srfA is an operon required for surfactin production, competence development, and efficient sporulation in Bacillus subtilis

Abstract

The srfA locus of BaciUlus subtilis is defined by a transposon Tn917 insertion and is required for productpon of the peptide secondary metabolite surfactin. The srfA locus was isolated by cloning the DNA flanking srfA::Tn917 insertions followed by chromosome walking. The cloned region is an operon of oyer 25 kb which covers the transcription initiation region but not the intact 3' end of srfA. csh-293, which was previously identified as a Tn9171ac mutation that impairs competence development and causes a condifoWl defect in sporulation, was known to be located in the vicinity of the srfA locus within the B. subtlis genome. The csh-293::Tn9171ac mutation was discovered to cause a defect in surfactin production and was shown to be located in the srfA operon by its cotransformation with srfA mutations and' by Southern hybridization analysis. Insertion mutations in srfA, created by the chromosomal integration of plasmids bearing overlapping srfA DNA fragments, were ex for their effects on surfactin production, competence, and sporulation. AB three processes were found to require the intact 5' half of the srfA operon, whereas the 3' half of srfA was found to be required for sporulation and surfactin production but not competence. These experiments show that srfA gene products function in B. subtilis cell specialization and differentiation.

Mutational Analysis of the sbo-alb Locus of Bacillus subtilis : Identification of Genes Required for Subtilosin Production and Immunity

“…In this case, a cat gene cassette was inserted into the BssHII sites residing within the albB gene and the resulting construct was introduced by double recombination into the sbo-alb operon. We had observed pre-viously that the cat gene, if oriented in the same direction as the transcription of the operon into which it is inserted, directs transcription through the genes downstream of the insertion (21).…”

Private link between signal and response in Bacillus subtilis quorum sensing

“…The ComX-dependent QS response (measured as srfA expression) is induced at the beginning of the stationary phase (20,21). We investigated the dynamics of srfA expression in the QS proficient (QS + ) B. subtilis BD4720 (srfAyfp) and QS signal-deficient (QSS − ) B. subtilis BD4729 (srfA-cfp) strains.…”

Convergent sensing pathways mediate response to two extracellular competence factors in Bacillus subtilis.

“…2A; Magnuson et al 1994). Full expression of srfA (also known as csh293, coraL) requires the spoOH gene product (Jaacks et al 1989;van Sinderen et al 1990;Nakano et al 1991a), a (r factor (cr H) of RNA polymerase that is required for the initiation of sporulation. Mutations in spoOH cause a defect in the development of competence (Sadaie and Kada 1983;Albano et al 1987), at least in part because of a decrease in expression of srfA (Jaacks et al 1989;Hahn and Dubnau 1991).…”