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par - 15 septembre 2011
Certain viruses are known to be capable of producing numerous proteins despite the small size of their genome. For example, human retroviruses express structural proteins, enzymes, regulatory and accessory proteins in the context of a RNA genome, which does not exceed 10 kilobases in size. Genome of these viruses exists in two different forms : either as a single stranded RNA being translated or encapsidated, or as a double stranded DNA integrated in the genome of the infected host cell. This latter form, also termed proviral DNA, is crucial for the production of all viral mRNAs necessary for the synthesis of the various viral proteins, which in turn involves the promoter region localised in the 5’ LTR (Long Terminal Repeat). However, proviral DNA also possesses a second LTR at its 3’ end, capable of regulating a type of transcription known as antisense, as it is surprisingly oriented in the inverse direction from the transcription controlled by the 5’ LTR. Proviral DNA therefore has two encoding strands, which thereby lead to a greater potential for synthesis of different proteins in comparison to single stranded RNA. In collaboration with the laboratory of Pr. Benoit Barbeau (University of Quebec in Montreal) we detected in HTLV-1, HTLV-2 and HIV-1-infected cell lines antisense transcripts, which are able to encode retroviral antisense proteins. One of our purposes is to characterize the function of the antisense proteins encoded by HTLV-1 (HBZ for HTLV-1 bZIP factor) and HIV-1 (ASP for AntiSens Protein). Moreover, we are studying the mechanisms regulating HIV-1 Tat secretion as well as the effect of Tat-PIP2 interaction on important machineries whose key players are recruited by PIP2 : exocytosis, endocytosis and phagocytosis. Indeed, Tat has a better affinity for PIP2 compared to cellular proteins. Hence, Tat could interfere with some of these essential cell activities. This is especially the case for cells of the immune systems and neurons. This project is developed in collaboration with Nicolas Vitale et Petra Tryoen (INCI, CNRS, Strasbourg).
Group manager : Jean-Michel Mesnard
Contact : M MESNARD Jean-Michel
Phone : +33 [0]4 34 35 94 40 / 41
Members of the group : (from left to right)
CHOPARD Christophe – PhD student
MESNARD Jean-Michel – Group leader – DR2 CNRS
LAVERDURE Sylvain – PhD student
SARKIS Sarkis – PhD student
ARPIN-ANDRE Charlotte – AI CNRS
PELOPONESE Jean-Marie – CR1 CNRS
GROSS Antoine – CR1 CNRS
BEAUMELLE Bruno – DR2 CNRS
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