Proteus mirabilis urease: transcriptional regulation by UreR

Abstract

Proteus mirabilis urease catalyzes the hydrolysis of urea, initiating the formation of urinary stones. The enzyme is critical for kidney colonization and the development of acute pyelonephritis. Urease is induced by urea and is not controlled by the nitrogen regulatory system (ntr) or catabolite repression. Purified whole-cell RNA from induced and uninduced cultures of P. mirabilis and Escherichia coli harboring cloned urease sequences was probed with a 4.2-kb BglI fragment from within the urease operon. Autoradiographs of slot blots demonstrated 4.2- and 5.8-fold increases, respectively, in urease-specific RNA upon induction with urea. Structural and accessory genes necessary for urease activity, ureD, A, B, C, E, and F, were previously cloned and sequenced (B. D. Jones and H. L. T. Mobley, J. Bacteriol. 171:6414-6422, 1989). A 1.2-kb EcoRV-BamHI restriction fragment upstream of these sequences confers inducibility upon the operon in trans. Nucleotide sequencing of this fragment revealed a single open reading frame of 882 nucleotides, designated ureR, which is transcribed in the direction opposite that of the urease structural and accessory genes and encodes a 293-amino-acid polypeptide predicted to be 33,415 Da in size. Autoradiographs of sodium dodecyl sulfate-polyacrylamide gels of [35S]methionine-labeled polypeptides obtained by in vitro transcription-translation of the PCR fragments carrying only ureR yielded a single band with an apparent molecular size of 32 kDa. Fragments carrying an in-frame deletion within ureR synthesized a truncated product. The predicted UreR amino acid sequence contains a potential helix-turn-helix motif and an associated AraC family signature and is similar to that predicted for a number of DNA-binding proteins, including E. coli proteins that regulate acid phosphatase synthesis (AppY), porin synthesis (EnvY), and rhamnose utilization (RhaR). These data suggest that UreR governs the inducibility of P. mirabilis urease.

Detection of Urer and Urec Among Proteus Mirabilis

“…Furthermore, Mobley and Chippendale (1990) showed that all P. mirabilis isolated from different clinical source produced a high amount of urease phenotypically compared to other bacteria and there was a concordance between phenotypic and molecular detection of urease activity. In addition, Nicholson et al [28] and Ali and Yousif (2015) found that ureC gene is very abundant in P. mirabilis bacteria.…”

Single-step purification of Proteus mirabilis urease accessory protein UreE, a protein with a naturally occurring histidine tail, by nickel chelate affinity chromatography

“…The urease gene cluster of P. mirabilis contains eight genes, including the urea-dependent transcriptional activator ureR, the enzyme structural genes ureABC, and the four accessory genes ureDEFG (16,28,32). Mutations in structural or accessory genes usually result in a complete loss of catalytic activity.…”

“…Urease genes of P. mirabilis have been cloned (15) and sequenced (16,28,32), and deletion mutations have been constructed (10,32). In the course of these studies, we observed that clones lacking ureE, ureF, or ureG (accessory genes in the P. mirabilis urease gene cluster) do not express catalytically active urease in unsupplemented medium.…”

Proteus mirabilis interkingdom swarming signals attract blow flies

“…Ammonia is produced by almost all organisms, it is one of the most characteristic odors in fresh manure (Richardson, 1916), and it can attract L. sericata adults (Hilker and Meiners, 2002). Urease catalyzes the hydrolysis of urea into carbon dioxide and ammonia (Nicholson et al, 1993), and in P. mirabilis, urease is encoded by the ure operon that contains eight genes. UreR is the transcription regulator of P. mirabilis urease.…”