New research on how bacteria make compounds critical to their survival may help scientists create antibiotics for controlling dangerous bacterial pathogens, say scientists in the October issue of the Proceedings of the National Academy of Sciences.
For decades, scientists believed that gene regulation in bacteria depended only on regulatory proteins. New findings, however, have altered those beliefs. Researchers found that bacteria use RNA to directly measure a signal and to control the related genes, rather than using a messenger protein to send information to the gene.
Researchers at The Ohio State University, Columbus, looked at how Bacillus subtilis, a harmless bacterium, makes the amino acid lysine. Lysine is a crucial ingredient in making protein and in building bacterial cell walls.
Researchers conducted their experiments on B. subtilis in the laboratory to look for the mechanism that the bacteria uses to control the production of lysine.
"Cells are really smart—they only make what they need," said Tina Henkin, Ph.D., the study’s lead author and a professor of microbiology. "In this case, if there’s enough lysine in the environment that they can use, or if they’ve already made as much as they need, the RNA binds the lysine, and turns off the lysine synthesis genes so they won’t make more. If they need lysine, however, the lysine-making genes are turned on.
"This is a way of controlling gene expression that scientists didn’t know existed," Dr. Henkin continued. "Everybody assumed that this kind of intra-cellular communication must need a regulatory protein in order to work. The gene that regulates lysine production in B. subtilis evolved its own communication system without needing to talk to a protein.
"By studying nonpathogens with structures and functions similar to those of pathogenic bacteria, we’re learning how disease-causing bacteria control their most vital physiological functions," Dr. Henkin said. "We want to use the information we gain to understand how these kinds of pathogens behave and how they control their own genes, which could help in developing antibiotics for some of medicine’s worst enemies. We are quickly running out of effective antibiotics, as the bacteria develop resistance to the ones we have."
