Targeted inactivation of the <i>hrcA</i> repressor gene in cyanobacteria

Nakamoto, Hitoshi; Suzuki, Michiru; Kojima, Kensuke

doi:10.1016/s0014-5793(03)00768-3

Cited by 59 publications

(73 citation statements)

References 31 publications

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“…PCC 6803, while a groEL2 mutant of Thermosynechococcus elongatus is high-temperature sensitive. 14,15) The mutant is also cold sensitive, which is consistent with the fact that the groEL2 gene is uniquely cold-induced. 15) GroEL1 can replace GroEL functionally in E. coli, while GroEL2 cannot.…”

supporting

confidence: 75%

Comparative Biochemical Characterization of Two GroEL Homologs from the CyanobacteriumSynechococcus elongatusPCC 7942

Huq

Sueoka

Narumi

et al. 2010

Bioscience, Biotechnology, and Biochemistry

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supporting

confidence: 75%

Comparative Biochemical Characterization of Two GroEL Homologs from the CyanobacteriumSynechococcus elongatusPCC 7942

Huq

Sueoka

Narumi

et al. 2010

Bioscience, Biotechnology, and Biochemistry

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“…In cyanobacteria, the expression of heat shock genes is regulated at the transcriptional level under heat shock and other stress conditions (Webb et al, 1990;Kanesaki et al, 2002;Nakamoto et al, 2003), and HSPs play important roles in the tolerance of cyanobacterial cells to heat, cold, and oxidative stress (Nakamoto et al, 2001;Nakamoto, 2002, 2003). The genome of Synechocystis includes the sll1670 gene , which encodes an ortholog of HrcA, a negative regulator of the expression of the grpE-dnaK-dnaJ and groESL operons for chaperonins in Bacillus subtilis (Hecker et al, 1986).…”

mentioning

confidence: 99%

The Histidine Kinase Hik34 Is Involved in Thermotolerance by Regulating the Expression of Heat Shock Genes in Synechocystis

et al. 2005

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Histidine kinases (Hiks) in Synechocystis sp. PCC 6803 are involved in the transduction of signals associated with various kinds of environmental stress. To examine the potential role in thermotolerance of Hiks, we used genome microarray analysis to screen a Hik knockout library for mutations that affected the expression of genes for heat shock proteins. Mutation of the hik34 gene enhanced the levels of transcripts of a number of heat shock genes, including htpG and groESL1. Overexpression of the hik34 gene repressed the expression of these heat shock genes. In addition, the cells with a mutant gene for Hik34 (DHik34 cells) survived incubation at 48°C for 3 h, while wild-type cells and cells with mutations in other Hiks were killed. However, mutation of the hik34 gene had only an insignificant effect on the global expression of genes upon incubation of the mutant cells at 44°C for 20 min. Quantitative two-dimensional gel electrophoresis revealed that levels of GroES and HspA were elevated in DHik34 cells after incubation of cells at 42°C for 60 min. We overexpressed recombinant Hik34 protein in Escherichia coli and purified it. We found that the protein was autophosphorylated in vitro at physiological temperatures, but not at elevated temperatures, such as 44°C. These results suggest that Hik34 might negatively regulate the expression of certain heat shock genes that might be related to thermotolerance in Synechocystis.

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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%

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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Targeted inactivation of the hrcA repressor gene in cyanobacteria

Cited by 59 publications

References 31 publications

Comparative Biochemical Characterization of Two GroEL Homologs from the CyanobacteriumSynechococcus elongatusPCC 7942

Comparative Biochemical Characterization of Two GroEL Homologs from the CyanobacteriumSynechococcus elongatusPCC 7942

The Histidine Kinase Hik34 Is Involved in Thermotolerance by Regulating the Expression of Heat Shock Genes in Synechocystis

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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