Isolation of genes preferentially expressed during Bacillis subtilis spore outgrowth

From the Charon 4A library of Ferrari et al (J. Bacteriol. 146:430-432, 1981) we isolated three genes involved in Bacillus subtilis spore outgrowth by screening the library by hybridization with labeled RNA from outgrowing spores in the presence of an excess of unlabeled vegetative RNA. Hybridization competition experiments with purified clones showed that the clones contained sequences that were transcribed only during spore outgrowth or preferentially during spore outgrowth. Fragments of the cloned DNAs were subcloned in plasmid pJH101, and by using plasmid integration and PBS1 transduction the chromosomal loci were mapped. The three loci which we mapped are outG and outH, which are located between polC and dnaA, and outI, which is located near pycA. Using the cloned DNAs and derived plasmids in dot hybridization experiments with RNA extracted from cells at different developmental stages, we defined for two clones a region that is transcribed only during the outgrowth phase.