Two-dimensional polyacrylamide gel electrophoresis of proteins synthesized during early germination of Bacillus subtilis 168 in the presence of actinomycin D.

Two-dimensional gel electrophoresis was used to demonstrate the synthesis of approximately 65 [35S]-methionine-labelled soluble proteins between 0 and 10 min after the start of germination, of approximately 210 proteins at 10-20 min, and of approximately 260 proteins during vegetative growth of Bacillus subtilis. When actinomycin D and [35S]-methionine were administered at the onset of germination and the proteins synthesized during the subsequent 15 min were analyzed, two proteins were detected, and were designated protein I and protein II. Immunoblot analysis with an antiserum raised against RNA polymerase from Escherichia coli demonstrated that protein II corresponded to the sigma A factor of Bacillus subtilis. Thus, the sigma A factor is synthesized during early germination of Bacillus subtilis in the presence of actinomycin D.