Use of temperature sensitive mutants to study gene expression during sporulation in Bacillus subtilis

Abstract

Two temperature sensitive sporulation mutants have been characterized. One mutant, which is blocked at stage II, has a short temperature sensitive period that occurs at about the time when the spore septum is formed. Cells can escape th sporulation block, if incubated for a short period at the permissive temperature, but are prevented from doing so by inhibitors of transcription and translation; this suggests that the product of the defective gene is a protein and that the messenger ribonucleic acid which codes for this protein is short lived. The other mutant is blocked at stage IV to V and has a long temperature sensitive period that starts during stage III and precedes the stage at which the mutational defect is phenotypically expressed. The behavior of this mutant in temperature shift experiments suggests that synthesis of the product of the defective gene commences long before it assumes its physiological function.