Functional analysis of pSM19035-derived replicons in Bacillus subtilis

Abstract: We determined the effect of various Bacillus ubtilis dna(Ts) mutations on pSM19035 replication. At non-permissive temperature, plasmid replication depends on the naB, dnaC, dnaG nd dnaI initiation replication products, bu does not require the dnaA function. DNA elongation is performed by DNA polymerase III, since replication is blocked at non-permissive temperature in d a(Ts) mutants impaired in different subunits of the enzyme. Single-stranded plasmid replication intermediates, corresponding to the leading strand, accumulate in the d aD strain. On the basis of electron microscopic analysis of replication intermediates, we confirmed that the plasmid replicates unidirectionally by a theta mechanism. Key words: Bacillus; Replication mutant strains, incompatibility group 18