Ejection time of DNA

Range in vitro ≤10sec: into bacteria (E. coli) 5.2±4.2min
Organism Bacteriophage Lambda
Reference Van Valen D et al., A single-molecule Hershey-Chase experiment. Curr Biol. 2012 Jul 24 22(14):1339-43. doi: 10.1016/j.cub.2012.05.023. abstract, p.1339 right column 3rd paragraphPubMed ID22727695
Method P.1340 caption to figure 1:"(A) The DNA is stained while still in the capsid. During ejection, the phage DNA carries its complement of cyanine dye with it, transferring fluorescence intensity from the virus to the cellular interior. Eventually, the dye falls off the phage DNA and rebinds to the bacterium’s genome. (B) The timing of ejection is determined by measuring the loss of fluorescence intensity from the capsid: the concomitant increase in intensity in the cellular interior serves to verify that phage DNA has entered the cell."
Comments Abstract:"For bacteriophage λ, [investigators] establish a mean ejection time of roughly 5 min with significant cell-to-cell variability, including pausing events. In contrast, corresponding in vitro single-molecule ejections are more uniform and finish within 10 s." P.1339 right column 3rd paragraph:"The results of a number of ejection events for λcI60 are shown in Figure 3. For the measurements shown here, the viral-fluorescence decreases on a timescale of minutes, a factor of 10–100 times longer than the corresponding dynamics in vitro [refs 6, 7]. Here, the ejection time is the time required for 80% of the fluorescence intensity to leave the viral capsid. The mean and SD for the ejection time for λcI60 was 5.2±4.2 min (n = 45)."
Entered by Uri M
ID 112341