[Activation of protein biosynthesis in outgrowing spores of Bacillus subtilis]

The programme of protein synthesis as an indicator for the control of gene expression was examined during outgrowth of Bacillus subtilis spores. At various stages of outgrowth cells of Bacillus subtilis were labelled with 35S-L-methionine. Extracted proteins were separated on two-dimensional gels according to O'Farrell (1975). Three groups of proteins were synthesized during outgrowth: 1. During all stages of outgrowth a great number of "vegetative genes" is expressed. The programme of protein synthesis of the outgrowing cell is very similar to that of a vegetative cell. 2. Only a few proteins--probably the products of outgrowth-genes--are synthesized especially in outgrowing spores and turned off at different stages of outgrowth. 3. The synthesis of a minor group of vegetative proteins is triggered during different stages of outgrowth. In contrast to earlier assumptions (comp. Torriani and Levinthal 1967, Hansen et al. 1970, Galizzi et al. 1976) we suggest that only a small portion of the genome is activated during outgrowth as a dependent sequence. These results are discussed on the basis of earlier concepts about the regulation of outgrowth as a developmentally regulated gene expression programme.