RT Journal Article
SR Electronic
T1 Codon-dependent noise dictates cell-to-cell variability in nutrient poor environments
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 492207
DO 10.1101/492207
A1 Enrique Balleza
A1 Lisa F. Marshall
A1 J. Mark Kim
A1 Philippe Cluzel
YR 2018
UL http://biorxiv.org/content/early/2018/12/10/492207.abstract
AB Under nutrient-rich conditions, stochasticity of transcription drives protein expression noise. However, by shifting the environment to amino acid-limited conditions, we identified in E. coli a source of noise whose strength is dictated by translational processes. Specifically, we discovered that cell-to-cell variations in fluorescent protein expression depend on codon choice, with codons yielding lower mean expression after amino acid downshift also resulting in greater noise. We propose that ultra-sensitivity in the tRNA charging/discharging cycle shapes the strength of the observed noise by amplifying fluctuations in global intracellular parameters, such as the concentrations of amino acid, synthetase, and tRNA. We hypothesize that this codon-dependent noise may allow bacteria to selectively optimize cell-to-cell variability in poor environments without relying on low molecular numbers.