Involvement of host DNA gyrase in growth of bacteriophage T5

Abstract

Bacteriophage T5 did not grow at the nonpermissive temperature of 42°C in Escherichia coli carryipg a temperature-sensitive mutation in gyrB [gyrB(Ts)], but it did grow in gyrA(Ts) mutants at 42°C. These findings indicate that the A subunit of host DNA gyrase is unnecessary, whereas the B subunit is necessary for growth of T5. The necessity for the B subunit was confirmed by a strong inhibition of T5 growth by novobiocin and coumermycin A1, which interfere specifically with the function of the B subunit of host DNA gyrase. However, T5 growth was also strongly inhibited by nalidixic acid, which interferes specifically with the function of the A subunit. This inhibition was due to the interaction of nalidixic acid with the A subunit and not just to its binding to DNA, because appropriate mutations in the gyrA gene of the host conferred nalidixic acid resistance to the host and resistance to T5 growth in such a host. The inhibition by nalidixic acid was also not due to a cell poison formed between nalidixic acid and the A subunit (K. N. Kreuzer and N. R. Cozzarelli, J. Bacteriol. 140:424-435, 1979) because nalidixic acid inhibited growth of T5 in a gyrA(Ts) mutant (KNK453) at 42°C. We suggest that T5 grows in KNK453 at 42°C because its gyrA(Ts) mutation is leaky for T5. Inhibition of T5 growth due to inactivation of host DNA gyrase was caused mainly by inhibition of T5 DNA replication. In addition, however, late T5 genes were barely expressed when host DNA gyrase was inactivated.

Involvement of topoisomerases in replication, transcription, and packaging of the linear adenovirus genome

“…Electron microscopic evidence for the presence of topologically constrained DNA loops in intracellular adenovirus DNA. The results obtained with the topoisomerase inhibitors suggest that intracellular adenovirus DNA templates are topo- 4. Southern blot analysis of single-and double-strand cleavages of AdS DNA induced by camptothecin.…”

“…and T7 phages, the replication of phage DNA and the expression of certain phage genes require host gyrase activity (4,5,13,29). Bacillus subtilis bacteriophage SPOl, which contains a linear double-stranded genome, also requires host gyrase activity for replication (1).…”

“…Topological problems of DNA are usually associated with covalently closed circular DNA, in which the two strands of the double helix are topologically linked. However, a number of bacteriophages and animal viruses with linear double-stranded DNA genomes have been shown to require either host or viral topoisomerases in their life cycles (1,2,4,5,13,15,20). These observations indicate that DNA topology also plays an important role in linear genomes which may be arranged in different topological forms through DNA-protein interactions inside the cells.…”

A bacteriophage tubulin harnesses dynamic instability to center DNA in infected cells

“…We therefore sought to test whether replication was required, directly or indirectly, for phage DNA movement. At various points during infection we added a potent DNA gyrase inhibitor (ciprofloxacin) that blocks replication of DNA in a broad spectrum of bacteria, plasmids and phage ( Alonso et al, 1981 ; Constantinou et al, 1986 ; Fisher et al, 1989 ). While ciprofloxacin reduced phage nucleoid size as expected, indicating a reduced accumulation of DNA ( Figure 8A ), it had no effect on its positioning at midcell, suggesting that DNA replication was not required for the centering function of the PhuZ spindle ( Figure 8B ).…”

Using Bacteriophages as a Trojan Horse to the Killing of Dual-Species Biofilm Formed by Pseudomonas aeruginosa and Methicillin Resistant Staphylococcus aureus

“…Indeed, when we analyzed by calorimetry the exposure of dual-species biofilms to ciprofloxacin and PYO or PYO+Sb-1 simultaneously, we observed a paradoxical effect, where lower concentrations of ciprofloxacin in combination with phages showed a higher delay/decrease in heat flow production compared to higher antibiotic concentrations. We assume that the mode of action of ciprofloxacin inhibiting bacterial DNA replication might hamper the phage amplification (replication) (Constantinou et al, 1986). Therefore, lower doses of ciprofloxacin could have a minor interference with phage replication or could not reduce the concentration of bacteria to levels below which phages can replicate, if compared to higher antibiotic doses (Levin et al, 1977).…”