Characterization of two carotenoid gene promoters in the cyanobacterium Synechocystis sp. PCC 6803

Fernández-González, Blanca; Martínez-Férez, Isabel M.; Vioque, Agustı́n

doi:10.1016/s0167-4781(98)00239-5

Cited by 21 publications

(14 citation statements)

References 32 publications

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“…The expression levels of both crtB and crtP genes in Synechocystis were very low, and quantifying the mRNA level by Northern hybridization was difficult (10). Thus, we used a reverse transcriptase (RT)-mediated PCR technique to analyze the expression of mRNAs levels.…”

Section: Methodsmentioning

confidence: 99%

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Glucose-induced Expression of Carotenoid Biosynthesis Genes in the Dark Is Mediated by Cytosolic pH in the Cyanobacterium Synechocystis sp. PCC 6803

Ryu

Song

Lee

et al. 2004

Journal of Biological Chemistry

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The expression of carotenoid biosynthesis genes coding for phytoene synthase (crtB), phytoene desaturase (crtP), -carotene desaturase (crtQ), and ␤-carotene hydroxylase (crtR) is dependent upon light in the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis). We have demonstrated that the expression of the above four genes was also elevated in the dark-adapted Synechocystis cells upon glucose treatment as a consequence of transcriptional activation. Treatment with glucose analogs such as L-glucose, 3-O-methylglucose, 2-deoxyglucose, and mannose, or inactivation of glucose uptake and phosphorylation by deletion mutation of glucose transporter (glcP) and glucokinase (gk), respectively, did not induce up-regulation of carotenoid genes. When respiratory electron transport or coupling to oxidative phosphorylation was inhibited, glucose induction was not observed, indicating that respiratory electron transport per se is not critical for the expression of these genes. In agreement with this view, the extent of gene expression showed a saturation curve with increasing acridine yellow fluorescence yield, without having a close correlation with the ATP contents or ATP/ADP ratio. The results indicate that glucose induction of carotenoid gene expressions is mediated by an increase in cytosolic pH rather than either redox or glucose sensing.Carotenoids in all photosynthetic organisms including cyanobacteria participate in the light-harvesting process and function in the protection of the photosynthetic apparatus against photo-oxidative damage (1). The cyanobacterium Synechocystis sp. PCC 6803 (hereafter called Synechocystis) contains several genes encoding enzymes involved in carotenoid biosynthesis (2): the crtB gene for phytoene synthase, crtP for phytoene desaturase, crtQ for -carotene desaturase, crtO for ␤-carotene ketolase, and crtR for ␤-carotene hydroxylase.1 Despite an abundance of information about the carotenoid biosynthesis pathway and the genes involved, very little is known about the regulation of the expression of carotenoid biosynthesis genes (3).Light seems to play an important role in the expression of carotenoid biosynthesis genes. In higher plants and green algae, photoreceptors like phytochrome (4, 5) and blue light receptors (6) are involved in light signaling. But, in the cyanobacteria, redox-sensing and signaling by photosynthetic electron transport (7,8) are probably more important than other photosensory systems. This is because the content of carotenoids in Synechococcus sp. PCC 7942 is proportional to the photosynthetic rate (9), and the expression of phytoene synthase (crtB) and phytoene desaturase (crtP) genes in Synechocystis depends upon light intensity (10).To address the redox control over carotenogenesis genes, we took advantage of Synechocystis that grows at the expense of an exogenously supplied sole carbon source, glucose (11). Synechocystis cells uptake external glucose by means of a glucose transporter (glcP, the gene locus sll0771; Ref. 12) and metabolize it further via glycolys...

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Section: Methodsmentioning

confidence: 99%

“…This is because the content of carotenoids in Synechococcus sp. PCC 7942 is proportional to the photosynthetic rate (9), and the expression of phytoene synthase (crtB) and phytoene desaturase (crtP) genes in Synechocystis depends upon light intensity (10).…”

mentioning

confidence: 99%

Glucose-induced Expression of Carotenoid Biosynthesis Genes in the Dark Is Mediated by Cytosolic pH in the Cyanobacterium Synechocystis sp. PCC 6803

Ryu

Song

Lee

et al. 2004

Journal of Biological Chemistry

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“…The fact that the chloroplast outer envelope membrane also contains such carotenoids (28,61) supports the speculation that this plastid envelope is another relic of the endocytic event that led to the development of this organelle (29). It has been suggested that these carotenoids might protect the cyanobacterial cells from high light intensity, particularly in the UV range (92), a hypothesis supported by the facts that the carotenoid synthesis in cyanobacteria is enhanced under these light qualities (32) and that transcription of genes involved in the carotenoid synthesis such as crtB (phytoene synthetase) and crtP (phytoene desaturase) reaches its highest level under these light conditions (34). However, carotenoids are not the only potential photoprotective substances found in cyanobacterial envelopes.…”

Section: Cyanobacterial Cell Walls and Endosymbiosismentioning

confidence: 99%

Cyanobacterial Cell Walls: News from an Unusual Prokaryotic Envelope

2000

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“…PSI promoters with an HL-responsive upstream region are circled. References are shown in parentheses for the following genes: prk and petH (58); glnB (21); recA and lexA (11); ntcA (2); hspA (14); groESL and groEL2 (46); sufBCDS (52); ndhR (17); gap2 (16); desA, desB, desC, and desD (34); secA (35); glnA (49); crhR (47); petF (36); slr0373 (53); psbA2 and psbA3 (39); crtB and crtP (15); icd (44); and hoxE (24). required to clarify the mechanism of HL response dependent on the AT-rich upstream region of PSI genes.…”

Section: Vol 189 2007 High-light-responsive Element Of Photosystem mentioning

confidence: 99%

“…The information on the mechanism of coordinated transcriptional regulation during HL acclimation is quite limited in cyanobacteria. Although HL-responsive cis elements of several genes have been identified (15,16,35,36), there are few pieces of evidence that they work for the coordinated response of multiple genes. The exceptionally well-characterized case are HL-inducible promoters of psbAII and psbAIII (32,33), as well as psbDII (3,10), encoding the reaction center subunits of PSII in Synechococcus sp.…”

Section: Vol 189 2007 High-light-responsive Element Of Photosystem mentioning

confidence: 99%

Coordinated High-Light Response of Genes Encoding Subunits of Photosystem I Is Achieved by AT-Rich Upstream Sequences in the Cyanobacterium Synechocystis sp. Strain PCC 6803

Muramatsu

Hihara

2007

J Bacteriol

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Genes encoding subunits of photosystem I (PSI genes) in the cyanobacterium Synechocystis sp. strain PCC 6803 are actively transcribed under low-light conditions, whereas their transcription is coordinately and rapidly down-regulated upon the shift to high-light conditions. In order to identify the molecular mechanism of the coordinated high-light response, we searched for common light-responsive elements in the promoter region of PSI genes. First, the precise architecture of the psaD promoter was determined and compared with the previously identified structure of the psaAB promoter. One of two promoters of the psaAB genes (P1) and of the psaD gene (P2) possessed an AT-rich light-responsive element located just upstream of the basal promoter region. These sequences enhanced the basal promoter activity under low-light conditions, and their activity was transiently suppressed upon the shift to high-light conditions. Subsequent analysis of psaC, psaE, psaK1, and psaLI promoters revealed that their light response was also achieved by AT-rich sequences located at the ؊70 to ؊46 region. These results clearly show that AT-rich upstream elements are responsible for the coordinated high-light response of PSI genes dispersed throughout Synechocystis genome.Photosynthetic organisms have ability to cope with the changes in light environment by modulating both the structure and the function of the photosynthetic machinery (31, 59). A typical example is the flexible control of the amounts of photosystem (PS) and light-harvesting antenna complexes depending on the availability of light energy (4, 27, 38). Under lightlimiting conditions, the amount of these complexes is maintained at high level, because maximal capture of light energy is required to fulfill the energy demand of cells. Under light-saturating conditions, on the other hand, they are largely downregulated since absorption of excess light energy tends to cause the generation of harmful reactive oxygen species (6).The dynamics of reaction center complexes during the process of high-light (HL) acclimation have been well characterized in cyanobacteria. Amount of PSI is more strictly downregulated than that of PSII upon the exposure to HL (28,40). The analysis of the pmgA mutant deficient in down-regulation of PSI content revealed that the selective repression of PSI is essential for growth under continuous HL conditions (28, 54). Although the primary determinant of PSI content under HL conditions has not been identified, transcriptional regulation is likely to be one of the important factors. The cyanobacterial PSI complex is comprised of about 11 subunits, with some exceptions (23), and genes encoding these subunits (PSI genes) are dispersed throughout the genome. In Synechocystis sp. strain PCC 6803, PSI genes are actively transcribed under low-light (LL) conditions, whereas their transcription is coordinately and rapidly down-regulated upon the shift to HL conditions (26,29,30,42,57), except for the psaK2 gene encoding an HL-inducible isoform of the PsaK subunit (19)...

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Characterization of two carotenoid gene promoters in the cyanobacterium Synechocystis sp. PCC 6803

Cited by 21 publications

References 32 publications

Glucose-induced Expression of Carotenoid Biosynthesis Genes in the Dark Is Mediated by Cytosolic pH in the Cyanobacterium Synechocystis sp. PCC 6803

Glucose-induced Expression of Carotenoid Biosynthesis Genes in the Dark Is Mediated by Cytosolic pH in the Cyanobacterium Synechocystis sp. PCC 6803

Cyanobacterial Cell Walls: News from an Unusual Prokaryotic Envelope

Coordinated High-Light Response of Genes Encoding Subunits of Photosystem I Is Achieved by AT-Rich Upstream Sequences in the Cyanobacterium Synechocystis sp. Strain PCC 6803

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