Construction and Synchronization of dnaA Temperature-Sensitive Mutants of Streptomyces

Temperature-sensitive mutants of Streptomyces defective in initiation of chromosome replication were created by in vitro site-directed mutagenesis in the dnaA gene followed by gene replacement. When they were shifted to 39°C replication in the mutants ceased in about 90 min but resumed on return to 30°C. This allowed manipulations to achieve replication synchronization.