Modulating the level of protein biosynthetic machinery in response to growth conditions is of utmost importance to every living cell. In E. coli, two different regulatory systems couple the rate of ribosomal RNA (rRNA) synthesis to growth rate. However, the actual mechanism(s) linking the central metabolism of the cell to the rate of rRNA synthesis remain completely unknown. The observation that increased amounts of fructose 1,6 biphosphate (FbP) preferentially inhibits in connecting central metabolism regulation of rRNA synthesis. The development of a crude transcription-translation system in which FbP specially inhibits rRNA synthesis provides an experimental system for dissecting this effect. Experiments to determine whether RNA polymerase alone or additional factors in the crude extract are needed for inhibition will determine the target of FbP action. Genetic analysis of this interaction will establish the growth conditions under which the regulatory circuit involving FbP is operative. %%% This project offers a chance to understand a molecular circuit that couples rRNA synthesis to carbon metabolism, a problem of central importance to every living organism that has not been elucidated in any experimental system.
