RT Journal Article
SR Electronic
T1 Homeostasis of protein and mRNA concentrations in growing cells
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 255950
DO 10.1101/255950
A1 Jie Lin
A1 Ariel Amir
YR 2018
UL http://biorxiv.org/content/early/2018/06/11/255950.abstract
AB Many experiments show that the numbers of mRNA and protein are proportional to the cell volume in growing cells. However, models of stochastic gene expression often assume constant transcription rate per gene and constant translation rate per mRNA, which are incompatible with these experiments. Here, we construct a minimal gene expression model to fill this gap. Assuming ribosomes and RNA polymerases are limiting in gene expression, we find that (1) because the ribosomes translate all proteins, the concentrations of proteins and mRNAs are regulated in an exponentially growing cell volume; (2) the competition between genes for the RNA polymerases makes the transcription rate independent of the genome number. Furthermore, by extending the model to situations in which DNA (mRNA) can be saturated by RNA polymerases (ribosomes) and becomes limiting, we predict a transition from exponential to linear growth of cell volume as the protein-to-DNA ratio increases.