GENETIC RECOMBINATION IN BACILLUS SUBTILIS

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Genetic transformation in Bacillus subtilis is a process by which DNA is taken up and integrated into a homologous recipient genome, thereby permanently altering the heredity of the cell. Transformation in this organism is dependent on the development of the competent state. Competence is reached during the stationary phase of growth in specific media. Thus, the development of "natural" competence is distinct from competence in Escherichia coli. It involves the synthesis of several proteins and is accompanied by the cessation of DNA replication and the synthesis of stable RNA. This project will characterize the molecular events that occur during the binding, fragmentation, and uptake of donor transforming DNA. The physical state of the recipient genome in the competent cell and during transformation will also be characterized. An existing collection of transposon-induced non- competent mutants will be investigated. The competence genes defined by these mutations will be cloned and sequenced. The products of these genes will be characterized. The regulation of competence gene expression will be investigated, particularly with regard to the level at which regulation takes place, the interactions of competence genes, and the sigma factors required for their expression. The possibility that competent cells produce a soluble, extracellular factor required for the development of competence will be investigated. Additional competence deficient mutants will be isolated and characterized, in an attempt to approach saturation of the competence gene map.