I hope you will pardon the delay but I have been so rushed that I did not get the time really to get the necessary tracings
done so that you can get an idea of the data. It turned out that verifax copies of our results as we plot them was too confusing.
We, therefore made tracings of the data so that you could see them. I have given you only some of the experiments and representative
runs. Figures 1a and 1b illustrate the kind of discrepancy one observes as a result of the induction of an ordinary wild
type. They represent Hershey columns of mixed RNA from cells treated according to the diagrammatic protocol on top of each.
In all cases the dotted lines represents optical density profile and represents the bulk of the RNA components. The green
is always tritiated preparation and the red is the C14. The gradient is indicated by a dashed pencil line. 1a is a control
run in which neither one was induced. You see that there is good concordance between the two profiles. In figure 1b the
tritiated preparation came from a cell induced. The C14 was uninduced. You will notice then two discordant peaks in the
tritium profile. Another control is given in figure 2 in which a lac deletion mutant was induced and not induced. Here induction
had no effect.
These results are completely reproducible and have been obtained many times. We have a fairly detailed story on the kinetics
of the appearance of these discordancies during the induction of a wild type. The regions of interest in figure 1 were arbitrarily
designated and the fractions within each pooled. Figures 2a, b, and c represent cesium chloride gradient runs of hybridizing
experiments carried out with a P1 carrying lac. It is clear the region two contains the most hybridizable material. The
amounts of counts put in each were approximately the same. Here, as in all other cases, we are only looking at the RNA resistant
counts. 3a and 3b represent the two types of controls. Here the same region from a labeled induced deletion negative shows
no ability to hybridize with the P1 carrying lac. 3b shows that the same region in the gradient taken from an uninduced wild
type inducible shows a faintly detectable possible hybrid. It is clear from comparison with 3a and 3b that induction leads
to the onset of transcription. Figures 4a and 4b represent the other types of controls in which region 2 again was mated
with the P1 DNA not carrying lac and there is virtually no detectable hybrid. 4b checks the same thing with RNA from and
non-induced wild type again from the same region. Again, there is no hybrid.
I might say that we have also looked at other regions of figure 1b for hybridizable RNA with the P1 carrying lac and the results
have been negative. We are now running a few matings with unfractionated RNA as a final check. Also there are a few other
repeat controls which are spinning now and if everything checks out I think we can regard the story as established.