Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Basic work on E. coli identifies two new keys to regulation of bacterial gene expression

20.06.2006
The cellular process of transcription, in which the enzyme RNA polymerase constructs chains of RNA from information contained in DNA, depends upon previously underappreciated sections of both the DNA promoter region and RNA polymerase, according to work done with the bacterium E. coli and published today (June 16) in the journal Cell by a team of bacteriologists from the University of Wisconsin-Madison.

This fundamental research about a key step in RNA synthesis has important implications for the study of gene expression in other organisms, and adds to the wealth of knowledge about E. coli contributed by scientists from the UW-Madison.

"The kinds of processes that we study in E. coli happen in a wide variety of bacteria of medical, environmental and agricultural importance," notes Rick Gourse, a professor of bacteriology who published the Cell paper along with a team from his lab. "This knowledge can ultimately be put to use in systems that aren't so amenable to investigation, such as bacteria that cause cholera, produce anthrax toxin or lead to ulcers and stomach cancer."

Scientists use model organisms because they are relatively easy to work with and because there is a vast amount of previous knowledge about them. They can then test whether their findings in model organisms hold true in other species, says Gourse, who studies a strain of E. coli that while harmless, is closely related to disease-causing varieties like E. coli 0157:H7.

"Basic research in E. coli is very important," says Gourse. "Much of what we know about gene expression both in bacteria and in higher life forms comes from work performed originally on this model organism." The strain that Gourse works with is one of the most well-studied species in biology and has important ties to the UW-Madison.

In his most recent study, Gourse investigated the interaction between RNA polymerase and promoters from the E. coli chromosome. RNA polymerase reads the information in DNA and transcribes it into chains of RNA, which are later translated into proteins. Promoter regions are specific sequences within the DNA chain that tell RNA polymerase when and where to begin transcription, and how much product to make from specific genes.

Gourse's group found that there is a specific region within DNA promoters that makes contact with a highly conserved but previously underappreciated segment of the sigma subunit of RNA polymerase. While the contact with sigma is very strong at promoters for most genes, it is particularly weak at promoters that make ribosomal RNA, which means that other factors like nutritional and environmental signals ultimately regulate the expression of those genes.

"In this case, regulation is achieved not because the promoter makes a special contact, but because it can't establish contact at all," says Gourse. "This is an example of how sometimes less is more, and a probably very ancient example of one of the methods that arose through evolution to regulate gene expression."

Ribosomal RNA makes up the bulk of ribosomes, the molecular machines that make proteins and are present in huge numbers in all cells. Since so much of the cell's energy is used to make ribosomes, control of ribosomal RNA transcription is particularly crucial to a cell's well-being.

"This work is basic to the growth of all bacteria," says Gourse. "By understanding transcription and control of ribosome synthesis in E. coli, we can understand more about these processes in bacterial species that we need to control, like those that cause disease or make toxins. E. coli is also the workhorse of the biotechnology industry. Understanding E. coli gene expression in detail allows us to harness these cells for producing products of biotechnological importance, like pharmaceuticals."

Gourse's work was supported by the National Institutes of Health, the United States Department of Agriculture, and by Pfizer Biotechnology. His team included graduate student Shanil Haugen; undergraduate Christopher Ward; and senior scientists Wilma Ross and Tamas Gaal.

Richard Gourse | EurekAlert!
Further information:
http://www.wisc.edu

More articles from Life Sciences:

nachricht Making fuel out of thick air
08.12.2017 | DOE/Argonne National Laboratory

nachricht ‘Spying’ on the hidden geometry of complex networks through machine intelligence
08.12.2017 | Technische Universität Dresden

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

PhoxTroT: Optical Interconnect Technologies Revolutionized Data Centers and HPC Systems

11.12.2017 | Information Technology

Large-scale battery storage system in field trial

11.12.2017 | Power and Electrical Engineering

See, understand and experience the work of the future

11.12.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>