skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Nonlatching positive feedback enables robust bimodality by decoupling expression noise from the mean

Journal Article · · PLoS Biology (Online)
 [1];  [2];  [3];  [2]; ORCiD logo [4]; ORCiD logo [5]
  1. Rockefeller Univ., New York, NY (United States). Lab. of Virology and Infectious Disease; Gladstone Institutes (Virology and Immunology), San Francisco, CA (United States); Univ. of California, San Francisco, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Univ. of Tennessee, Knoxville, TN (United States). Bredesen Center for Interdisciplinary Research and Graduate Education
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Gladstone Institutes (Virology and Immunology), San Francisco, CA (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Univ. of Tennessee, Knoxville, TN (United States). Bredesen Center for Interdisciplinary Research and Graduate Education
  5. Gladstone Institutes (Virology and Immunology), San Francisco, CA (United States); Univ. of California, San Francisco, CA (United States). Dept. of Biochemistry and Biophysics; Univ. of California, San Francisco, CA (United States). QB3: California Inst. of Quantitative Biosciences; Univ. of California, San Francisco, CA (United States). Dept. of Pharmaceutical Chemistry

Fundamental to biological decision-making is the ability to generate bimodal expression patterns where two alternate expression states simultaneously exist. Here in this study, we use a combination of single-cell analysis and mathematical modeling to examine the sources of bimodality in the transcriptional program controlling HIV’s fate decision between active replication and viral latency. We find that the HIV Tat protein manipulates the intrinsic toggling of HIV’s promoter, the LTR, to generate bimodal ON-OFF expression, and that transcriptional positive feedback from Tat shifts and expands the regime of LTR bimodality. This result holds for both minimal synthetic viral circuits and full-length virus. Strikingly, computational analysis indicates that the Tat circuit’s non-cooperative ‘non-latching’ feedback architecture is optimized to slow the promoter’s toggling and generate bimodality by stochastic extinction of Tat. In contrast to the standard Poisson model, theory and experiment show that non-latching positive feedback substantially dampens the inverse noise-mean relationship to maintain stochastic bimodality despite increasing mean-expression levels. Given the rapid evolution of HIV, the presence of a circuit optimized to robustly generate bimodal expression appears consistent with the hypothesis that HIV’s decision between active replication and latency provides a viral fitness advantage. More broadly, the results suggest that positive-feedback circuits may have evolved not only for signal amplification but also for robustly generating bimodality by decoupling expression fluctuations (noise) from mean expression levels.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Office of Science (SC); National Institutes of Heath (NIH); National Science Foundation (NSF); Netherlands Organization of Scientific Research (NWO); W.M. Keck Foundation; Alfred P. Sloan Research Foundation; National Institutes of Health (NIH)
Grant/Contract Number:
AC05-00OR22725; AC52-06NA25396; OD006677; R01OD011095; ACI-1053575; 019.153LW.028
OSTI ID:
1407734
Alternate ID(s):
OSTI ID: 1418767
Report Number(s):
LA-UR-17-24854
Journal Information:
PLoS Biology (Online), Vol. 15, Issue 10; ISSN 1545-7885
Publisher:
Public Library of ScienceCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 12 works
Citation information provided by
Web of Science

References (63)

Prediction and measurement of an autoregulatory genetic module journal June 2003
Ultrasensitivity part II: multisite phosphorylation, stoichiometric inhibitors, and positive feedback journal November 2014
Bistability in cell signaling: How to make continuous processes discontinuous, and reversible processes irreversible journal January 2001
Noise Can Induce Bimodality in Positive Transcriptional Feedback Loops Without Bistability journal February 2010
P-TEFb kinase is required for HIV Tat transcriptional activation in vivo and in vitro journal October 1997
HIV Promoter Integration Site Primarily Modulates Transcriptional Burst Size Rather Than Frequency journal September 2010
Genetic Determinants and Cellular Constraints in Noisy Gene Expression journal December 2013
Variability in gene expression underlies incomplete penetrance journal February 2010
HIV Latency journal September 2011
The site of HIV-1 integration in the human genome determines basal transcriptional activity and response to Tat transactivation journal April 2001
Replication-Competent Noninduced Proviruses in the Latent Reservoir Increase Barrier to HIV-1 Cure journal October 2013
Mammalian Genes Are Transcribed with Widely Different Bursting Kinetics journal March 2011
An excitable gene regulatory circuit induces transient cellular differentiation journal March 2006
Exact stochastic simulation of coupled chemical reactions journal December 1977
Bimodal gene expression in noncooperative regulatory systems journal December 2010
From molecular to modular cell biology journal December 1999
Stochasticity in gene expression: from theories to phenotypes journal May 2005
Noise in protein expression scales with natural protein abundance journal May 2006
Accurate Chemical Master Equation Solution Using Multi-Finite Buffers journal January 2016
Robustness in simple biochemical networks journal June 1997
Stochastic Gene Expression in a Lentiviral Positive-Feedback Loop: HIV-1 Tat Fluctuations Drive Phenotypic Diversity journal July 2005
Single-cell transcriptomics reveals bimodality in expression and splicing in immune cells journal May 2013
Anti-termination of transcription within the long terminal repeat of HIV-1 by tat gene product journal December 1987
Gene network shaping of inherent noise spectra journal February 2006
High stimulus unmasks positive feedback in an autoregulated bacterial signaling circuit journal November 2008
A Hardwired HIV Latency Program journal February 2015
Green fluorescent protein is a quantitative reporter of gene expression in individual eukaryotic cells journal March 2005
Identification of a Reservoir for HIV-1 in Patients on Highly Active Antiretroviral Therapy journal November 1997
Stochastic Fate Selection in HIV-Infected Patients journal October 2013
Transcriptional burst frequency and burst size are equally modulated across the human genome journal October 2012
State Space Truncation with Quantified Errors for Accurate Solutions to Discrete Chemical Master Equation journal April 2016
Screening for noise in gene expression identifies drug synergies journal June 2014
Design Principles of Regulatory Networks: Searching for the Molecular Algorithms of the Cell journal January 2013
A minimal fate-selection switch journal December 2015
Robust, Tunable Biological Oscillations from Interlinked Positive and Negative Feedback Loops journal July 2008
An Evolutionary Role for HIV Latency in Enhancing Viral Transmission journal February 2015
Biological robustness journal November 2004
Frequency domain analysis of noise in autoregulated gene circuits journal April 2003
Transient-mediated fate determination in a transcriptional circuit of HIV journal March 2008
Feedback Loops Shape Cellular Signals in Space and Time journal October 2008
Transcriptional Bursting from the HIV-1 Promoter Is a Significant Source of Stochastic Noise in HIV-1 Gene Expression journal April 2010
Analytical distributions for stochastic gene expression journal November 2008
An HIV Feedback Resistor: Auto-Regulatory Circuit Deactivator and Noise Buffer journal December 2006
Noise in eukaryotic gene expression journal April 2003
Ultrasensitivity part I: Michaelian responses and zero-order ultrasensitivity journal October 2014
Cellular Decision Making and Biological Noise: From Microbes to Mammals journal March 2011
Regulation of noise in the expression of a single gene journal April 2002
Transient-mediated fate determination in a transcriptional circuit of HIV journal October 2007
Biological Robustness text January 2018
Gene network shaping of inherent noise spectra conference January 2006
Analytical distributions for stochastic gene expression text January 2008
Accurate Chemical Master Equation Solution Using Multi-Finite Buffers text January 2017
State space truncation with quantified errors for accurate solutions to discrete Chemical Master Equation text January 2017
And the Noise Played on: Stochastic Gene Expression and HIV-1 Infection journal July 2005
Transcription Factors Modulate c-Fos Transcriptional Bursts journal July 2014
Ultrasensitivity part III: cascades, bistable switches, and oscillators journal December 2014
Self-perpetuating states in signal transduction: positive feedback, double-negative feedback and bistability journal April 2002
Combining protein and mRNA quantification to decipher transcriptional regulation journal June 2015
Mammalian protein expression noise: scaling principles and the implications for knockdown experiments journal January 2012
Stochastic Kinetics of Nascent RNA journal September 2016
A Third-Generation Lentivirus Vector with a Conditional Packaging System journal November 1998
The Dip Test of Unimodality journal March 1985
Genetic Toggle Switch Without Cooperative Binding text January 2006

Cited By (6)

Post‐Transcriptional Noise Control journal June 2019
Probabilistic control of HIV latency and transactivation by the Tat gene circuit journal November 2018
Relatively slow stochastic gene-state switching in the presence of positive feedback significantly broadens the region of bimodality through stabilizing the uninduced phenotypic state journal March 2018
Kinetics of HTLV-1 reactivation from latency quantified by single-molecule RNA FISH and stochastic modelling journal November 2019
Self-Organization Controls Expression More than Abundance of Molecular Components of Transcription and Translation in Confined Cell-Free Gene Expression journal January 2018
Differences in Transcriptional Dynamics Between T-cells and Macrophages as Determined by a Three-State Mathematical Model journal February 2020