Plasmid-borne prokaryotic gene expression: sources of variability and quantitative system characterization.

摘要: One aim of synthetic biology is to exert systematic control over cellular behavior, either for medical purposes or "program" microorganisms. An engineering approach the design biological controllers demands a quantitative understanding dynamics both system be controlled and themselves. Here we focus on widely used method exerting in bacterial cells: plasmid vectors bearing gene-promoter pairs. We study two variants simplest such element, an unregulated promoter constitutively expressing its gene, against varying genomic background four Escherichia coli cell strains. Absolute protein numbers rates expression vary with strain type, as does variability across population. Total most strongly coupled division process, after size scaled away, copy number regulation emerges significant effect. present simple models that capture main features behavior. Our results confirm complex interactions between plasmids their hosts can have effects variability, even deliberately simplified systems.