Regulatory factors controlling photosynthetic reaction center and light-harvesting gene expression in Rhodobacter capsulatus

Sganga, Michael W.; Bauer, Carl E.

doi:10.1016/0092-8674(92)90037-d

Cited by 182 publications

(233 citation statements)

References 42 publications

Supporting

Mentioning

216

Contrasting

Order By: Relevance

“…The fact that substantial levels of Crt and Bchl are produced aerobically in PRRB78 indicates that in R. sphaeroides, the accumulation of these pigments and spectral complexes is under the direct control of prrB. In R. capsulatus, using bchC::lacZ and bchH::lacZ translational fusions (34,40), the role of regA and regB on pigment synthesis was not as apparent as observed here for R. sphaeroides.…”

Section: Discussionmentioning

confidence: 50%

“…A similar gene, regA, had previously been identified in the related bacterium Rhodobacter capsulatus, in which it positively regulates the expression of puf::lacZ, puh::lacZ, and puc::lacZ translational fusions. regA was reported not to be involved in regulation of the genes which encode the enzymes involved in the synthesis of the carotenoid (Crt) or Bchl pigments (40). The prrA equivalent from R. sphaeroides NCIB 8253, designated regA, has also been cloned and sequenced (38).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Oxygen-insensitive synthesis of the photosynthetic membranes of Rhodobacter sphaeroides: a mutant histidine kinase

Eraso¹,

Kaplan²

1995

J Bacteriol

121

204

View full text Add to dashboard Cite

Two new loci, prrB and prrC, involved in the positive regulation of photosynthesis gene expression in response to anaerobiosis, have been identified in Rhodobacter sphaeroides. prrB encodes a sensor histidine kinase that is responsive to the removal of oxygen and functions through the response regulator PrrA. Inactivation of prrB results in a substantial reduction of photosynthetic spectral complexes as well as in the inability of cells to grow photosynthetically at low to medium light intensities. Together, prrB and prrA provide the major signal involved in synthesis of the specialized intracytoplasmic membrane (ICM), harboring components essential to the light reactions of photosynthesis. Previously, J. K. Lee and S. Kaplan (J. Bacteriol. 174:1158-1171, 1992) identified a mutant which resulted in high-level expression of the puc operon, encoding the apoproteins giving rise to the B800-850 spectral complex, in the presence of oxygen as well as in the synthesis of the ICM under conditions of high oxygenation. This mutation is shown to reside in prrB, resulting in a leucine-to-proline change at position 78 in mutant PrrB (PRRB78). Measurements of mRNA levels in cells containing the prrB78 mutation support the idea that prrB is a global regulator of photosynthesis gene expression. Two additional mutants, PRRB1 and PRRB2, which make two truncated forms of the PrrB protein, possess substantially reduced amounts of spectral complexes. Although the precise role of prrC remains to be determined, evidence suggests that it too is involved in the regulatory cascade involving prrB and prrA. The genetic organization of the photosynthesis response regulatory (PRR) region is discussed.Rhodobacter sphaeroides is a purple, nonsulfur photoheterotrophic bacterium whose mode of growth depends on the concentration of oxygen in the surrounding environment (49). At high oxygen concentrations, R. sphaeroides grows chemoheterotrophically, and morphologically it resembles a typical gram-negative bacterium (3). Under low oxygen or anaerobiosis, the photosynthetic membrane system, designated the intracytoplasmic membrane (ICM), is induced; the ICM fills the interior of the cell, and its abundance is inversely related to the incident light intensity (25). The ICM contains all of the structural and functional components of the photosynthetic apparatus. Included are three distinct bacteriochlorophyll (Bchl) a pigment-protein complexes: the photochemical reaction center (RC) (36) and the two light-harvesting complexes, designated the B800-850 and B-875 spectral complexes (7, 9). When grown anaerobically in the dark, in the presence of alternative electron acceptors, the gratuitous synthesis of the ICM occurs (53).Lee and Kaplan (28) provided the first demonstration that a relatively simple switching mechanism must be involved in the repression of photosynthesis gene expression by oxygen in the genus Rhodobacter when they isolated the spontaneous mutant T 1a , which accumulates photosynthetic membranes in the presence of high oxygen. Subsequen...

show abstract

Section: Discussionmentioning

confidence: 50%

mentioning

confidence: 99%

Oxygen-insensitive synthesis of the photosynthetic membranes of Rhodobacter sphaeroides: a mutant histidine kinase

Eraso¹,

Kaplan²

1995

J Bacteriol

121

204

View full text Add to dashboard Cite

show abstract

“…Several trans-acting factors have been isolated by the use of this approach (Eraso & Kaplan, 1994;Pollich e t al., 1993;Sganga & Bauer, 1992). Although proven successful, this approach has some obvious limitations, e.g.…”

Section: Discussionmentioning

confidence: 99%

“…The second gene, designated prrB (Eraso & Kaplan, 1995), encodes a cognate histidine-kinase for PrrA. In R. capsulattls an analogous two-component (RegA and RegB) regulatory system has also been described (Inoue et al, 1995 ;Mosley et al, 1994 ;Sganga & Bauer, 1992). PhillipsJones & Hunter (1994) cloned and sequenced a prrA/ regA homologue from yet another strain of R. sphaeroides and showed its ability to partially complement the R. capstllattls regA mutation.…”

Section: Introductionmentioning

confidence: 99%

Isolation of regulatory mutants in photosynthesis gene expression in Rhodobacter sphaeroides 2.4.1 and partial complementation of a PrrB mutant by the HupT histidine-kinase

Gomelsky

Kaplan

1995

Microbiology

View full text Add to dashboard Cite

The photosynthetic bacterium Rhodobacter sphaemides responds to the transition from aerobiosis to anaerobic photosynthesis by increasing the expression of the photosynthesis genes. Mutants have been isolated based on their inability, following such a transition, to increase transcription of the puc operon encoding the apoproteins of the light-harvesting complex II. Mutant D5, a representative of one mutant class, described here, although remaining photosynthetically competent, produced only low levels of the photosynthetic spectral complexes. Complementation analysis revealed that either the gene for the photosynthesis response regulator prrA or the gene encoding its cognate sensor kinase, prrB, was capable of rescuing this mutant. However, partial complementation of this mutant was achieved by placing in trans additional copies of other defined genes from the cosmid library of R. sphaeroides. We describe this effect in detail, attributable to the hupT gene, which has been proposed to encode a histidine-kinase for the hydrogen uptake system in Rhodobacter capsulatus. The effect of HupT on the expression of the photosynthesis genes was mediated through PrrA and independent of a functioning hydrogen uptake system. Thus, we raise the possibility that HupT can participate in phosphorylation of the heterologous response regulator PrrA by so-called cross-talk and therefore partially compensate for the defect in the mutant described. The observation of cross-talk, together with the complementation analysis, allowed us to assign the original mutation to the prrB gene; this was confirmed by DNA sequencing. Analysis of cross-talk in the wild-type, prrB and prrA genetic backgrounds suggested that besides kinase activity, PrrB may possess phosphatase activity toward PrrA. We also report the cloning, organization and structure of some of the hup genes from R. sphaeroides and construction of a Hup-strain.

show abstract

“…Research efforts in this area are now directed towards understanding the mechanism of the control of photosynthesis (PS) gene expression and recently a number of trans-acting factors involved in this process have been identified in R. capszlatzs (Sganga & Bauer, 1992;Buggy et al, 1994;Buggy & Bauer, 1995) and R. sphaeroides (Penfold & Pemberton, 1991Eraso & Kaplan, 1994 Zeilstra-Ryalls & Kaplan, 1995a). Although considerable progress has been made, the mechanism(s) of light and oxygen sensing in Rhodobacter and the means by which these environmental signals are linked to changes in gene expression are not fully understood.…”

Section: M H O R N E J M P E M B E R T O N and A G M C E W mentioning

confidence: 99%

Photosynthesis gene expression in Rhodobacter sphaeroides is regulated by redox changes which are linked to electron transport

1996

View full text Add to dashboard Cite

The effect of the respiratory electron acceptor nitrous oxide on the synthesis of the photosynthetic apparatus of Rhodobacter sphaeroides was examined. In phototrophically grown cells, the addition of nitrous oxide caused a reduction in the level of light-harvesting complex I and light-harvesting complex II under conditions of high light intensity (200 W m-2) and low light intensity (16 W m-2). 5-Aminolaevulinate synthase activity was decreased during growth in the presence of nitrous oxide and this limited production of spectral complexes since addition of exogenous 5-aminolaevulinic acid partially suppressed the effect of nitrous oxide. The effect of nitrous oxide on the expression of the operons encoding the pigment-binding proteins of light-harvesting complex I (puf), light-harvesting complex II (puc) and the two isoenzymes of 5-aminolaevulinate synthase (hemA and hemT) were measured using transcriptional fusions to lacZ. Nitrous oxide caused a decrease in puf and hemA transcription. However, there was an apparent increase in the expression of puc and hemT transcriptional fusions. The level of lightharvesting complexes in cells grown in the dark with different electron acceptors was also examined. Cells grown anaerobically with DMSO had a higher level of light-harvesting complexes than those grown anaerobically with nitrous oxide as electron acceptor. Cells grown aerobically had the lowest level of light-harvesting complexes. It is proposed that FnrL-dependent and FnrL-independent expression of photosynthesis genes is modulated by redox changes elicited by nitrous oxide respiration.Keywords : photosynthesis, gene expression, Rhodobacter sphaeroides, anaerobic respiration INTRODUCTIONMany species of purple non-sulfur phototrophic bacteria exhibit remarkable bioenergetic versatility. These bacteria are able to respire using oxygen as a terminal electron acceptor, while under anaerobic conditions they can catalyse cyclic photosynthetic electron transfer and respiration with a variety of electron acceptors (McEwan, 1994). Since the pioneering experiments of Cohen-Bazire e t a/. (1957) it has been established that oxygen represses the formation of the photosynthetic apparatus while under anaerobic conditions the size of the photosynthetic apparatus is inversely related to the incident light intensity (Aagard & Sistrom, 1972 & Bowen, 1981 ; Wu e t al., 1991) encodes most of the information required for the synthesis of pigment-binding proteins, Bch and carotenoids (Crt). I. M. H O R N E , J. M. P E M B E R T O N and A. G. M c E W A N sphaeroides (PembertonMany of these genes, including the pzrf operon (encoding LH I and RC-L and RC-M polypeptides) (Williams e t al., , 1984 Kiley e t al., 1987) Lee & Kaplan, 1992) and detailed studies of mRNA turnover have been made (reviewed by Klug, 1993). Research efforts in this area are now directed towards understanding the mechanism of the control of photosynthesis (PS) gene expression and recently a number of trans-acting factors involved in this process have been iden...

show abstract

Regulatory factors controlling photosynthetic reaction center and light-harvesting gene expression in Rhodobacter capsulatus

Cited by 182 publications

References 42 publications

Oxygen-insensitive synthesis of the photosynthetic membranes of Rhodobacter sphaeroides: a mutant histidine kinase

Oxygen-insensitive synthesis of the photosynthetic membranes of Rhodobacter sphaeroides: a mutant histidine kinase

Isolation of regulatory mutants in photosynthesis gene expression in Rhodobacter sphaeroides 2.4.1 and partial complementation of a PrrB mutant by the HupT histidine-kinase

Photosynthesis gene expression in Rhodobacter sphaeroides is regulated by redox changes which are linked to electron transport

Contact Info

Product

Resources

About