TY - JOUR
T1 - ppGpp-mediated regulation of DNA replication and cell division in Escherichia coli
AU - Schreiber, Gideon
AU - Ron, Eliora Z.
AU - Glaser, Gad
PY - 1995/1
Y1 - 1995/1
N2 - ppGpp serves as an alarmon in prokaryotes, distributing and coordinating different cellular processes according to the nutritional potential of the growth medium. This work is interpreted as favoring the view that, in addition to its previously documented role in regulating the rate of ribosome synthesis [4], ppGpp participates in coordinating DNA replication and cell division. We studied the effects of ppGpp on the cell division cycle, using cells containing plasmid pSM11 that codes for the 55-kDa truncated RelA protein under the inducible Ptac promoter. In this system it was found that the rate of initiation of new rounds of DNA replication is inversely correlated with the intracellular level of ppGpp. Furthermore, ppGpp levels similar to those found during the activation of stringent control inhibited replication initiation, in a manner comparable to that resulting from inhibition of protein synthesis by amino acid starvation or by chloramphenicol addition. However, in contrast to chloramphenicol treatment, elevated ppGpp levels did not block septum formation, and, in fact, there is some evidence for enhanced septation. As a result, the residual cell division following elevation in ppGpp levels was higher than after chloramphenicol treatment, resulting in cells with a size similar to that of stationary phase cells.
AB - ppGpp serves as an alarmon in prokaryotes, distributing and coordinating different cellular processes according to the nutritional potential of the growth medium. This work is interpreted as favoring the view that, in addition to its previously documented role in regulating the rate of ribosome synthesis [4], ppGpp participates in coordinating DNA replication and cell division. We studied the effects of ppGpp on the cell division cycle, using cells containing plasmid pSM11 that codes for the 55-kDa truncated RelA protein under the inducible Ptac promoter. In this system it was found that the rate of initiation of new rounds of DNA replication is inversely correlated with the intracellular level of ppGpp. Furthermore, ppGpp levels similar to those found during the activation of stringent control inhibited replication initiation, in a manner comparable to that resulting from inhibition of protein synthesis by amino acid starvation or by chloramphenicol addition. However, in contrast to chloramphenicol treatment, elevated ppGpp levels did not block septum formation, and, in fact, there is some evidence for enhanced septation. As a result, the residual cell division following elevation in ppGpp levels was higher than after chloramphenicol treatment, resulting in cells with a size similar to that of stationary phase cells.
UR - http://www.scopus.com/inward/record.url?scp=0028960079&partnerID=8YFLogxK
U2 - 10.1007/BF00294520
DO - 10.1007/BF00294520
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
C2 - 7765879
AN - SCOPUS:0028960079
SN - 0343-8651
VL - 30
SP - 27
EP - 32
JO - Current Microbiology
JF - Current Microbiology
IS - 1
ER -