Zusammenfassung
TrfA is the only plasmid-encoded protein required for RK2 replication.
We report here the construction and characterization of an RK2-based
vector in which trfA is expressed from the inducible promoter Pm.
The resulting construct, pJBSD1, was found to replicate in Escherichia
coli DH5a (recA(-)) only in the presence of a Pm inducer. In two
tested E. coli recA(+) strains pJBSD1 could replicate in the absence
of inducer, but a replication inducer-dependent phenotype was obtained
in these strains by introducing a mutation known to reduce the trfA
expression level. The plasmid construct could be used as a conditional
suicide vector system for targeted chromosomal integration via homologous
recombination. This feature may potentially be used for many types
of studies in microbial molecular biology.
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