Speaker
Prof.
Andre S. Ribeiro
(TUT)
Description
Recent developments of single molecule detection techniques
have made possible to observe transcription and translation,
one event at a time, in live cells. Here, we report
measurements of time intervals between consecutive
transcription events from several promoters in live
Escherichia coli cells, which were obtained using a
single-RNA detection technique by MS2-GFP tagging. From
these, we show that, surprisingly, the kinetics of
production of transcripts is consistent with multi-step,
sub-Poissonian process for all promoters tested. Next, we
report recent measurements of the waiting time for the
production of the first RNA under the control of PBAD
promoter following induction by arabinose. These provide the
first direct estimation of the contribution of intake times
of inducers by the cells to the cell to cell diversity in
RNA numbers. We find that the kinetics of the arabinose
intake system affects mean and diversity in RNA numbers,
long after induction. We observed the same effect on
Plac/ara-1 promoter, inducible by arabinose or IPTG.
Importantly, the distribution of waiting times of Plac/ara-1
is indistinguishable from that of PBAD, if and only if
induced by arabinose alone. We conclude that
inducer-dependent waiting times affect mean and cell-to-cell
diversity in RNA numbers long after induction, suggesting
that intake mechanisms have non-negligible effects on the
phenotypic diversity of cell populations in natural,
fluctuating environments.
Primary author
Prof.
Andre S. Ribeiro
(TUT)
