Stochastic nature of phage promoter switching


Measurement of gene expression in vivo must take into consideration factors of single cell heterogeneity, multiple gene copies, and stochastic variation in promoter occupancy.  CPLC researcher I. Golding and colleagues have examined this problem in the phage lambda lysogeny maintenance promoter system in individual E. coli cells.   Simultaneous single-cell measurements were taken of the phage repressor concentration as well as the number of individual messenger RNAs.  A mathematical model was developed to describe stochastic activity in this promoter.  The model showed that switching between promoter configurations occurred faster than the lifetime of mRNA molecules produced, and individual copies of the same gene functioned independently within same cell. Thus, simultaneous in vivo quantification of transcription factor and promoter activity followed by stochastic theoretical analysis is a tool that can provide new information on well-studied genetic circuits.

Read more at Sepúlveda, L.A., et al. (2016) Science 351(6278):1218-1222.



The Scientist (Midland, Ontario, Jan. 20) -- John Rogers, a professor of materials science and engineering at Illinois, and his colleagues have constructed flexible energy-harvesting devices that can convert the movement of body parts – such as the heart and lungs – into energy captured by a battery that could be used to power implantable devices like pacemakers. Also: CNET News (San Francisco), Gizmodo India (New Delhi, Jan. 20), New Scientist (Cambridge, England, Jan. 20), News Track India (from Asian News International, Washington, D.C.; New Delhi, Jan. 21), HealthDay (Jan. 21), CBS News (Jan. 21), ASEE FirstBell (Jan. 22), The Philadelphia Inquirer (from HealthDay News, Jan. 21), CNET Asia (Centrepoint, Singapore, Jan. 21), The Hindiu (Jan. 22), Popular Mechanics (Jan. 21), Authint Mail (Jan. 22), Medical Daily (Jan. 21), Chemistry World (Jan. 22), Voice of America (Jan. 22), Science 360 (NSF, from Popular Mechanics, Jan. 23), CNET News (San Francisco, Jan. 23), Red (Dallas, Jan. 26), Energy Harvesting Journal (Cambridge, Mass., Jan. 27), New Zealand Herald (Auckland, Jan. 28), (Bristol, England, Jan. 31), Daily Fusion (New York City, Feb. 5).