Jy. Bouet et al., THE EFFECTS ON ESCHERICHIA-COLI OF EXPRESSION OF THE CLONED BACTERIOPHAGE-T4 NUCLEOID DISRUPTION (NDD) GENE, Molecular microbiology, 20(3), 1996, pp. 519-528
Immediately after T4 bacteriophage infection, the Escherichia coli nuc
leoid undergoes rapid delocalization. The ndd gene of T4 is responsibl
e for this nuclear disruption phenomenon. We have cloned two alleles o
f this gene and studied the effects of their expression on E. coli cel
ls. We have shown that the Ndd protein (i) is able to reproduce the di
sruption of the nucleoid characteristic of T4 infection, (ii) is highl
y toxic and results in a logarithmic decrease in cell viability, and (
iii) inhibits genomic DNA replication by blocking progression of repli
cation forks. Induction of Ndd does not result in degradation of genom
ic DNA and does not significantly alter the general processes of trans
cription and translation during the entire period of exponential cell
death. These results support the notion that the target of Ndd is some
aspect of the nucleoid architecture.