Activation of the Bacillus subtilis hut operon at the onset of stationary growth phase in nutrient sporulation medium results primarily from the relief of amino acid repression of histidine transport

Atkinson, Mariette R.; Wray, Lewis V.; Fisher, Susan H.

doi:10.1128/jb.175.14.4282-4289.1993

Cited by 13 publications

(11 citation statements)

References 29 publications

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“…The methods used for bacterial cultivation in minimal medium and Difco nutrient sporulation medium (DSM) (37) have been previously described (2,3). Cells grown in DSM medium and minimal medium containing glucose with arginine as the sole nitrogen source were inoculated with overnight cultures grown for four generations in fresh medium before they were used to inoculate the cultures harvested for enzyme assays.…”

Section: Methodsmentioning

confidence: 99%

Expression of the Bacillus subtilis ureABC operon is controlled by multiple regulatory factors including CodY, GlnR, TnrA, and Spo0H

1997

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Microbial ureases are multisubunit metalloenzymes that hydrolyze urea to form carbonic acid and two molecules of ammonia (24). The carbonic acid then dissociates, and the ammonia molecules protonate to form ammonium, causing the pH to increase. Thus, the degradation of urea provides ammonium for incorporation into intracellular metabolites and facilitates survival in acidic environments (7,24). The structural genes encoding both the urease subunits, ureA, ureB, and ureC, and the accessory proteins required for assembly of the urease nickel metallocenter are typically clustered at a single locus (24).

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Section: Methodsmentioning

confidence: 99%

Expression of the Bacillus subtilis ureABC operon is controlled by multiple regulatory factors including CodY, GlnR, TnrA, and Spo0H

1997

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“…Two types of nitrogen-dependent control have been observed in B. subtilis. One was observed in studies of the hut operon, which functions in the utilization of histidine as a nitrogen source (2,3), and in studies of citB (aconitase) (14) and the dciA operon (34,35). In these cases, expression is under amino acid-dependent repression in addition to carbon catabolite repression.…”

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Nitrogen regulation of nasA and the nasB operon, which encode genes required for nitrate assimilation in Bacillus subtilis

et al. 1995

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The divergently transcribed nasA gene and nasB operon are required for nitrate and nitrite assimilation in Bacillus subtilis. The ␤-galactosidase activity of transcriptional lacZ fusions from the nasA and nasB promoters was high when cells were grown in minimal glucose medium containing poor nitrogen sources such as nitrate, proline, or glutamate. The expression was very low when ammonium or glutamine was used as the sole nitrogen source. The repression of the genes during growth on good sources of nitrogen required wild-type glutamine synthetase (GlnA), but not GlnR, the repressor of the glnRA operon. Primer extension analysis showed that the ؊10 region of each promoter resembles those of A -recognized promoters. Between the divergently oriented nasA and nasB promoters is a region of dyad symmetry. Mutational analysis led to the conclusion that this sequence is required in cis for the activation of both nasA and nasB. The derepression of these genes in a glnA mutant also required this sequence. These results suggest that an unidentified transcriptional activator and glutamine synthetase function in the regulation of nasA and the nasB operon.

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“…Secondly, transcription from the hut promoter is negatively regulated in response to amino acid availability at an operator, hutO A , that lies immediately downstream of the hut promoter. The activation of hut expression at the onset of stationary phase in B. subtilis cultures grown in nutrient sporulation medium has been proposed to result from the relief of amino acid repression (3).…”

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Role of CodY in regulation of the Bacillus subtilis hut operon

1996

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Bacillus subtilis mutants deficient in amino acid repression of the histidine utilization (hut) operon were isolated by transposon mutagenesis. Genetic characterization of these mutants indicated that they most likely contained transposon insertions within the codVWXY operon. The codY gene is required for nutritional regulation of the dipeptide permease (dpp) operon. An examination of hut expression in a ⌬codY mutant demonstrated that amino acid repression exerted at the hutO A operator, which lies immediately downstream of the hut promoter, was defective in a ⌬codY mutant. The codY gene product was not required for amino acid regulation of either hut induction or the expression of proline oxidase, the first enzyme in proline degradation. This indicates that more than one mechanism of amino acid repression is present in B. subtilis. An examination of dpp and hut expression in cells during exponential growth in various media revealed that the level of CodY-dependent regulation appeared to be related to the growth rate of the culture.In Bacillus subtilis, L-histidine is degraded to ammonia, glutamate, and formamide by four enzymes, histidase, urocanase, imidazolone propionate aminohydrolase, and formimino-Lglutamate formiminohydrolase (16). These enzymes are encoded by genes that lie within the multicistronic hut operon (4, 13). DNA sequence analysis has revealed that the hut operon contains six open reading frames (19,29). The first structural gene within the hut operon, hutP, encodes a positive regulatory protein (19). The four open reading frames immediately downstream of hutP, hutHUIG, encode the histidine catabolic enzymes (4, 13, 29). The derived amino acid sequence of the final hut gene, hutM, has sequence similarities with bacterial amino acid permeases and has been proposed to encode a histidine permease (29). A factor-independent transcriptional terminator lies between the hutP and hutH genes (19,27).Expression of the B. subtilis hut operon is tightly regulated by histidine induction, carbon catabolite repression, and amino acid repression (2, 4). The DNA sites involved in hut regulation were identified by genetic and deletion analyses. Histidine-dependent induction of the hut operon occurs primarily by transcriptional antitermination at the terminator located between the hutP and hutH genes (27). Carbon catabolite repression of hut expression is exerted at two sites within the hut operon (18, 28). The hutO CR1 site lies immediately downstream of the hut promoter and only weakly regulates hut expression. The hutO CR2 site, which is required for complete hut catabolite repression, is located over 200 bp downstream of the hut transcriptional start site. Amino acid repression blocks two different steps in hut expression (27). First, inhibition of the transport of L-histidine, the hut inducer, in amino acidgrown cultures prevents induction of the hut operon. Secondly, transcription from the hut promoter is negatively regulated in response to amino acid availability at an operator, hutO A , that lies immediat...

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Activation of the Bacillus subtilis hut operon at the onset of stationary growth phase in nutrient sporulation medium results primarily from the relief of amino acid repression of histidine transport

Cited by 13 publications

References 29 publications

Expression of the Bacillus subtilis ureABC operon is controlled by multiple regulatory factors including CodY, GlnR, TnrA, and Spo0H

Expression of the Bacillus subtilis ureABC operon is controlled by multiple regulatory factors including CodY, GlnR, TnrA, and Spo0H

Nitrogen regulation of nasA and the nasB operon, which encode genes required for nitrate assimilation in Bacillus subtilis

Role of CodY in regulation of the Bacillus subtilis hut operon

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