Single-Cell Biophysics: Measurement, Modulation, and Modeling

Single-Cell Biophysics: Measurement, Modulation, and Modeling

Sunday Speaker Abstracts

Direct Observation of Transcription in a Living Bacterial Cell

Nam Ki Lee

Seoul National University, Seoul, South Korea.

Transcription, a process of mRNA generation by RNA polymerase (RNAP), is highly coupled

with translation by ribosome in bacteria. The effect of the transcription-translation coupling on

the transcriptional dynamics and the localization of genes in a living cell is poorly understood.

Here, we directly observe the dynamics of transcription and the movement of the subcellular

localization of genes actively transcribed by RNAP in living cells at the sub-diffraction limit

resolution. The subcellular localizations of the non-membrane protein’ genes, actively

transcribed by RNAPs, move toward outside nucleoid or to plasma membrane by the effect of

translation by ribosome. The movement of genes by transcription-translation coupling is general

for both E. coli RNAP and T7 RNAP. Importantly, the subcellular movement of the gene is

coupled with the enhancement of the transcription initiation rate, which is to a certain extent

analogous to the chromatin decondensation in eukaryotes. Our observation demonstrates how

two spatially separated processes of transcription and translation are coupled in bacteria and the

movement of genes by the cooperation between transcription and translation plays a crucial role

in the effective expression of genes in E.coli.