title: Stochastic expression dynamics of a transcription factor revealed by single-molecule noise analysis.
abstract: Gene expression is inherently stochastic; precise gene regulation by transcription factors is important for cell-fate determination. Many transcription factors regulate their own expression, suggesting that autoregulation counters intrinsic stochasticity in gene expression. Using a new strategy, cotranslational activation by cleavage (CoTrAC), we probed the stochastic expression dynamics of cI, which encodes the bacteriophage λ repressor CI, a fate-determining transcription factor. CI concentration fluctuations influence both lysogenic stability and induction of bacteriophage λ. We found that the intrinsic stochasticity in cI expression was largely determined by CI expression level irrespective of autoregulation. Furthermore, extrinsic, cell-to-cell variation was primarily responsible for CI concentration fluctuations, and negative autoregulation minimized CI concentration heterogeneity by counteracting extrinsic noise and introducing memory. This quantitative study of transcription factor expression dynamics sheds light on the mechanisms cells use to control noise in gene regulatory networks.
authors: Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors: Zach
authors: Z
authors: Hensel
authors: Haidong
authors: H
authors: Feng
authors: Bo
authors: B
authors: Han
authors: Christine
authors: C
authors: Hatem
authors: Jin
authors: J
authors: Wang
authors: Jie
authors: J
authors: Xiao
mesh_terms: D010582:Bacteriophage lambda / Q000235:genetics / Q000378:metabolism; D048168:Escherichia coli K12 / Q000821:virology; D015870:Gene Expression; D005814:Genes, Viral; D006706:Homeostasis; D008954:Models, Biological; D014176:Protein Biosynthesis; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism*; D013269:Stochastic Processes; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D054334:Viral Regulatory and Accessory Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins