Influence of Multiplicative Stochastic Variation on Translational Elongation Rates
Recent experiments have shown that stochastic effects exerted at the level of translation contribute a substantial portion of the variation in abundance of proteins expressed at moderate to high levels. This study analyzes translational noise arising from fluctuations in residue-specific elongation rates. The resulting variation has multiplicative components that lead individual protein abundances in a population to exhibit approximately log-normal behavior. The high variability inherent in the process leads to parameter variation that has the features of a type of noise in biological systems that has been characterized as extrinsic. Elongation rate variation offers an accounting for a major component of extrinsic noise, and the analysis provided here highlights a probability distribution that is a natural extension of the Poisson and has broad applicability to many types of multiplicative noise processes.