CONSTRUCTION OF GUSA TRANSCRIPTIONAL FUSION VECTORS FOR BACILLUS-SUBTILIS AND THEIR UTILIZATION FOR STUDIES OF SPORE FORMATION

A series of gusA transcriptional fusion vectors is described for Bacil lus subtilis (Bs). The series includes a vector for use with the amyE system of Shimotsu and Henner [Gene 43 (1986) 85-94], an integrative v ector and vectors that provide gusA or gusA neo cassettes. The gusA fu sions are compatible with lacZ fusion vectors that are widely used wit h Bs, and gusA and lacZ fusions are expressed at similar levels, beta- Glucuronidase (beta Glu) and beta-galactosidase (beta Gal) do not exhi bit any cross-reactivity, there is very little endogenous beta Glu act ivity in Bs, and there is no indication of mutation to high-level expr ession. We have used strains containing both gusA and lacZ fusions to compare the times of expression of different genes during sporulation.