COLUMBUS, Ohio The results of a new study suggest that bacteria that cause diseases like bubonic plague and serious gastric illness can turn the genes that make them infectious on or off.
Knowing how disease-causing bacteria, like Yersinia pestis and E. coli, do this may one day help scientists create drugs that control the expression of these genes, thereby making the bacteria harmless, said Vladimir Svetlov, a study co-author and a research associate in microbiology at Ohio State University. The findings appear in the April 13 issue of the journal Molecular Cell.
Gene expression the process of turning on, or activating, genes is controlled by proteins called transcription factors. Every type of bacteria known to humankind contains the transcription factor NusG, which controls nearly all of a bacterium's gene expression. Without it, a microorganism will die.
We think that NusG regulates nearly every gene in every form of bacteria, said Irina Artsimovitch, the study's lead author and an associate professor of microbiology at Ohio State . Say a bacterium has 3,000 genes NusG would regulate 2,900 of them.
But somewhere along the evolutionary path, NusG was copied and physically changed. The result was a specialized transcription factor called RfaH. Unlike NusG, RfaH controls only a small portion of gene expression. But it happens to turn on those genes that give bacteria like E. coli and Y. pestis their ability to infect.
The researchers say that this study likely marks the first successful attempt by a laboratory to determine the structure of RfaH.
They used special X-ray techniques to study and describe RfaH proteins that they had extracted from E. coli. They found that while about two-thirds of RfaH's structure closely resembles the structure of NusG, the remaining one-third looked dramatically different. It's this latter third that appears to be the portion of the protein responsible for controllin
Contact: Vladimir Svetlov
Ohio State University