Transcriptional noise is a primary cause of the variability (noise) in gene expression occurring between cells in isogenic populations (see also cellular noise) .[1] A proposed source of transcriptional noise is transcriptional bursting[2][3][4] although other sources of heterogeneity, such as unequal separation of cell contents at mitosis are also likely to contribute considerably.[5] Bursting transcription, as opposed to simple probabilistic models of transcription, reflects multiple states of gene activity, with fluctuations between states separated by irregular intervals, generating uneven protein expression between cells. Noise in gene expression can have tremendous consequences on cell behaviour, and must be mitigated or integrated. In certain contexts, such as establishment of viral latency, the survival of microbes in rapidly changing stressful environments, or several types of scattered differentiation, the variability may be essential.[6][7] Variability also impacts upon the effectiveness of clinical treatment, with resistance of bacteria and yeast to antibiotics demonstrably caused by non-genetic differences.[8][9] Variability in gene expression may also contribute to resistance of sub-populations of cancer cells to chemotherapy [10] and appears to be a barrier to curing HIV.[11]

Notes

  1. ^ Raj, A; Van Oudenaarden, A (2008). "Nature, nurture, or chance: stochastic gene expression and its consequences". Cell. 135 (2): 216–26. doi:10.1016/j.cell.2008.09.050. PMC 3118044. PMID 18957198.
  2. ^ Golding, I; Paulsson, J; Zawilski, SM; Cox, EC (2005). "Real-time kinetics of gene activity in individual bacteria". Cell. 123 (6): 1025–36. doi:10.1016/j.cell.2005.09.031. PMID 16360033.
  3. ^ Chubb, JR; Trcek, T; Shenoy, SM; Singer, RH (2006). "Transcriptional pulsing of a developmental gene". Current Biology. 16 (10): 1018–25. doi:10.1016/j.cub.2006.03.092. PMC 4764056. PMID 16713960.
  4. ^ Raj, A; Peskin, CS; Tranchina, D; Vargas, DY; Tyagi, S (2006). "Stochastic mRNA synthesis in mammalian cells". PLOS Biology. 4 (10): e309. doi:10.1371/journal.pbio.0040309. PMC 1563489. PMID 17048983.
  5. ^ Huh, D.; Paulsson, J. (2010). "Non-genetic heterogeneity from stochastic partitioning at cell division". Nature Genetics. 43 (2): 95–100. doi:10.1038/ng.729. PMC 3208402. PMID 21186354.
  6. ^ Weinberger, L. S.; Burnett, J. C.; Toettcher, J. E.; Arkin, A. P.; Schaffer, D. V. (2005). "Stochastic gene expression in a lentiviral positive-feedback loop: HIV-1 Tat fluctuations drive phenotypic diversity". Cell. 122 (2): 169–82. arXiv:q-bio/0608002. doi:10.1016/j.cell.2005.06.006. PMID 16051143. S2CID 8061716.
  7. ^ Losick, R.; Desplan, C. (2008). "Stochasticity and cell fate". Science. 320 (5872): 65–68. Bibcode:2008Sci...320...65L. doi:10.1126/science.1147888. PMC 2605794. PMID 18388284.
  8. ^ Lewis, K. (2010). "Persister Cells". Annual Review of Microbiology. 64: 357–372. doi:10.1146/annurev.micro.112408.134306. PMID 20528688.
  9. ^ Blake, William J; Balázsi, Gábor; Kohanski, Michael A; Isaacs, Farren J; Murphy, Kevin F; Kuang, Yina; Cantor, Charles R; Walt, David R; Collins, James J (2006). "Phenotypic Consequences of Promoter-Mediated Transcriptional Noise". Molecular Cell. 24 (6): 853–865. doi:10.1016/j.molcel.2006.11.003. PMID 17189188.
  10. ^ Sharma, S. V.; Lee, D. Y.; Li, B.; Quinlan, M. P.; Takahashi, F.; Maheswaran, S.; McDermott, U.; Azizian, N.; Zou, L.; Fischbach, M. A.; Wong, K. K.; Brandstetter, K.; Wittner, B.; Ramaswamy, S.; Classon, M.; Settleman, J. (2010). "A chromatin-mediated reversible drug tolerant state in cancer cell subpopulations". Cell. 141 (1): 69–80. doi:10.1016/j.cell.2010.02.027. PMC 2851638. PMID 20371346.
  11. ^ Weinberger, A. D.; Weinberger, L. S. (2013). "Stochastic fate selection in HIV-infected patients". Cell. 155 (3): 497–9. doi:10.1016/j.cell.2013.09.039. PMID 24243007.
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