The diversity of activity among guide RNAs
The guide RNA activity distributions of negative control(selective1) and
screening experiment(selective2) were shown (Fig.1c). As there is almost
no selection pressure of DNA cleavage, the guide RNA activity in the SE1
nearly obeyed a normal distribution with mean approximately equal to 1
as expected, while in SE2 there was significant variability of guide RNA
activities. Concretely, the majority of guide RNAs in the designed
library exhibited high activities that the best of which resulted in
1000-fold slowdown in growth rate of E. coli cells. To validate such
results from the screening experiment, we chose a series of guide RNAs
consisting of 9 with high scores and 2 with low scores to retest their
activities individually by measuring colony number after transformation,
and the results were observed in a very good consistency with which in
the screening experiment (Fig.1d). Thus, it suggested that our screening
method to evaluate guide RNA activity was reliable and such activity
dataset could be used for further analysis.