The gene is probably not solely responsible for the bacterium's remarkable restorative powers, says Earl. "We are not exactly sure how it functions in relation to other regulatory genes. It could serve as anything from a damage sensor to something that directly controls gene expression. All we really know is the bacterium cannot survive radiation or other types of damage without it."
Earl and her colleagues are currently working on identifying which cellular functions irrE controls. "In defining which genes irrE controls, we can better focus our attention to a small subset of genes that are most important to D. radiodurans response to radiation damage," she says.