TY - JOUR
T1 - Regulation of chromosomal replication by DnaA protein availability in Escherichia coli
T2 - effects of the datA region
AU - Morigen, null
AU - Boye, E
AU - Skarstad, K
AU - Løbner-Olesen, A
PY - 2001/10/31
Y1 - 2001/10/31
N2 - Initiation of chromosomal replication in Escherichia coli is dependent on availability of the initiator protein DnaA. We have introduced into E. coli cells plasmids carrying the chromosomal locus datA, which has a high affinity for DnaA. To be able to monitor oriC initiation as a function of datA copy number, we introduced a minichromosome which only replicates from oriC, using a host cell which replicates its chromosome independently of oriC. Our data show that a moderate increase in datA copy number is accompanied by increased DnaA protein synthesis that allows oriC initiation to occur normally, as measured by minichromosome copy number. As datA gene dosage is increased dnaA expression cannot be further derepressed, and the minichromosome copy number is dramatically reduced. Under these conditions the minichromosome was maintained by integration into the chromosome. These findings suggest that the datA locus plays a significant role in regulating oriC initiation, by its capacity to bind DnaA. They also suggest that auto regulation of the dnaA gene is of minor importance in regulation of chromosome initiation.
AB - Initiation of chromosomal replication in Escherichia coli is dependent on availability of the initiator protein DnaA. We have introduced into E. coli cells plasmids carrying the chromosomal locus datA, which has a high affinity for DnaA. To be able to monitor oriC initiation as a function of datA copy number, we introduced a minichromosome which only replicates from oriC, using a host cell which replicates its chromosome independently of oriC. Our data show that a moderate increase in datA copy number is accompanied by increased DnaA protein synthesis that allows oriC initiation to occur normally, as measured by minichromosome copy number. As datA gene dosage is increased dnaA expression cannot be further derepressed, and the minichromosome copy number is dramatically reduced. Under these conditions the minichromosome was maintained by integration into the chromosome. These findings suggest that the datA locus plays a significant role in regulating oriC initiation, by its capacity to bind DnaA. They also suggest that auto regulation of the dnaA gene is of minor importance in regulation of chromosome initiation.
KW - Bacterial Proteins/chemistry
KW - Chromosomes, Bacterial/physiology
KW - DNA Replication
KW - DNA-Binding Proteins/chemistry
KW - Escherichia coli/genetics
KW - Gene Expression Regulation, Bacterial
KW - Plasmids
M3 - Journal article
C2 - 11690638
SN - 0304-419X
VL - 1521
SP - 73
EP - 80
JO - Biochimica et Biophysica Acta - Reviews on Cancer
JF - Biochimica et Biophysica Acta - Reviews on Cancer
IS - 1-3
ER -