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 New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>