment and proliferation on both material surfaces following the three incubation periods. ConclusionThe biocompatibility of Biodentine to bone cells was comparable to MTA((R))