XXXX and the French School of Molecular Biology.

@entity1132 @entity46272 @entity526
Andr   Lwoff, Jacques Monod, and Fran  ois Jacob, the leaders of the French school of molecular biology, greatly contributed between 1937 and 1965 to its development and triumph. The main discovery of Lwoff was the elucidation of the mechanism of bacteriophage induction, the phenomenon of lysogeny, that led to the model of genetic regulation uncovered later by Jacob and Monod. Working on bacterial growth, Monod discovered in 1941 the phenomenon of diauxy and uncovered the nature of enzyme induction. By combining genetic and biochemical approaches, Monod brought to light the structure and functions of the @entity526 @entity1132 system, comprising the genes necessary for @entity1132 metabolism, i.e., b-galactosidase and @entity1132 permease, a pump responsible for accumulation of @entity46272 into the cells. An additional genetic factor (the i gene) determines the inducibility and constitutivity of enzyme synthesis. Around the same time, Fran  ois Jacob and Elie Wollman dissected the main events of bacterial conjugation that enabled them to construct a map of the @entity526 chromosome and to demonstrate its circularity. The genetic analysis of the @entity1132 system led Monod and Jacob to elucidate the mechanism of the regulation of gene expression and to propose the operon model: a unit of coordinate transcription. One of the new concepts that emerged from the operon model was messenger RNA. In 1963, Monod developed one of the most elegant concepts of molecular biology, the theory of allostery. In 1965, Lwoff, Monod and Jacob were awarded the Nobel Prize in Physiology or Medicine.
