Genetic specification of left-right asymmetry in the diaphragm muscles and their motor innervation.

The diaphragm muscle is essential for breathing in mammals. Its asymmetric elevation during contraction correlates with morphological features suggestive of inherent left-right (L/R) asymmetry. Whether this asymmetry is due to L versus R differences in the muscle or in the phrenic nerve activity is unknown. Here, we have combined the analysis of genetically modified mouse models with transcriptomic analysis to show that both the diaphragm muscle and phrenic nerves have asymmetries, which can be established independently of each other during early embryogenesis in pathway instructed by Nodal, a morphogen that also conveys asymmetry in other organs. We further found that phrenic motoneurons receive an early L/R genetic imprint, with L versus R differences both in Slit/Robo signaling and MMP2 activity and in the contribution of both pathways to establish phrenic nerve asymmetry. Our study therefore demonstrates L-R imprinting of spinal motoneurons and describes how L/R modulation of axon guidance signaling helps to match neural circuit formation to organ asymmetry

gdnf activates midline repulsion by Semaphorin3B via NCAM during commissural axon guidance

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S-adenosyl methionine decarboxylase activity is required for the outcome of herpes simplex virus type 1 infection and represents a new potential therapeutic target.

All the available antiherpetic drugs are directed against viral proteins. Their extensive clinical use has led to the emergence of resistant viral strains. There is a need for the treatment of herpes infections due to resistant strains, especially for immunocompromised patients. To design new kinds of drugs, we have developed a strategy to identify cellular targets. Herpes simplex virus type 1 (HSV-1) infection is concomitant to a repression of most host protein synthesis. However, some cellular proteins continue to be efficiently synthesized. We speculated that some of them could determine the outcome of infection. Since two polyamines, spermidine and spermine, are components of the HSV-1 virions, we investigated whether enzymes involved in their synthesis could be required for viral infection. We show that inhibition of S-adenosyl methionine decarboxylase, a key enzyme of the polyamine metabolic pathway, prevents HSV-1 infection. Inhibition of polyamine synthesis prevents infection of culture cells with HSV-1 laboratory strains as well as clinical isolates that are resistant to the conventional antiviral drugs acyclovir and foscarnet. Our data provide the opportunity to develop molecules with a novel mechanism of action for the treatment of herpes infection

PlexinA1 is a new Slit receptor and mediates axon guidance function of Slit C-terminal fragments

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