Translation and fates of the gag protein of 1731, a Drosophila melanogaster retrotransposon

AbstractAn entire copy of 1731, a Drosophila melanogaster retrotransposon, was tagged by fusing in frame its putative gag gene with the reporter LacZ sequence. The high transfection efficiency of Drosophila virilis cells added to the absence of 1731 in their genome allowed, by combining histochemical staining and immunological detections, the demonstration of the translation of the 1731 gag gene. The gag protein is gathered in virus-like particles. Its occurrence in nuclei is consistent with a nuclear localization signal. The expression of the sense construction was inhibited by cotransfections with its antisense homologue

On the Mechanism of Action of H 2 O 2 in the Cellular Stress

International audienceWe propose a hypothesis according to which the reactive and reduced species of oxygen could be the intracellular inducers of the stress (or "heat-shock") response. This hypothesis is based on the following observations on Drosophila cells: a) the return to normoxia after 24 h anaerobiosis is sufficient to induce the synthesis of the "heat shock" proteins without elevation of temperature together with a rapid increase of O2 consumption; b) hydrogen peroxide introduced in the culture medium induces the early transcriptional activation of the "heat shock" genes (maximal after 5 minutes); c) hydrogen peroxide added to cellular extracts in vitro (thus acting as an intracellular metabolite) activates instantaneously the binding capacity of a "heat shock" factor to a DNA "heat shock" regulatory element. Thus, hydrogen peroxide, and possibly other reactive reduced species of oxygen, could trigger the onset of the stress (or "heat shock") response

Pigments et production d'H

Les auteurs mettent en évidence le rôle de la catalase dans les propriétés radioprotectrices de l'hémocyanine et dans la cancérogenèse de la peau humaine. Ils montrent notamment comment l'application de pommade à la catalase a stoppé révolution cancéreuse d'enfants atteints de Xeroderma Pigmentosum (XP). Bien que les résultats cliniques et biologiques ne permettent pas encore une conclusion catégorique, ils soulignent le fait qu'une insuffisance de l'activité catalatique pourrait constituer un facteur important dans le développement de XP et qu'à l'inverse une activité catalatique puissante pourrait représenter un facteur non négligeable dans la radiorésistance élevée du scorpion

Crucial role of the amino-terminal tyrosine residue 42 and the carboxy-terminal PEST domain of IkappaBalpha in NF-kappaB activation by an oxidative stress

peer reviewe

Crucial Role of the Amino-Terminal Tyrosine Residue 42 and the Carboxyl-Terminal PEST Domain of IκBα in NF-κB Activation by an Oxidative Stress

peer reviewe