The Bacillus subtilis NatK-NatR two-component system regulates expression of the natAB operon encoding an ABC transporter for sodium ion extrusion.
A previous microarray analysis suggested that multicopy yccH, encoding a function-unknown response regulator, enhances expression of natAB, which encodes a two-gene ATP-binding cassette transporter involved in the extrusion of sodium ions. The two-component regulatory system YccG-YccH was therefore renamed NatK-NatR. Here, this observation was confirmed by a lacZ fusion analysis using a strain carrying natA-lacZ. Further, in both natK and natR mutants, natA-lacZ expression was completely abolished, indicating that the NatK-NatR system positively regulates the expression of natAB. In a gel retardation analysis, NatR bound to the natA promoter region. Using purified His-tagged NatR, DNase I footprinting analysis of the natA promoter region suggested that a direct repeat of [TTCA(G)CGACA], separated by a 12 bp space, would be recognized by NatR. Deleted and mutagenized promoter regions of natA were analysed using a lacZ fusion, and it was confirmed that the direct repeat is critical for natA activation by NatR.
Ogura
Mitsuo
M
Institute of Oceanic Research and Development, Tokai University, 3-20-1 Orido-Shimizu, Shizuoka 424-8610, Japan.
Tsukahara
Kensuke
K
Institute of Oceanic Research and Development, Tokai University, 3-20-1 Orido-Shimizu, Shizuoka 424-8610, Japan.
Hayashi
Kentaro
K
Institute of Oceanic Research and Development, Tokai University, 3-20-1 Orido-Shimizu, Shizuoka 424-8610, Japan.
Tanaka
Teruo
T
Institute of Oceanic Research and Development, Tokai University, 3-20-1 Orido-Shimizu, Shizuoka 424-8610, Japan.
D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis* / Q000235:genetics; D000222:Adaptation, Physiological / Q000235:genetics; D019677:Artificial Gene Fusion; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018983:DNA Footprinting; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D009876:Operon; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017384:Sequence Deletion; D012964:Sodium / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D001616:beta-Galactosidase / Q000032:analysis / Q000235:genetics
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D012964:Sodium; D001616:beta-Galactosidase