Scientists make fundamental discovery about how gene expression functions in bacteria

Apr 22, 2010

Researchers from NYU Langone Medical Center have discovered and characterized a general mechanism that controls transcription elongation in bacteria. The mechanism, described in the April 23 issue of Science, relies on physical cooperation between a moving ribosome and RNA polymerase (RNAP) that allows for a precise adjustment of the transcriptional yield in response to translational needs. The study could lead to the development of new ways to interfere with bacterial gene expression and serve as a new target for antimicrobial therapy.

"The finding that the active controls the rate of transcription at every protein-coding gene and under various growth conditions was quite unexpected - and the results are far reaching," says Evgeny Nudler, PhD, the Julie Wilson Anderson Professor of Biochemistry at NYU Langone Medical Center and lead author of the study. "It appears that the ribosome not just moves behind RNAP while translating the nascent transcript, but it is actually able to 'push' the paused or arrested RNAP molecules forward, thereby accelerating RNAP speed and also helping RNAP to traverse road blocks imposed by DNA binding proteins."

In the study, Nudler and colleagues demonstrate that the rate of transcription elongation perfectly matches the rate of translation under various growth conditions. They also show that the transcription rate depends on codon usage, or the frequency of rare codons which modulates the speed of a ribosome. Finally, the authors illustrate that it is the speed of the ribosome that determines the speed of RNAP -- whereby the acceleration or deceleration of a ribosome by chemical or leads to corresponding changes in RNAP speed.

Transcription and translation are the two principle events in the pathway of converting the into proteins. The data shows that these two events are tightly coupled, and cannot proceed efficiently without each other. Thus, uncoupling these processes, by breaking the proposed physical linkage between RNA and polymerase and the ribosome, could be a new way to disrupt bacterial gene expression and serve as a new target for antimicrobial therapy.

The implications of the study are important because it could lead to the development of novel ways to disrupt and the creation of new antimicrobial therapies. Not only does this cooperation mechanism save energy by limiting any excessive transcripts that cannot be translated in a timely manner, but it also prevents premature transcription termination by Rho factor, ensuring continuous coupling between transcription and translation. Thus, bacteria rely on macromolecule trafficking and cooperation, a fundamentally novel mechanism, to finely control expression of each individual gene in response to nutrient availability and growth phase.

Explore further: Project launched to study evolutionary history of fungi

Related Stories

Rewrite the textbooks: Transcription is bidirectional

Jan 25, 2009

Genes that contain instructions for making proteins make up less than 2% of the human genome. Yet, for unknown reasons, most of our genome is transcribed into RNA. The same is true for many other organisms that are easier ...

Backtracking on DNA

Jun 23, 2009

(PhysOrg.com) -- Accuracy is essential for life, so in converting the information stored in DNA into a form in which it can be used, a high level of precision is required. Dr Tanniemola Liverpool from the ...

Recommended for you

Project launched to study evolutionary history of fungi

55 minutes ago

The University of California, Riverside is one of 11 collaborating institutions that have been funded a total of $2.5 million by the National Science Foundation for a project focused on studying zygomycetes – ancient li ...

Different watering regimes boost crop yields

4 hours ago

Watering tomato plants less frequently could improve yields in saline conditions, according to a study of the impact of water and soil salinity on vegetable crops.

Woolly mammoth genome sequencer at UWA

5 hours ago

How can a giant woolly mammoth which lived at least 200,000 years ago help to save the Tasmanian Devil from extinction? The answer lies in DNA, the carrier of genetic information.

Battling superbugs with gene-editing system

23 hours ago

In recent years, new strains of bacteria have emerged that resist even the most powerful antibiotics. Each year, these superbugs, including drug-resistant forms of tuberculosis and staphylococcus, infect ...

User comments : 0