Bacillus subtilis NhaC, an Na+/H+ antiporter, influences expression of thephoPR operon and production of alkaline phosphatases

Citation
Z. Pragai et al., Bacillus subtilis NhaC, an Na+/H+ antiporter, influences expression of thephoPR operon and production of alkaline phosphatases, J BACT, 183(8), 2001, pp. 2505-2515
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
JOURNAL OF BACTERIOLOGY
ISSN journal
0021-9193 → ACNP
Volume
183
Issue
8
Year of publication
2001
Pages
2505 - 2515
Database
ISI
SICI code
0021-9193(200104)183:8<2505:BSNANA>2.0.ZU;2-G
Abstract
When Bacillus subtilis is subjected to phosphate starvation, genes of the P ho regulon are either induced or repressed. Among those induced are genes e ncoding alkaline phosphatases (APases). A set of isogenic mutants, with a b eta -galactosidase gene transcriptionally fused to the inactivated target g ene, was used to identify genes that influence the operation of the Pho reg ulon. One such gene was nhaC (previously yheL). In the absence of NhaC, gro wth and APase production were enhanced, while the production of other non-P ho-regulon secretory proteins (proteases and alpha -amylase) did not change . The influence of NhaC on growth, APase synthesis, and its own expression was dependent on the external Na+ concentration. Other monovalent cations s uch as Li+ or K+ had no effect. We propose a role for NhaC in the uptake of Na+. nhaC appears to be encoded by a monocistronic operon and, contrary to previous reports, is not in the same transcriptional unit as yheK, the gen e immediately upstream. The increase in APase production was dependent on a n active PhoR, the sensor kinase of the two-component system primarily resp onsible for controlling the Pho regulon. Transcriptional fusions showed tha t the phoPR operon and both phoA (encoding APaseA) and phoB (encoding APase B) were hyperinduced in the absence of NhaC and repressed when this protein was overproduced. This suggests that NhaC effects APase production via pho PR.