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1 Department of Plant and Environmental Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
2 Bioscience Center, Nagoya University, Nagoya, Japan
3 Department of Biochemistry and Molecular Biology, Saitama University, Saitama, Japan
4 National Institute for Basic Biology, Okazaki, Japan
Correspondence
Aaron Kaplan
aaronka{at}vms.huji.ac.il
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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hik31, and the glucose-sensitive strain of Synechocystis, do not possess glucokinase activity, although a transcript originating from glk, encoding glucokinase, is present. Inactivation of glk led to severe sensitivity to glucose, indicating that the presence of glucose itself, within the cells, inflicted this sensitivity. On the other hand, sensitivity to 2-deoxy-D-glucose was lower in glk, thus distinguishing between the effect of glucose itself and that of its analogue, which, in the absence of glucokinase activity, may not be phosphorylated. Addition of glucose led to a small rise in glucose-6-phosphate dehydrogenase activity in the wild type, but constitutive activity was observed in the hik31 mutant regardless of the presence of glucose. Microarray analyses showed only small changes in the abundance of global transcripts in Synechocystis following glucose addition, but the transcription levels of several genes, including icfG, but not glk, were strongly affected by inactivation of hik31. The mechanism(s) whereby Hik31 is involved in glucose sensing and response is discussed.
These authors contributed equally to this study.
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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; Stal & Moezelaar, 1997). Despite its importance to our understanding of cell metabolism, little is known about the mechanism(s) whereby cyanobacteria respond to the presence of glucose in their environment. Furthermore, while D-glucose-sensitive (gs) and D-glucose-tolerant (GT) strains of Synechocystis sp. PCC 6803 (henceforth referred to as Synechocystis) are available, the mechanisms distinguishing their response to glucose are poorly understood.
Zhang et al. (1998) introduced glcP, which encodes the glucose transporter in Synechocystis, into the chromosome of the obligate autotroph Synechococcus sp. strain PCC 7942 (henceforth referred to as Synechococcus). This resulted in glucose sensitivity in the Synechococcus cells that expressed glcP; a glucose-tolerant subclone was found to have lost glcP. Integration of glcP in a replicative vector allowed glucose transport and photoheterotrophic growth of Synechococcus, but this could not be maintained. These data suggested that lack of glucose transport could partly explain obligate autotrophy, at least in Synechococcus, and that glucose uptake was essential to lead to glucose sensitivity by a mechanism that was unknown at that time.
Exposure of Synechocystis to glucose results in many changes at various cellular levels, including carbon metabolism (Knowles & Plaxton, 2003), pigmentation (Hsiao et al., 2004; Ryu et al., 2004), phosphorylation patterns (Bloye et al., 1992), carbon dioxide uptake (Kaplan & Reinhold, 1999) and redox state of the plastoquinone pool (S. Kahlon, I. Ohad & A. Kaplan, unpublished results). The mechanisms whereby Synechocystis senses glucose are not known. The transmembrane proteins Snf3, Rgt2 (Moriya & Johnston, 2004) and Gpr1 (Lemaire et al., 2004) have been implicated in glucose sensing in the yeast Saccharomyces cerevisiae. Our analysis showed that the N-terminal of Snf3p is highly homologous to glcP from Synechocystis, but also that the cyanobacterium lacks the other half (the sensor?) of Snf3p. Synechocystis does not possess a homologue of Rgt2 or the G-protein Gpr1. In plants, glucose sensing is mediated by hexokinase (Moore et al., 2003), but Synechocystis does not possess hexokinase, and phosphorylation of glucose is catalysed by glucokinase. Interestingly, despite the numerous responses of Synechocystis to the presence of glucose, and with the exception of cases such as carotene biosynthesis in the dark (Ryu et al., 2004), the profiles of transcript abundance and protein levels during steady-state growth have not shown marked differences between control and glucose-supplied GT cells (Knowles & Plaxton, 2003; Tu et al., 2004; Yang et al., 2002). This may suggest that the response to glucose in Synechocystis rests mainly on alterations at the level of post-translational modifications, or modulation of enzyme activities.
Synechocystis mutants impaired in their growth in the presence of glucose have been isolated. A icfG mutant cannot grow in the presence of glucose under low carbon dioxide conditions (Beuf et al., 1994). The icfG (slr1860) gene, encoding a protein phosphatase, is part of a gene cluster that encodes a protein kinase, a protein phosphatase and two phosphoproteins (Shi et al., 1999). A reduced level of gap1 transcript (encoding glyceraldehyde-3-phosphate dehydrogenase, GAPDH) in a hik8 mutant of Synechocystis lowers the ability of the cells to degrade glucose, and grow in the dark (Singh & Sherman, 2005), thus implicating this sensor kinase in the response to glucose. PmgA, which shows homology with anti-sigma factor, is essential for the acclimation of Synechocystis to changing light intensity (Hihara et al., 1998). Growth of a pmgA mutant is impaired when glucose is provided in the light (Hihara & Ikeuchi, 1997), but the mechanism(s) involved is not known.
It is widely accepted that the oxidative pentose pathway is the main route of carbohydrate breakdown in cyanobacteria (Hagen & Meeks, 2001). However, inactivation of zwf encoding glucose-6-phosphate dehydrogenase (G6PD) in Synechococcus has little effect on the rate of oxygen uptake in the dark (Scanlan et al., 1995), thus suggesting that alternative metabolic routes are present. The level of glucose-6-phosphate (G6P) increases following initiation of photosynthesis, whereas that of 6-phosphogluconate declines (Pelroy & Bassham, 1972), suggesting regulation of G6PD. Indeed, detailed kinetic studies have shown strict regulation of G6PD activity by G6P, ATP, NADP and NADPH, and a shift in the nature of the curve relating the rate of G6PD activity to G6P concentration, from hyperbolic to sigmoidal, with a rising pH (Grossman & McGowan, 1975). Biochemical analyses have indicated that G6PD is present in various aggregation states that show variable kinetic properties (Gleason, 1996; Schaeffer & Stanier, 1978; Sundaram et al., 1998). It has been suggested that OpcA is involved in the assembly of G6PD, and its oligomerization and activation, in various cyanobacteria (Min & Golden, 2000; Sundaram et al., 1998). In contrast, detailed studies on G6PD from Nostoc punctiforme do not support involvement of OpcA in its aggregation, but show that the presence of OpcA strongly affects the activity of G6PD, and its affinity towards its substrate G6P (Hagen & Meeks, 2001).
The seminal studies by Shestakov and colleagues (Koksharova et al., 1998) have shown the importance of gap1 and gap2, which are closely related to the genes encoding cytosolic and chloroplast GAPDH, respectively, of higher plants. A mutant impaired in gap1 is unable to grow on glucose, but retains autotrophic growth in carbon dioxide. On the other hand, the gap2 mutant can perform photomixotrophic growth on glucose, but loses the ability to grow under photosynthetic conditions. Biochemical analyses indicate that Gap2 operates in the reductive photosynthetic (Calvin) cycle, and in non-photosynthetic gluconeogenesis, whereas Gap1 is essential for glycolytic glucose breakdown only (where the catabolic activity of Gap2 is repressed by a low-molecular-weight inhibitor of an unknown nature).
We show that inactivation of sll0790 and its plasmid homologue slr6041 (encoding sensory histidine kinase, Hik31) in the GT strain of Synechocystis results in a mutant unable to grow in the presence of glucose. These findings implicate Hik31 in the mechanisms that regulate between photoautotrophic and photomixotrophic growth.
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METHODS |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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glcP mutant was obtained by ligating the PCR products from positions 18 to 542 (from the ATG codon), and 631 to 1133, with a chloramphenicol-resistance-encoding cassette, thereby deleting nt 543–630. The glk mutant was obtained by ligating the PCR products from positions 75 to 625, and 809 to 1327, with a cassette encoding kanamycin resistance, thereby deleting nt 626–808. The double mutants glk/hik31 and glcP/hik31 were also prepared during the course of this study using the same constructs. All the mutants used here were fully segregated; we could not detect WT uninterrupted fragments in their DNA.
The hik31 gene is located immediately downstream of sll0788 and sll0789 (http://www.kazusa.or.jp/cyano/Synechocystis). A sll0788 mutant was insensitive to glucose (not shown). We could not specifically inactivate sll0789 encoding a putative two-component response regulator of the OmpR subfamily, which is likely to interact with Hik31 (Sato et al., 2004), without affecting the transcription of hik31. Thus, at this time we cannot unequivocally conclude whether the GS phenotype observed in the sll0789 mutant was due to inactivation of hik31, or an effect on the abundance of its response regulator Sll0789.
The cells were grown in BG11 medium (Stanier et al., 1971) at 30 °C, with continuous illumination of 60 µmol photons m–2 s–1; the medium was supplemented with 20 mM HEPES/NaOH, pH 7·8, and, where appropriate, the relevant antibiotics. Liquid cultures were bubbled with air enriched with 1–3 % carbon dioxide (high CO2), or a mixture of 1 : 1 air and carbon-dioxide-free air (low CO2); agar plates were placed in a plexiglas chamber aerated with one of these gas mixtures.
Western analysis and RT-PCR.
Cultures were grown to a cell density of OD750 0·5, transferred to fresh BG11 medium, either with or without 5 mM glucose, and harvested when required. For Western analyses, the cells were lysed mechanically, and the extracts placed onto polyacrylamide gels (7 %) in the presence (denaturing) or absence (native) of SDS. The sampling, but not the running buffer, contained 1·25 % 
-mercaptoethanol. The proteins were transferred to nitrocellulose membranes, and probed with antibodies raised against G6PD and OpcA (kindly provided by Dr N. Mann, University of Warwick, UK, and Dr J. Meeks, University of California, Davis, CA, USA, respectively). Detection was with an ECL Western blot kit (catalogue no. RPN2106; Amersham). Analyses of transcript abundances encoding G6PD, Gap1, Gap2, GidA, PmgA, IcfG and 16S rRNA were performed using RT-PCR on RNA isolated from the GT strain of Synechocystis and mutant hik31. When required, the cells were exposed to 5 mM D-glucose for various time periods before RNA extraction; the cells were lysed, and total RNA was prepared as described by Katoh et al. (2001). A 100 ng quantity of total RNA was used in the reverse transcriptase reaction, using Super script II (catalogue no. 18064-014; Invitrogen) to synthesize cDNA, followed by PCR amplification using appropriate primers for 12–25 cycles, depending on the abundance of the transcript. Twelve to fourteen cycles were sufficient in the case of 16S rDNA, whereas 25 cycles were required in the case of gidA. The specific primers used are shown in Table 1.
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Microarray analyses.
Isolation of RNA, and the analyses, were performed as described by Hihara et al. (2004).
Oxygen exchange.
A Clark-type oxygen electrode (Kaplan et al., 1980) and a membrane inlet mass spectrometer (Helman et al., 2003) were used to measure the rate of oxygen uptake or evolution. Cell suspensions were placed in the measuring chamber at 30 °C, and provided with D-glucose as required.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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Addition of D-glucose to mutant hik31 (in which both genes are inactivated) arrested its growth within about 20 h (Fig. 1a, b). In the absence of glucose, the GT and GS strains of Synechocystis, and all the mutants raised on the background of GT during the course of this study, including hik31, grew equally well under the conditions used here in either solid (Fig. 1c) or liquid BG11 media (not shown). Addition of L-glucose or 3-o-methyl-D-glucose did not inhibit the growth of the WT or the hik31 mutant (Fig. 1b). On the other hand, addition of either 2-deoxy-D-glucose (2-D-Glc), which can undergo phosphorylation, or fructose was lethal for the GT and hik31 strains (Fig. 1b, c). Raising the level of Pi in the BG11 medium by 10-fold did not alter the response of the WT and the hik31 mutant to glucose or 2-D-Glc (Fig. 1b), suggesting that the response to 2-D-Glc was not due to a low internal Pi level, which could be caused by phosphorylation, but rather that the response was due to lack of further metabolism of this substrate.
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hik31 mutant was sensitive to internal or external glucose, we inactivated glcP encoding the glucose transporter. Mutants glcP and glcP/hik31 grew like the WT in the presence or absence of glucose, in the light (Fig. 1c
), indicating that glucose must enter the cells to induce sensitivity. As expected, mutants in which glcP was inactivated could not grow in the dark on glucose (not shown), and were not sensitive to the presence of 5 mM 2-D-Glc or fructose, unlike the WT (Fig. 1c; Flores & Schmetterer, 1986). These data also suggest that fructose enters the cells via the glucose transporter.
Glucokinase activity
The results presented in Fig. 1 suggest that phosphorylation of glucose or its analogues inside the cells could lead to the glucose sensitivity observed in this study. In Synechocystis, conversion of glucose to G6P is mediated by glucokinase, which is encoded by glk. Mutants glk and glk/hik31 could not grow in the presence of glucose (Fig. 1c), indicating that the entry of glucose itself into the cells inhibited growth. This observation raises the possibility that sensitivity of the GS strain and the hik31 mutant to glucose is due to impaired glucokinase activity. Measurements of enzyme activity on cell extracts (Table 2) confirmed that the GS and hik31 strains did not possess glucokinase activity. We were confronted with a very large variability in glucokinase activities in various cell extracts from the WT, despite the fact that, to the best of our knowledge, the growth and experimental conditions were identical. In addition, the methodology used to break the cells was identical for the measurements of G6PD (see below) and glucokinase activities, and we repeatedly examined these two activities on the same extracts; nevertheless, the reproducibility of the results obtained was much better for G6PD than glucokinase. Furthermore, the data in Table 2 are provided per milligram of protein in the cell extract, and thus breaking efficiency is normalized. Nevertheless, it was clear that glucokinase activity was essentially zero in all the experiments where extracts from GS or hik31 strains were examined.
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icfG and pmgA strains that possess glucokinase activity (not shown). On the other hand, mutants hik31 and glk, lacking glucokinase activity, could not grow on glucose in the dark. Interestingly, inactivation of glk partly alleviated the sensitivity of the WT and hik31 mutant to 2-D-Glc (Fig. 1c), suggesting that phosphorylation by glucokinase is involved in the toxicity of 2-D-Glc.
G6PD
The G6P produced by glucokinase activity is further metabolized by G6PD. The activity of G6PD increased slightly in WT cells that were provided with glucose, but it was significantly higher in the hik31 mutant, irrespective of the presence of glucose (Fig. 2). To examine a possible effect of inactivation of hik31 on the profile of G6PD, we extracted proteins from the WT and the mutant before and after addition of glucose, and separated them on a native (not shown) and a denaturating gel (Fig. 3). In agreement with the elevated G6PD activity in cell extracts from the hik31 strain, the levels of G6PD and of OpcA were also higher in the mutant than in the WT (Fig. 3). In both strains, the levels of OpcA and of G6PD were not affected by the presence of glucose (Fig. 3). Interestingly, a 105 kDa polypeptide was observed in protein extracts from the WT loaded onto the denaturing gel, but this was not observed in extracts from the hik31 mutant. The nature of this polypeptide is not known, but, since it was recognized by the G6PD antibody, we cannot discount the possibility that it is a dimer of G6PD that is resistant to the denaturing SDS conditions.
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hik31 mutant, with or without exposure to 5 mM D-glucose for 6 h. In general, our results confirmed earlier reports (see Introduction) that the profiles of transcript abundance do not show large changes in response to the addition of glucose; two exceptions are the rpl and rps genes involved in ribosome biosynthesis, which were upregulated two- to fourfold by glucose. In Table 3, we provide the ratio (in the hik31 mutant versus that in the WT) of transcript abundances of genes that encode proteins directly involved in glucose metabolism, and that were also examined by RT-PCR and Northern analyses, during the course of this study. The analyses showed that the levels of the transcripts originating from glk (encoding glucokinase), glcP (encoding the glucose transporter), opcA (slr1734) and zwf (slr1843, encoding G6PD) hardly differed between the WT and the hik31 mutant (Table 3), and that the levels were not significantly affected by the addition of glucose (not shown). Among the transcripts examined by RT-PCR, that of icfG increased significantly after addition of D-glucose to the WT, but it was missing, or at least not detected, in RNA from the hik31 mutant (Fig. 4). The abundance of transcripts originating from gap1, gidA and pmgA was slightly affected by the addition of glucose, but the effect was much smaller than that observed for icfG (not shown).
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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). Since inactivation of glcP, encoding the glucose transporter, alleviated the sensitivity of the hik31 mutant to glucose (Fig. 1), we conclude that entry of glucose into the cells is required to induce glucose sensitivity. The hik31 and GS strains of Synechocystis lack glucokinase activity (Table 2), and inactivation of glk (encoding glucokinase) in the GT strain resulted in sensitivity to glucose (Fig. 1c). These data suggest that glucose sensitivity is due to an inability to metabolize the compound. An ability of the GT strain to consume glucose is indicated, for instance, by a large rise in the rate of oxygen uptake (respiration) following the addition of glucose in the dark (Ohkawa et al., 2000). This was not the case in the hik31 and glk strains, where the presence of glucose hardly affected the rate of oxygen uptake (not shown). Taken together, the data indicate that the presence of glucose itself, within the cells of strains unable to metabolize it, induces their sensitivity.
Since the abundance of a transcript originating from glk was not affected by inactivation of hik31 (Table 3), we propose that downregulation of glucokinase activity in this strain is probably mediated by post-transcriptional regulation, the nature of which is being examined. In addition to glk, the genome of Synechocystis contains another ORF, slr0329, annotated as encoding glucokinase (http://www.kazusa.or.jp/cyano/Synechocystis). However, glk and slr0329 are not homologous, and, unlike the glk mutant, inactivation of slr0329 did not result in sensitivity to glucose (not shown). Thus the role, function and annotation of slr0329 remain to be elucidated.
Sensitivity to non-metabolized glucose analogues that can undergo phosphorylation (Fig. 1) has been observed in many organisms, including yeast (Rincon et al., 2001) and plants (Kulma et al., 2004). The ability to phosphorylate glucose is essential for the induction of cell death in nutrient-limited yeast (Granot & Dal, 1997). In contrast, we observed sensitivity to D-glucose in Synechocystis strains lacking glucokinase activity (GS, hik31 and glk), where the presence of D-glucose within the cells appeared to be lethal, but the mechanism involved is unknown. The Synechocystis genome contains genes homologous to gidA (sll0202 and sll0204) and gidB (slr0072); the name gid (glucose-inhibited division) is derived from the observation that deletion of the gene in Escherichia coli results in a cell-elongation phenotype when glucose is provided (von Meyenburg et al., 1982). gidA is widely distributed, and highly conserved, among prokaryotes and plants (including Arabidopsis thaliana and rice). Recent analyses of the structures of GidA (Iwasaki et al., 2004) and GidB (Romanowski et al., 2002), and characterization of mutants in various organisms in which gidA is inactivated (Kinscherf & Willis, 2002; Sha et al., 2004), suggest that the latter is involved in the coordination of replication, and that it can act as a global regulator and moderator of translation. It is not known whether the gid genes function similarly in Synechocystis, and whether they are involved in its sensitivity to internal glucose. It should be noted that supply of glucose had little effect on the abundance of transcripts for gidA and gidB in Synechocystis, and that the number of these transcripts was very low (not shown).
Involvement of regulatory genes, including hik8 and icfG, in the response of Synechocystis to glucose has been reported by others (Beuf et al., 1994; Singh & Sherman, 2005). Unlike the hik31 mutant, a hik8 mutant can grow in the presence of glucose, but not in the dark, or an extended dark period, presumably due to an altered ability to express gap1, and thus to an altered ability to utilize glycogen in the dark (Singh & Sherman, 2005). In contrast, the hik31 mutant was found to possess a normal level of gap1 transcript (not shown), but was unable to grow in the dark due to lack of glucokinase activity. It has been reported that inactivation of icfG, encoding a protein serine phosphatase in Synechocystis (Shi et al., 1999), results in the inability to grow under limiting levels of inorganic carbon in the presence of glucose (Beuf et al., 1994). In contrast, glucose sensitivity of the hik31 mutant was observed in cells exposed to either high or low levels of carbon dioxide, although the mutant was less sensitive to the presence of glucose under low CO2 (not shown). The icfG mutant was able to grow in the presence of glucose in the dark, whereas the hik31 mutant could not. A considerable rise in the level of icfG transcript was induced by glucose in the WT, but this transcript was not detected in the hik31 mutant, regardless of the presence of glucose (Fig. 4). These data suggest that, in addition to activation of glucokinase, Hik31 is essential for the expression of icfG.
It is known that G6PD is present in various levels of aggregation (Gleason, 1996; Schaeffer & Stanier, 1978; Sundaram et al., 1998), but the biological significance of the aggregation states is not known. The constitutive higher level and activity of G6PD exhibited by the hik31 mutant (Figs 2 and 3), and higher degree of aggregation (observed in native gels, not shown), suggest that Hik31 is also involved in the modulation of G6PD. The data also suggest that cells of the hik31 mutant are in an ‘acclimated phase’ to glucose, regardless of its presence. This may indicate a dual role for Hik31 as a repressor of some of the glucose-related functions, and as an inducer/activator of others, including the presence of the 105 kDa polypeptide, and the expression of icfG.
As indicated in the Introduction, the supply of glucose to Synechocystis cells imposes many changes in various and seemingly unrelated processes and activities. It is therefore surprising that analysis of global gene expression by means of DNA microarray (performed here, and by others; Singh & Sherman, 2005; Tu et al., 2004) did not show marked changes in the transcript abundance of many genes. Nevertheless, detailed Northern, RT-PCR and biochemical analyses suggested changes in the expression of several genes, and the activity of certain enzymes, including glucokinase and G6PD, in response to deletion of hik31 (Table 2; Figs 2, 3 and 4). A detailed proteomic approach, using some of the mutants raised here, is required to identify other components involved in the complex network whereby the cells regulate between photoautotrophic and photomixotrophic modes of growth.
Finally, while the data presented here support the suggestion that Hik31 plays an important role in the response of Synechocystis cells to glucose, the mechanisms involved, and the interactions with other components, are yet to be elucidated. Here, it is worth mentioning a serious difficulty that we faced during the course of this study – the stability of the phenotypes of some of the mutants used. It was apparent that addition of glucose caused an immense selection pressure, which led to the appearance of many suppression mutants. Analysis of these mutants may help to identify additional components in this complex system, and the interaction between them.
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ACKNOWLEDGEMENTS |
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REFERENCES |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
Bloye, S. A., Silman, N. J., Mann, N. H. & Carr, N. G. (1992). Bicarbonate concentration by Synechocystis PCC 6803 modulation of protein phosphorylation and inorganic carbon transport by glucose. Plant Physiol 99, 601–606.
Flores, E. & Schmetterer, G. (1986). Interaction of fructose with the glucose permease of the cyanobacterium Synechocystis sp. strain PCC 6803. J Bacteriol 166, 693–696.
Gleason, F. K. (1996). Glucose-6-phosphate dehydrogenase from the cyanobacterium, Anabaena sp. PCC 7120: purification and kinetics of redox modulation. Arch Biochem Biophys 334, 277–283.[CrossRef][Medline]
Granot, D. & Dal, N. (1997). Sugar induced cell death in yeast is dependent on the rate of sugar phosphorylation as determined by Arabidopsis thaliana hexokinase. Cell Death Differ 4, 555–559.[CrossRef][Medline]
Grossman, A. & McGowan, R. E. (1975). Regulation of glucose-6-phosphate dehydrogenase in blue-green algae. Plant Physiol 55, 658–662.
Hagen, K. D. & Meeks, J. C. (2001). The unique cyanobacterial protein OpcA is an allosteric effector of glucose-6-phosphate dehydrogenase in Nostoc punctiforme ATCC 29133. J Biol Chem 276, 11477–11486.
Helman, Y., Tchernov, D., Reinhold, L., Shibata, M., Ogawa, T., Schwarz, R., Ohad, I. & Kaplan, A. (2003). Genes encoding A-type flavoproteins are essential for photoreduction of O2 in cyanobacteria. Curr Biol 13, 230–235.[CrossRef][Medline]
Hihara, Y. & Ikeuchi, M. (1997). Mutation in a novel gene required for photomixotrophic growth leads to enhanced photoautotrophic growth of Synechocystis sp. PCC 6803. Photosynth Res 53, 243–252.[CrossRef]
Hihara, Y., Sonoike, K. & Ikeuchi, M. (1998). A novel gene, pmgA, specifically regulates photosystem stoichiometry in the cyanobacterium Synechocystis sp. PCC 6803 in response to high light. Plant Physiol 117, 1206–1216.
Hihara, Y., Muramatsu, M., Nakamura, K. & Sonoike, K. (2004). A cyanobacterial gene encoding an ortholog of Pirin is induced under stress conditions. FEBS Lett 574, 101–105.[CrossRef][Medline]
Hsiao, H. Y., He, Q. F., van Waasbergen, L. G. & Grossman, A. R. (2004). Control of photosynthetic and high-light-responsive genes by the histidine kinase DspA: negative and positive regulation and interactions between signal transduction pathways. J Bacteriol 186, 3882–3888.
Iwasaki, W., Miyatake, H., Ebihara, A. & Miki, K. (2004). Crystallization and preliminary X-ray crystallographic studies of the small form of glucose-inhibited division protein A from Thermus thermophilus HB8. Acta Cryst D60, 515–517.[CrossRef]
Kaplan, A. & Reinhold, L. (1999). The CO2 concentrating mechanisms in photosynthetic microorganisms. Annu Rev Plant Physiol Plant Mol Biol 50, 539–570.[CrossRef]
Kaplan, A., Badger, M. R. & Berry, J. A. (1980). Photosynthesis and intracellular inorganic carbon pool in the blue-green algae Anabaena variabilis: response to external CO2 concentration. Planta 149, 219–226.[CrossRef]
Katoh, H., Hagino, N., Grossman, A. R. & Ogawa, T. (2001). Genes essential to iron transport in the cyanobacterium Synechocystis sp. strain PCC 6803. J Bacteriol 183, 2779–2784.
Kinscherf, T. G. & Willis, D. K. (2002). Global regulation by gidA in Pseudomonas syringae. J Bacteriol 184, 2281–2286.
Knowles, V. L. & Plaxton, W. C. (2003). From genome to enzyme: analysis of key glycolytic and oxidative pentose-phosphate pathway enzymes in the cyanobacterium Synechocystis sp. PCC 6803. Plant Cell Physiol 44, 758–763.
Koksharova, O., Schubert, M., Shestakov, S. & Cerff, R. (1998). Genetic and biochemical evidence for distinct key functions of two highly divergent GAPDH genes in catabolic and anabolic carbon flow of the cyanobacterium Synechocystis sp. PCC 6803. Plant Mol Biol 36, 183–194.[CrossRef][Medline]
Kulma, A., Villadsen, D., Campbell, D. G., Meek, S. E. M. E., Harthill, J., Nielsen, T. H. & MacKintosh, C. (2004). Phosphorylation and 14-3-3 binding of Arabidopsis 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. Plant J 37, 654–667.[CrossRef][Medline]
Lemaire, K., Van de Velde, S., Van Dijck, P. & Thevelein, J. M. (2004). Glucose and sucrose act as agonist and mannose as antagonist ligands of the G protein-coupled receptor Gpr1 in the yeast Saccharomyces cerevisiae. Mol Cell 16, 293–299.[CrossRef][Medline]
Min, H. T. & Golden, S. S. (2000). A new circadian class 2 gene, opcA, whose product is important for reductant production at night in Synechococcus elongatus PCC 7942. J Bacteriol 182, 6214–6221.
Moore, B. L. Z., Rolland, F., Hall, Q., Cheng, W. H., Liu, Y. X., Hwang, I., Jones, T. & Sheen, J. (2003). Role of the Arabidopsis glucose sensor HXK1 in nutrient, light, and hormonal signaling. Science 300, 332–336.
Moriya, H. & Johnston, M. (2004). Glucose sensing and signaling in Saccharomyces cerevisiae through the Rgt2 glucose sensor and casein kinase I. Proc Natl Acad Sci U S A 101, 1572–1577.
Ohkawa, H., Pakrasi, H. B. & Ogawa, T. (2000). Two types of functional NAD(P)H dehdrogenase in Synechocystis sp. strain PCC 6803. J Biol Chem 275, 31630–31634.
Pelroy, R. A. & Bassham, J. A. (1972). Photosynthetic and dark carbon metabolism in unicellular blue-green algae. Arch Mikrobiol 86, 303–322.
Rincon, A. M., Codon, A. C., Castrejon, F. & Benitez, T. (2001). Improved properties of baker's yeast mutants resistant to 2-deoxy-D-glucose. Appl Environ Microbiol 67, 4279–4285.
Rippka, R., Deruelles, J., Waterbury, J.-B., Herdman, M. & Stanier, R.-Y. (1979). Genetic assignments, strain histories and properties of pure cultures of cyanobacteria. J Gen Microbiol 111, 1–61.
Romanowski, M. J., Bonanno, J. B. & Burley, S. K. (2002). Crystal structure of the Escherichia coli glucose-inhibited division protein B (GidB) reveals a methyltransferase fold. Proteins 47, 563–567.[CrossRef][Medline]
Ryu, J. Y., Song, J. Y., Lee, J. M., Jeong, S. W., Chow, W. S., Choi, S. B., Pogson, B. J. & Park, Y. I. (2004). Glucose-induced expression of carotenoid biosynthesis genes in the dark is mediated by cytosolic pH in the cyanobacterium Synechocystis sp PCC 6803. J Biol Chem 279, 25320–25325.
Sato, S., Nakamura, Y. & Tabata, S. (2004). A large scale analysis of protein–protein interactions in Synechocystis sp. PCC 6803. Plant Cell Physiol 45, S37–S37.
Scanlan, D. J., Sundaram, S., Newman, J., Mann, N. H. & Carr, N. G. (1995). Characterization of a zwf mutant of Synechococcus sp. strain PCC 7942. J Bacteriol 177, 2550–2553.
Schaeffer, F. & Stanier, R. Y. (1978). Glucose-6-phosphate dehydrogenase of Anabaena sp. Arch Microbiol 116, 9–19.[CrossRef][Medline]
Sha, J., Kozlova, E. V., Fadl, A. A., Olano, J. P., Houston, C. W., Peterson, J. W. & Chopra, A. K. (2004). Molecular characterization of a glucose-inhibited division gene, gidA, that regulates cytotoxic enterotoxin of Aeromonas hydrophila. Infect Immun 72, 1084–1095.
Shi, L., Bischoff, K. M. & Kennelly, P. J. (1999). The icfG gene cluster of Synechocystis sp. strain PCC 6803 encodes an Rsb/Spo-like protein kinase, protein phosphatase, and two phosphoproteins. J Bacteriol 181, 4761–4767.
Singh, A. K. & Sherman, L. A. (2005). Pleiotropic effect of a histidine kinase on carbohydrate metabolism in Synechocystis sp. strain PCC 6803 and its requirement for heterotrophic growth. J Bacteriol 187, 2368–2376.
Stal, L. J. & Moezelaar, R. (1997). Fermentation in cyanobacteria. FEMS Microbiol Rev 21, 179–211.
Stanier, R. Y., Kunisawa, R., Mandel, M. & Cohen-Bazire, G. (1971). Purification and properties of unicellular blue-green algae (order Chroococcales). Bacteriol Rev 3, 171–205.
Sundaram, S., Karakaya, H., Scanlan, D. J. & Mann, N. H. (1998). Multiple oligomeric forms of glucose-6-phosphate dehydrogenase in cyanobacteria and the role of OpcA in the assembly process. Microbiology 144, 1549–1556.
Tu, C.-J., Shrager, J., Burnap, R. L., Postier, B. L. & Grossman, A. R. (2004). Consequences of a deletion in dspA on transcript accumulation in Synechocystis sp. strain PCC 6803. J Bacteriol 186, 3889–3902.
von Meyenburg, K., Jorgensen, B. B., Nielsen, J. & Hansen, F. G. (1982). Promoters of the atp operon coding for the membrane-bound ATP synthase of Escherichia coli mapped by Tn10 insertion mutations. Mol Gen Genet 188, 240–248.[CrossRef][Medline]
Yang, C., Hua, Q. & Shimizu, K. (2002). Integration of the information from gene expression and metabolic fluxes for the analysis of the regulatory mechanisms in Synechocystis. Appl Microbiol Biotechnol 58, 813–822.[CrossRef][Medline]
Zhang, C. C., Jeanjean, R. & Joset, F. (1998). Obligate phototrophy in cyanobacteria: more than a lack of sugar transport. FEMS Microbiol Lett 161, 285–292.[CrossRef][Medline]
Received 11 September 2005;
revised 14 November 2005;
accepted 15 November 2005.
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) and mutant 
) grown in liquid BG11 medium supplemented with 5 mM D-glucose. After 24 h growth, the cells were diluted, and the growth experiment was continued under otherwise identical conditions. Light intensity was 50 µmol photons m–2 s–1, and the temperature was 30 °C. (b, c) The WT, and mutants 
