Biophysics Seminar Series - Philippe Cluzel, Harvard - The code within the code...
How bacteria use the degeneracy of the genetic code to control protein synthesis in fluctuating environments.
Most amino acids are represented in the genetic code by more than one codon. Codons coding for the same amino acid are referred to as synonymous. Over-expression of proteins can be optimized by adjusting the choice of synonymous codons. Introductions of synonymous mutations into endogenous genes, however, have been shown to have very little effect on protein levels. From these conflicting findings, it is unclear whether the degeneracy of the genetic code plays a role in protein expression at all. The studies of endogenous genes were done in the context of a nutrient-rich environment. Under these conditions, the bacteria E. coli expresses only about 1000 of its 4000 genes. By contrast, the majority of genes are activated when E. coli is in a stressful or nutrient-poor environment. This raises the question of whether E. coli could use synonymous codons differentially to optimize growth under nutrient-poor conditions. I will present experimental results, obtained from E. coli, aimed at identifying the role of synonymous codons in gene expression, at the protein level, when the environment switches from rich to poor nutrient conditions.
Location: Joseph Henry Room
Date/Time: 04/16/12 at 12:00 pm - 04/16/12 at 1:00 pm
Lunch @ 11:45, talk begins at 12 noon.
Category: Biophysics Seminar
Department: Physics