Usually indigestion is a bad thing, but experiments by researcher Peter Chien and graduate student Robert Vass at the University of Massachusetts Amherst recently showed that for the bacteria Caulobacter crescentus, partial degradation of a DNA replication protein is required to keep it alive.
DNA replication is one of the most highly controlled biological processes in all organisms, says Chien, an assistant professor of biochemistry and molecular biology at UMass Amherst. From humans all the way back to bacteria, all cells must faithfully duplicate their genomes in order to survive. To coordinate the start, ensure the completion and repair damages during DNA replication, specialized proteins play a key role by regulating processes.
In work published this month in Proceedings of the National Academy of Sciences, Chien and Vass report that one of these specialized replication factors, DnaX, is, to their surprise, partially digested or trimmed, physically cut into shorter fragments, by an energy-dependent protease known as ClpXP, which generates specific-sized fragments that are essential for Caulobacter's normal growth.