Scientists Identify Protein Family that Helps Maintain Genome Stability

Researchers from the University of Montreal in Canada led by Normand Brisson have identified a family of protein that protects the genome from harmful mutations. Called the whirlies, because of their peculiar structure similar to a whirligig, the protein family was shown by Brisson to be key in preventing major rearrangements of genes that could result in the creation of multiple gene copies. These proteins are involved in a variety of phenomena, including pathogen defense.

The University of Montreal researchers studied the role whirlies play in keeping the stability of the plastid genome in Arabidopsis. Results of their study appear in a paper published by PNAS. They found that whirly proteins bind single stranded DNA molecules and function as antirecombination proteins, contributing to safeguard plastid genome integrity. Silencing of genes that code for the whirly proteins resulted to plants with variegated green-white leaves, symptomatic of nonfunctional chloroplasts.

Whirlies do not only protect the genome from dangerous alterations, it could also allow some useful mutations to occur, the researchers found. "Such mutations played an important role in the evolution of plants with high nutritional value, resistance to disease and harsh climate that are so important to modern agriculture," said Brisson. "Our results open new research avenues for the study of similar mechanisms of gene repair in humans that might be important for human evolution, our responses to stress and the prevention of devastating diseases."

The paper published by PNAS is available at http://dx.doi.org/10.1073/pnas.0901710106 For more information, read http://www.nouvelles.umontreal.ca/udem-news/press-releases/evolution-coup-study-reveals-how-plants-protect-their-genes.html