Identification of a high-copy-number plasmid suppressor of a lethal phenotype caused by mutant DnaA protein which has decreased intrinsic ATPase activity
M. Makise et al., Identification of a high-copy-number plasmid suppressor of a lethal phenotype caused by mutant DnaA protein which has decreased intrinsic ATPase activity, BIOL PHAR B, 22(9), 1999, pp. 904-909
The induction of a mutant DnaA protein (DnaA E204Q) with decreased intrinsi
c ATPase activity in cells causes a lethal phenotype, Eased on our results
that the decreased ATPase activity of DnaA E204Q is activated to the level
of a wild-type protein in the presence of partially purified stimulating fa
ctors for DnaA ATPase, we tested the hypothesis that genes encoding the sti
mulating factors can be cloned as high-copy-number plasmid suppressors for
the lethality caused by DnaA E204Q. We isolated a number of high copy-numbe
r plasmids that suppress the lethal phenotype. The genes responsible for th
e suppression of the lethal phenotype were revealed to be dnaN, relA, pcnB
and cyaA by subcloning, and a site-directed mutational analysis. The mechan
isms by which these genes suppressed the lethal phenotype were examined in
vivo and in vitro.