Abstracts
Résumé
Que peut nous apprendre un ver sur le fonctionnement du cerveau humain? Les données acquises sur le système nerveux du nématode Caenorhabditis elegans démontrent l’existence d’une fascinante conservation de la biologie moléculaire et cellulaire du neurone au travers de plus de 550 millions d’années d’évolution séparant les nématodes des mammifères. C. elegans possède un système nerveux simple formé de 302 neurones et d’environ 7000 synapses. Des outils génétiques puissants permettent d’isoler de nouveaux gènes et d’attribuer à des gènes connus de nouvelles fonctions dans la mise en place et le fonctionnement du réseau neuronal du nématode. Nous montrerons par quelques exemples comment les découvertes faites chez C. elegans ont pu être rapidement transposées à la biologie du système nerveux des mammifères.
Summary
The human brain contains 100 billion neurons and probably one thousand times more synapses. Such a system can be analyzed at different complexity levels, from cognitive functions to molecular structure of ion channels. However, it remains extremely difficult to establish links between these different levels. An alternative strategy relies on the use of much simpler animals that can be easily manipulated. In 1974, S. Brenner introduced the nematode Caenorhabditis elegans as a model system. This worm has a simple nervous system that only contains 302 neurons and about 7,000 synapses. Forward genetic screens are powerful tools to identify genes required for specific neuron functions and behaviors. Moreover, studies of mutant phenotypes can identify the function of a protein in the nervous system. The data that have been obtained in C. elegans demonstrate a fascinating conservation of the molecular and cellular biology of the neuron between worms and mammals through more than 550 million years of evolution.
Appendices
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