Department of Bacteriology, University of Wisconsin-Madison, 420 Henry Mall, Madison, WI 53706, USA. rgourse@bact.wisc.edu
The bacterial signaling molecules ppGpp and pppGpp regulate transcription initiation in response to starvation by altering RNA polymerase activity. In this issue, Wang et al. (2007) show that (p)ppGpp also inhibits DNA replication elongation by interfering with DNA primase activity. Halting replication may help cells to maintain genomic integrity during periods of transient nutrient limitation.