Transition state regulator AbrB inhibits transcription of Bacillus amyloliquefaciens FZB45 phytase through binding at two distinct sites located within the extended phyC promoter region.
We have previously identified the phyC gene of Bacillus amyloliquefaciens FZB45, encoding extracellular phytase, as a member of the PhoP regulon, which is expressed only during phosphate starvation. Its sigma(A)-dependent promoter is positively and negatively regulated by the phosphorylated PhoP response regulator in a phosphate-dependent manner (O. Makarewicz, S. Dubrac, T. Msadek, and R. Borriss, J. Bacteriol. 188:6953-6965, 2006). Here, we provide experimental evidence that the transcription of phyC underlies a second control mechanism exerted by the global transient-phase regulator protein, AbrB, which hinders its expression during exponential growth. Gel mobility shift and DNase I footprinting experiments demonstrated that AbrB binds to two different regions in the phyC promoter region that are separated by about 200 bp. One binding site is near the divergently orientated yodU gene, and the second site is located downstream of the phyC promoter and extends into the coding region of the phyC gene. Cooperative binding to the two distant binding regions is necessary for the AbrB-directed repression of phyC transcription. AbrB does not affect the transcription of the neighboring yodU gene.
Makarewicz
Oliwia
O
Institut für Biologie, Humboldt Universität Berlin, Chausseestrasse 117, D-10115 Berlin, Germany.
Neubauer
Svetlana
S
Preusse
Corinna
C
Borriss
Rainer
R
D010832:6-Phytase / Q000235:genetics*; D001407:Bacillus / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D016172:DNA Fingerprinting; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D010832:6-Phytase