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Dhakal D, Chen M, Luesch H, Ding Y. Heterologous production of cyanobacterial compounds. J Ind Microbiol Biotechnol 2021; 48:6119914. [PMID: 33928376 PMCID: PMC8210676 DOI: 10.1093/jimb/kuab003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/17/2020] [Indexed: 12/29/2022]
Abstract
Cyanobacteria produce a plethora of compounds with unique chemical structures and diverse biological activities. Importantly, the increasing availability of cyanobacterial genome sequences and the rapid development of bioinformatics tools have unraveled the tremendous potential of cyanobacteria in producing new natural products. However, the discovery of these compounds based on cyanobacterial genomes has progressed slowly as the majority of their corresponding biosynthetic gene clusters (BGCs) are silent. In addition, cyanobacterial strains are often slow-growing, difficult for genetic engineering, or cannot be cultivated yet, limiting the use of host genetic engineering approaches for discovery. On the other hand, genetically tractable hosts such as Escherichia coli, Actinobacteria, and yeast have been developed for the heterologous expression of cyanobacterial BGCs. More recently, there have been increased interests in developing model cyanobacterial strains as heterologous production platforms. Herein, we present recent advances in the heterologous production of cyanobacterial compounds in both cyanobacterial and noncyanobacterial hosts. Emerging strategies for BGC assembly, host engineering, and optimization of BGC expression are included for fostering the broader applications of synthetic biology tools in the discovery of new cyanobacterial natural products.
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Affiliation(s)
- Dipesh Dhakal
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, University of Florida, Gainesville, FL 31610, USA
| | - Manyun Chen
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, University of Florida, Gainesville, FL 31610, USA
| | - Hendrik Luesch
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, University of Florida, Gainesville, FL 31610, USA
| | - Yousong Ding
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, University of Florida, Gainesville, FL 31610, USA
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2
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Cyanobacterial sigma factors: Current and future applications for biotechnological advances. Biotechnol Adv 2020; 40:107517. [DOI: 10.1016/j.biotechadv.2020.107517] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/07/2020] [Accepted: 01/09/2020] [Indexed: 11/15/2022]
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Flores E, Picossi S, Valladares A, Herrero A. Transcriptional regulation of development in heterocyst-forming cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:673-684. [DOI: 10.1016/j.bbagrm.2018.04.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 01/02/2023]
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Gordon GC, Pfleger BF. Regulatory Tools for Controlling Gene Expression in Cyanobacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1080:281-315. [PMID: 30091100 PMCID: PMC6662922 DOI: 10.1007/978-981-13-0854-3_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cyanobacteria are attractive hosts for converting carbon dioxide and sunlight into desirable chemical products. To engineer these organisms and manipulate their metabolic pathways, the biotechnology community has developed genetic tools to control gene expression. Many native cyanobacterial promoters and related sequence elements have been used to regulate genes of interest, and heterologous tools that use non-native small molecules to induce gene expression have been demonstrated. Overall, IPTG-based induction systems seem to be leaky and initially demonstrate small dynamic ranges in cyanobacteria. Consequently, a variety of other induction systems have been optimized to enable tighter control of gene expression. Tools require significant optimization because they function quite differently in cyanobacteria when compared to analogous use in model heterotrophs. We hypothesize that these differences are due to fundamental differences in physiology between organisms. This review is not intended to summarize all known products made in cyanobacteria nor the performance (titer, rate, yield) of individual strains, but instead will focus on the genetic tools and the inherent aspects of cellular physiology that influence gene expression in cyanobacteria.
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Affiliation(s)
- Gina C Gordon
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA.
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA.
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Muro-Pastor AM, Brenes-Álvarez M, Vioque A. A combinatorial strategy of alternative promoter use during differentiation of a heterocystous cyanobacterium. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:449-458. [PMID: 28585763 DOI: 10.1111/1758-2229.12555] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/24/2017] [Accepted: 05/29/2017] [Indexed: 06/07/2023]
Abstract
Heterocystous cyanobacteria such as Nostoc sp. are filamentous photosynthetic organisms that, in response to nitrogen deficiency, undergo a differentiation process transforming certain, semi-regularly spaced cells into heterocysts, devoted to nitrogen fixation. During transition to a nitrogen-fixing regime, growth of most vegetative cells in the filament is temporarily arrested due to nutritional deprivation, but developing heterocysts require intense transcriptional activity. Therefore, the coexistence of arrested vegetative cells and actively developing prospective heterocysts relies on the simultaneous operation of somewhat opposite transcriptional programs. We have identified genes with multiple nitrogen-responsive transcriptional starts appearing in seemingly paradoxical combinations. For instance, sigA, encoding the RNA polymerase housekeeping sigma factor, is transcribed from one major nitrogen stress-repressed promoter and from a second, nitrogen stress-induced promoter. Here, we show that both promoters are expressed with complementary temporal dynamics. Using a gfp reporter we also show that transcription from the inducible promoter takes place exclusively in differentiating heterocysts and is already detected before any morphological or fluorescence signature of differentiation is observed. Tandem promoters with opposite dynamics could operate a compensatory mechanism in which repression of transcription from the major promoter operative in vegetative cells is offset by transcription from a new promoter only in developing heterocyst.
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Affiliation(s)
- Alicia M Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Sevilla, E-41092, Spain
| | - Manuel Brenes-Álvarez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Sevilla, E-41092, Spain
| | - Agustín Vioque
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Sevilla, E-41092, Spain
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Abstract
Group 1 and group 2 sigma factors are sigma factors of bacterial RNA polymerase responsible for transcription from consensus-type promoters. Thus, these sigma factors form the framework for basic transcriptional regulation in bacteria. Cyanobacteria are known to have various group 2 sigma factors, typically more than 4, but only recently the particular function of each sigma factor is being elucidated. In response to environmental signals such as nutrients, light and temperature, cyanobacteria change their transcriptional profile first by activating specific transcription factors and subsequently by modifying the basic transcriptional machinery, which is often involved in the regulation of group 2 sigma factors. In this article, we give an overview of the composition and evolution of group 2 sigma factors in cyanobacteria and summarize what was presently revealed regarding their function.
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Affiliation(s)
- Takashi Osanai
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, 113-0032 Tokyo, Japan
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Davis AK, Palenik B. Characterization of a modular, cell-surface protein and identification of a new gene family in the diatom Thalassiosira pseudonana. Protist 2007; 159:195-207. [PMID: 18162437 DOI: 10.1016/j.protis.2007.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Accepted: 09/29/2007] [Indexed: 11/17/2022]
Abstract
We report the characterization of a cell-surface protein isolated from copper-stressed cells of the centric diatom Thalassiosira pseudonana Hasle and Heimdal (CCMP 1335). This protein has an apparent molecular weight of 100kDa and is highly acidic. The 100kDa protein (p100) sequence is comprised almost entirely of a novel domain termed TpRCR for T. pseudonana repetitive cysteine-rich domain, that is repeated 8 times and that contains conserved aromatic, acidic, and potential metal-binding amino acids. The analysis of the T. pseudonana genome suggests that p100 belongs to a large family of modular proteins that consist of a variable number of TpRCR domain repeats. Based on cell surface biotinylation and antibody data, p100 appears to migrate more rapidly with SDS-PAGE when extracted from cells exposed to high levels of copper; however, the discovery of a large family of TpRCR domain-containing proteins leaves open the possibility that the antibody may be cross-reacting with members of this protein family that are responding differently to copper. The response of the gene encoding p100 at the mRNA level during synchronized progression through the normal cell cycle is similar to previously characterized genes in T. pseudonana encoding cell wall proteins called silaffins.
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Affiliation(s)
- Aubrey K Davis
- Scripps Institution of Oceanography, University of California-San Diego, La Jolla, CA 92093-0202, USA
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Yoshimura H, Okamoto S, Tsumuraya Y, Ohmori M. Group 3 sigma factor gene, sigJ, a key regulator of desiccation tolerance, regulates the synthesis of extracellular polysaccharide in cyanobacterium Anabaena sp. strain PCC 7120. DNA Res 2007; 14:13-24. [PMID: 17376888 PMCID: PMC2779892 DOI: 10.1093/dnares/dsm003] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The changes in the expression of sigma factor genes during dehydration in terrestrial Nostoc HK-01 and aquatic Anabaena PCC 7120 were determined. The expression of the sigJ gene in terrestrial Nostoc HK-01, which is homologous to sigJ (alr0277) in aquatic Anabaena PCC 7120, was significantly induced in the mid-stage of dehydration. We constructed a higher-expressing transformant of the sigJ gene (HE0277) in Anabaena PCC 7120, and the transformant acquired desiccation tolerance. The results of Anabaena oligonucleotide microarray experiments showed that a comparatively large number of genes relating to polysaccharide biosynthesis were upregulated in the HE0277 cells. The extracellular polysaccharide released into the culture medium of the HE0277 cells was as much as 3.2-fold more than that released by the control cells. This strongly suggests that the group 3 sigma factor gene sigJ is fundamental and conducive to desiccation tolerance in these cyanobacteria.
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Affiliation(s)
- Hidehisa Yoshimura
- Center of Systems Biology and Ecology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
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Inoue-Sakamoto K, Gruber TM, Christensen SK, Arima H, Sakamoto T, Bryant DA. Group 3 sigma factors in the marine cyanobacterium Synechococcus sp. strain PCC 7002 are required for growth at low temperature. J GEN APPL MICROBIOL 2007; 53:89-104. [PMID: 17575449 DOI: 10.2323/jgam.53.89] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Three genes, sigF, sigG and sigH, encoding group 3 sigma factors have been cloned and characterized in the marine cyanobacterium Synechococcus sp. strain PCC 7002. The sigF gene product was similar to sigma factors involved in general stress response and sporulation in other organisms, and the sigG and sigH gene products were similar to extracytoplasmic function (ECF) sigma factors. The sigG and sigH genes were associated with the putative regulatory genes and the sizes of transcripts for sigG and sigH genes were large enough to be cotranscribed with the associated downstream genes. The sigG downstream gene was designated sapG (sigG-associated protein), and yeast two-hybrid analysis demonstrated that SigG and SapG interact when produced in yeast cells. Null mutants of these three group 3 sigma factor genes were created by interposon mutagenesis. The growth of the sigF mutant strain was much slower than the wild-type strain at 15 degrees C, although the growth rates at 22 degrees C and 38 degrees C were identical to those of the wild-type strain. The sigG mutant could not grow continuously at 22 degrees C, and no growth occurred at 15 degrees C. Since SigG and SapG interact in yeast cells and the sigG and sapG mutants showed a similar growth phenotype, SapG is likely to be a regulatory protein for SigG involved in the same pathway in transcriptional regulation in this cyanobacterium.
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Affiliation(s)
- Kaori Inoue-Sakamoto
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, University Park, PA 16802, USA.
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Bohne AV, Irihimovitch V, Weihe A, Stern DB. Chlamydomonas reinhardtii encodes a single sigma70-like factor which likely functions in chloroplast transcription. Curr Genet 2006; 49:333-40. [PMID: 16453112 DOI: 10.1007/s00294-006-0060-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 01/13/2006] [Accepted: 01/17/2006] [Indexed: 11/30/2022]
Abstract
Chlamydomonas reinhardtii EST clones encoding a protein highly similar to prokaryotic sigma factors and plant sigma-like factors (SLFs) were used to isolate a BAC clone containing the full-length gene CrRpoD. The gene is likely to be single-copy, in contrast to small gene families encoding SLFs in plants. The CrRpoD mRNA comprises 3,033 nt with an open reading frame of 2,256 nt, encoding a putative protein of 752 amino acids with a molecular mass of 80.2 kDa. The sequence contains conserved regions 2-4 typically found in sigma factors, and an unusually long amino terminal extension, which by in silico analysis has properties of a chloroplast transit peptide. Expression of CrRpoD was confirmed by immunodetection of a 85 kDa polypeptide in a preparation enriched for chloroplast proteins. To demonstrate functionality in transcription initiation, a recombinant CrRpoD-thioredoxin fusion protein was reconstituted with E. coli RNA polymerase core enzyme and tested in vitro. This chimeric holoenzyme specifically bound the spinach psbA and Chlamydomonas rrn16 promoters in gel mobility shift assays and exhibited specific transcription initiation from the same two promoters, providing evidence for the role of CrRpoD as a functional transcription factor.
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Affiliation(s)
- Alexandra-V Bohne
- Institut für Biologie, Humboldt-Universität, Chausseestr. 117, 10115, Berlin, Germany
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Pils D, Wilken C, Valladares A, Flores E, Schmetterer G. Respiratory terminal oxidases in the facultative chemoheterotrophic and dinitrogen fixing cyanobacterium Anabaena variabilis strain ATCC 29413: characterization of the cox2 locus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2004; 1659:32-45. [PMID: 15511525 DOI: 10.1016/j.bbabio.2004.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Revised: 06/14/2004] [Accepted: 06/15/2004] [Indexed: 10/26/2022]
Abstract
Upon nitrogen step-down, some filamentous cyanobacteria differentiate heterocysts, cells specialized for dinitrogen fixation, a highly oxygen sensitive process. Aerobic respiration is one of the mechanisms responsible for a microaerobic environment in heterocysts and respiratory terminal oxidases are the key enzymes of the respiratory chains. We used Anabaena variabilis strain ATCC 29413, because it is one of the few heterocyst-forming facultatively chemoheterotrophic cyanobacteria amenable to genetic manipulation. Using PCR with degenerate primers, we found four gene loci for respiratory terminal oxidases, three of which code for putative cytochrome c oxidases and one whose genes are homologous to cytochrome bd-type quinol oxidases. One cytochrome c oxidase, Cox2, was the only enzyme whose expression, tested by RT-PCR, was evidently up-regulated in diazotrophy, and therefore cloned, sequenced, and characterized. Up-regulation of Cox2 was corroborated by Northern and primer extension analyses. Strains were constructed lacking Cox1 (a previously characterized cytochrome c oxidase), Cox2, or both, which all grew diazotrophically. In vitro cytochrome c oxidase and respiratory activities were determined in all strains, allowing for the first time to estimate the relative contributions to total respiration of the different respiratory electron transport branches under different external conditions. Especially adding fructose to the growth medium led to a dramatic enhancement of in vitro cytochrome c oxidation and in vivo respiratory activity without significantly influencing gene expression.
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Affiliation(s)
- Dietmar Pils
- Institut für Physikalische Chemie, Universität Wien, UZA2, Althanstrasse 14, A-1090 Vienna, Austria.
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Valladares A, Muro-Pastor AM, Herrero A, Flores E. The NtcA-dependent P1 promoter is utilized for glnA expression in N2-fixing heterocysts of Anabaena sp. strain PCC 7120. J Bacteriol 2004; 186:7337-43. [PMID: 15489445 PMCID: PMC523192 DOI: 10.1128/jb.186.21.7337-7343.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expression of the glnA gene encoding glutamine synthetase, a key enzyme in nitrogen metabolism, is subject to a variety of regulatory mechanisms in different organisms. In the filamentous, N(2)-fixing cyanobacterium Anabaena sp. strain PCC 7120, glnA is expressed from multiple promoters that generate several transcripts whose abundance is influenced by NtcA, the transcription factor exerting global nitrogen control in cyanobacteria. Whereas RNA(I) originates from a canonical NtcA-dependent promoter (P(1)) and RNA(II) originates from a sigma(70)-type promoter (P(2)), RNA(IV) is influenced by NtcA but the corresponding promoter (P(3)) does not have the structure of NtcA-activated promoters. Using RNA isolated from Anabaena filaments grown under different nitrogen regimens, we observed, in addition to these transcripts, RNA(V), which has previously been detected only in in vitro transcription assays and should originate from P(4). However, in heterocysts, which are differentiated cells specialized in N(2) fixation, RNA(I) was the almost exclusive glnA transcript. Analysis of P(glnA)::lacZ fusions containing different fragments of the glnA upstream region confirmed that fragments carrying P(1), P(2), or P(3) and P(4) have the ability to promote transcription. Mutation of the NtcA-binding site in P(1) eliminated P(1)-directed transcription and allowed increased use of P(2). The NtcA-binding site in the P(1) promoter and binding of NtcA to this site appear to be key factors in determining glnA gene expression in vegetative cells and heterocysts.
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Affiliation(s)
- Ana Valladares
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Avda. Américo Vespucio s/n, E-41092 Seville, Spain
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13
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Abstract
Many filamentous nitrogen-fixing cyanobacteria protect nitrogenase from oxygen in differentiated cells called heterocysts. Heterocyst development is controlled by the availability of nitrogen compounds in the environment and by intrinsic factors that regulate the frequency and pattern of heterocysts along vegetative cell filaments. Recent progress in understanding heterocyst development in these simple multicellular organisms includes demonstrating the role of 2-oxoglutarate in regulating the activity of the transcription factor NtcA, the identification of additional genes in the regulatory network, such as hetF, and the further characterization of previously identified genes and proteins, including DevR/HepK, hetR, hetN, patS and patB.
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Affiliation(s)
- James W Golden
- Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA.
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Imamura S, Yoshihara S, Nakano S, Shiozaki N, Yamada A, Tanaka K, Takahashi H, Asayama M, Shirai M. Purification, characterization, and gene expression of all sigma factors of RNA polymerase in a cyanobacterium. J Mol Biol 2003; 325:857-72. [PMID: 12527296 DOI: 10.1016/s0022-2836(02)01242-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The expression of RNA polymerase (RNAP) sigma factor genes and proteins was characterized as a first step toward understanding their functions in a unicellular cyanobacterium Synechocystis sp. PCC 6803, which can perform photosynthesis. All nine sigma factors (group 1, SigA; group 2, SigB to SigE; and group 3, SigF to SigI) and each RNAP core subunit (RpoA, RpoB, RpoC1 and RpoC2) were overproduced and purified from Escherichia coli cells, then polyclonal antibodies were prepared. Western blot and primer extension analyses revealed that the intracellular levels of group 1 and 2 sigma factors ranged from 0.9 fmol to 9.3 fmol per microgram of the total protein under conditions of steady-state growth, and that growth phase-dependent or constitutive transcripts were observed. Interestingly, no group 3 sigma factor proteins were detected under normal physiological conditions whereas their transcripts were robust, implying a possible regulation of translational attenuation and/or protein instability. Phylogenetic analysis also revealed that group 3 sigma factor homologues of cyanobacteria are conserved with evolutionary or functionary divergence among them. In vitro and in vivo results indicated significant evidence of high-light responsive SigD expression and its promoter recognition of the photosynthesis gene, psbA. On the other hand, autoregulated sigB transcription, a dramatically increased SigB expression upon the exposure of cells to heat-shock, and specific promoter recognition by SigB with redundancy of other sigma factors on the heat-shock hspA promoter were observed. These findings clearly indicated that SigB is a heat-shock responsive sigma factor. The unique promoter architecture and expression of the relevant sigma factor gene are also discussed herein.
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Affiliation(s)
- Sousuke Imamura
- Laboratory of Molecular Genetics, College of Agriculture, Ibaraki University, Ami, Inashiki, 300-0393, Ibaraki, Japan
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Koksharova OA, Wolk CP. Novel DNA-binding proteins in the cyanobacterium Anabaena sp. strain PCC 7120. J Bacteriol 2002; 184:3931-40. [PMID: 12081965 PMCID: PMC135189 DOI: 10.1128/jb.184.14.3931-3940.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
As an approach towards elucidation of the biochemical regulation of the progression of heterocyst differentiation in Anabaena sp. strain PCC 7120, we have identified proteins that bind to a 150-bp sequence upstream from hepC, a gene that plays a role in the synthesis of heterocyst envelope polysaccharide. Such proteins were purified in four steps from extracts of vegetative cells of Anabaena sp. Two of these proteins (Abp1 and Abp2) are encoded by neighboring genes in the Anabaena sp. chromosome. The genes that encode the third (Abp3) and fourth (Abp4) proteins are situated at two other loci in that chromosome. Insertional mutagenesis of abp2 and abp3 blocked expression of hepC and hepA and prevented heterocyst maturation and aerobic fixation of N(2).
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Affiliation(s)
- Olga A Koksharova
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing 48824, USA
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Meeks JC, Elhai J. Regulation of cellular differentiation in filamentous cyanobacteria in free-living and plant-associated symbiotic growth states. Microbiol Mol Biol Rev 2002; 66:94-121; table of contents. [PMID: 11875129 PMCID: PMC120779 DOI: 10.1128/mmbr.66.1.94-121.2002] [Citation(s) in RCA: 313] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Certain filamentous nitrogen-fixing cyanobacteria generate signals that direct their own multicellular development. They also respond to signals from plants that initiate or modulate differentiation, leading to the establishment of a symbiotic association. An objective of this review is to describe the mechanisms by which free-living cyanobacteria regulate their development and then to consider how plants may exploit cyanobacterial physiology to achieve stable symbioses. Cyanobacteria that are capable of forming plant symbioses can differentiate into motile filaments called hormogonia and into specialized nitrogen-fixing cells called heterocysts. Plant signals exert both positive and negative regulatory control on hormogonium differentiation. Heterocyst differentiation is a highly regulated process, resulting in a regularly spaced pattern of heterocysts in the filament. The evidence is most consistent with the pattern arising in two stages. First, nitrogen limitation triggers a nonrandomly spaced cluster of cells (perhaps at a critical stage of their cell cycle) to initiate differentiation. Interactions between an inhibitory peptide exported by the differentiating cells and an activator protein within them causes one cell within each cluster to fully differentiate, yielding a single mature heterocyst. In symbiosis with plants, heterocyst frequencies are increased 3- to 10-fold because, we propose, either differentiation is initiated at an increased number of sites or resolution of differentiating clusters is incomplete. The physiology of symbiotically associated cyanobacteria raises the prospect that heterocyst differentiation proceeds independently of the nitrogen status of a cell and depends instead on signals produced by the plant partner.
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Affiliation(s)
- John C Meeks
- Section of Microbiology, University of California, Davis, California 95616, USA.
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Yoshimura H, Yanagisawa S, Kanehisa M, Ohmori M. Screening for the target gene of cyanobacterial cAMP receptor protein SYCRP1. Mol Microbiol 2002; 43:843-53. [PMID: 12085767 DOI: 10.1046/j.1365-2958.2002.02790.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The target genes for SYCRP1, a cyanobacterial cAMP receptor protein, were surveyed using a DNA microarray method. Total RNAs were extracted from a wild-type strain and a sycrp1 disruptant of Synechocystis sp. PCC 6803, and the respective gene expression levels were compared. The expression levels of six genes (slr1667, slr1168, slr2015, slr2016, slr2017 and slr2018) were clearly decreased by the disruption of the sycrp1 gene. The data suggest that slr1667 and slr1668 constitute one operon and the other four genes constitute another operon. Transcription start points for the first genes of these putative operons, which are slr1667 and slr2015, were determined by primer extension experiments. Gel mobility shift assays and DNase 1 footprint analyses were carried out to explore the binding of SYCRP1 to the putative promoter regions of slr1667 and slr2015. SYCRP1 bound to the specific site in the 5' upstream region of slr1667 from positions -170 to -155 relative to the transcription start point, while it did not bind to the 5' upstream region of slr2015. It was concluded that SYCRP1 regulates the expression of the slr1667 gene directly by binding to a specific site in its promoter.
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Affiliation(s)
- Hidehisa Yoshimura
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan
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18
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Intergenomic transcriptional interplays between plastid as a cyanobacterial symbiont and nucleus. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0921-0423(02)80047-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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19
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Khudyakov IY, Golden JW. Identification and inactivation of three group 2 sigma factor genes in Anabaena sp. strain PCC 7120. J Bacteriol 2001; 183:6667-75. [PMID: 11673438 PMCID: PMC95499 DOI: 10.1128/jb.183.22.6667-6675.2001] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three new Anabaena sp. strain PCC 7120 genes encoding group 2 alternative sigma factors have been cloned and characterized. Insertional inactivation of sigD, sigE, and sigF genes did not affect growth on nitrate under standard laboratory conditions but did transiently impair the abilities of sigD and sigE mutant strains to establish diazotrophic growth. A sigD sigE double mutant, though proficient in growth on nitrate and still able to differentiate into distinct proheterocysts, was unable to grow diazotrophically due to extensive fragmentation of filaments upon nitrogen deprivation. This double mutant could be complemented by wild-type copies of sigD or sigE, indicating some degree of functional redundancy that can partially mask phenotypes of single gene mutants. However, the sigE gene was required for lysogenic development of the temperate cyanophage A-4L. Several other combinations of double mutations, especially sigE sigF, caused a transient defect in establishing diazotrophic growth, manifested as a strong and prolonged bleaching response to nitrogen deprivation. We found no evidence for developmental regulation of the sigma factor genes. luxAB reporter fusions with sigD, sigE, and sigF all showed slightly reduced expression after induction of heterocyst development by nitrogen stepdown. Phylogenetic analysis of cyanobacterial group 2 sigma factor sequences revealed that they fall into several subgroups. Three morphologically and physiologically distant strains, Anabaena sp. strain PCC 7120, Synechococcus sp. strain PCC 7002, and Synechocystis sp. strain PCC 6803 each contain representatives of four subgroups. Unlike unicellular strains, Anabaena sp. strain PCC 7120 has three additional group 2 sigma factors that cluster in subgroup 2.5b, which is perhaps specific for filamentous or heterocystous cyanobacteria.
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Affiliation(s)
- I Y Khudyakov
- Department of biology, Texas A & M University, College Station 77843-3258, USA
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20
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Buikema WJ, Haselkorn R. Expression of the Anabaena hetR gene from a copper-regulated promoter leads to heterocyst differentiation under repressing conditions. Proc Natl Acad Sci U S A 2001; 98:2729-34. [PMID: 11226308 PMCID: PMC30207 DOI: 10.1073/pnas.051624898] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2000] [Indexed: 11/18/2022] Open
Abstract
Heterocyst differentiation in the filamentous cyanobacterium Anabaena PCC 7120 requires a functional hetR gene. Increased expression of the hetR gene is seen in developing and mature heterocysts in response to fixed nitrogen limitation. We mapped four likely transcriptional start sites for hetR and identified a specific transcript that is positively autoregulated. By using the copper-responsive petE promoter from Anabaena PCC 7120 to drive hetR expression, we show that ectopic expression of hetR increases heterocyst frequency and induces heterocyst differentiation under fully repressing conditions. Coexpression of a reporter gene shows that expression from the petE promoter is smoothly induced depending on the amount of copper supplied. In the heterocyst pattern mutant PatA, where terminally positioned heterocysts are formed almost exclusively, expression of the petEhetR fusion does not result in the formation of intercalary heterocysts. These results suggest that although the intracellular concentration of HetR has to be elevated for the differentiation decision, PatA plays a role as well. This role may be in the form of posttranslational modification of HetR, because PatA is a member of the response regulator family of proteins.
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Affiliation(s)
- W J Buikema
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA.
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21
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Muro-Pastor AM, Herrero A, Flores E. Nitrogen-regulated group 2 sigma factor from Synechocystis sp. strain PCC 6803 involved in survival under nitrogen stress. J Bacteriol 2001; 183:1090-5. [PMID: 11208809 PMCID: PMC94978 DOI: 10.1128/jb.183.3.1090-1095.2001] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The expression of sll1689, an open reading frame from the cyanobacterium Synechocystis sp. strain PCC 6803 putatively encoding a member of the sigma(70) family of sigma factors, appears to be regulated by the nitrogen control transcription factor NtcA. Disruption of sll1689 had no noticeable effect on exponential growth, identifying its product as a member of the group 2, nonessential class of sigma(70)-like sigma factors; however, this disruption decreased the viability of the cells after long periods of nitrogen starvation. We have named this gene rpoD2-V. The expression of glnN, encoding a type III glutamine synthetase, was impaired in strains bearing an inactivated copy of the rpoD2-V gene.
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Affiliation(s)
- A M Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, E-41092 Seville, Spain.
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22
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He Q, Dolganov N, Bjorkman O, Grossman AR. The high light-inducible polypeptides in Synechocystis PCC6803. Expression and function in high light. J Biol Chem 2001; 276:306-14. [PMID: 11024039 DOI: 10.1074/jbc.m008686200] [Citation(s) in RCA: 188] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
There are five Synechocystis PCC6803 genes encoding polypeptides with similarity to the Lhc polypeptides of plants. Four of the polypeptides, designated HliA-D (Dolganov, N. A. M., Bhaya, D., and Grossman, A. R. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 636-640) (corresponding to ScpC, ScpD, ScpB, and ScpE in Funk, C., and Vermaas, W. (1999) Biochemistry 38, 9397-9404) contain a single transmembrane domain. The fifth polypeptide (HemH) represents a fusion between a ferrochelatase and an Hli-like polypeptide. By using an epitope tag to identify specifically the different Hli polypeptides, the accumulation of each (excluding HemH) was examined under various environmental conditions. The levels of all of the Hli polypeptides were elevated in high light and during nitrogen limitation, whereas HliA, HliB, and HliC also accumulated to high levels following exposure to sulfur deprivation and low temperature. The temporal pattern of accumulation was significantly different among the different Hli polypeptides. HliC rapidly accumulated in high light, and its level remained high for at least 24 h. HliA and HliB also accumulated rapidly, but their levels began to decline 9-12 h following the imposition of high light. HliD was transiently expressed in high light and was not detected 24 h after the initiation of high light exposure. These results demonstrate that there is specificity to the accumulation of the Hli polypeptides under a diverse range of environmental conditions. Furthermore, mutants for the individual and combinations of the hli genes were evaluated for their fitness to grow in high light. Although all of the mutants grew as fast as wild-type cells in low light, strains inactivated for hliA or hliC/hliD were unable to compete with wild-type cells during co-cultivation in high light. A mutant lacking all four hli genes gradually lost its photosynthesis capacity and died in high light. Hence, the Hli polypeptides are critical for survival when Synechocystis PCC6803 is absorbing excess excitation energy and may allow the cells to cope more effectively with the production of reactive oxygen species.
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Affiliation(s)
- Q He
- Department of Plant Biology, The Carnegie Institution of Washington, Stanford, California 94305, USA.
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Affiliation(s)
- A Herrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, E-41092 Seville, Spain
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Adamska I. The Elip Family of Stress Proteins in the Thylakoid Membranes of Pro- and Eukaryota. REGULATION OF PHOTOSYNTHESIS 2001. [DOI: 10.1007/0-306-48148-0_28] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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25
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Abstract
When deprived of combined nitrogen, many filamentous cyanobacteria develop a one-dimensional pattern of specialised nitrogen-fixing cells, known as heterocysts. Recent years have seen the identification and characterisation of some of the key genes and proteins involved in heterocyst development and spacing, including the positive regulator HetR and the diffusible inhibitor PatS.
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Affiliation(s)
- D G Adams
- Division of Microbiology, School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
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26
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Abstract
Expression of plastid genes is controlled at both transcriptional and post-transcriptional levels in response to developmental and environmental signals. In many cases this regulation is mediated by nuclear-encoded proteins acting in concert with the endogenous plastid gene expression machinery. Transcription in plastids is accomplished by two distinct RNA polymerase enzymes, one of which resembles eubacterial RNA polymerases in both subunit structure and promoter recognition properties. The holoenzyme contains a catalytic core composed of plastid-encoded subunits, assembled with a nuclear-encoded promoter-specificity factor, sigma. Based on examples of transcriptional regulation in bacteria, it is proposed that differential activation of sigma factors may provide the nucleus with a mechanism to control expression of groups of plastid genes. Hence, much effort has focused on identifying and characterizing sigma-like factors in plants. While fractionation studies had identified several candidate sigma factors in purified RNA polymerase preparations, it was only 4 years ago that the first sigma factor genes were cloned from two photosynthetic eukaryotes, both of which were red algae. More recently this achievement has extended to the identification of families of sigma-like factor genes from several species of vascular plants. Now, efforts in the field are directed at understanding the roles in plastid transcription of each member of the rapidly expanding plant sigma factor gene family. Recent results suggest that accumulation of individual sigma-like factors is controlled by light, by plastid type and/or by a particular stage of chloroplast development. These data mesh nicely with accumulating evidence that the core sigma-binding regions of plastid promoters mediate regulated transcription in response to light-regime and plastid type or developmental state. In this review I will outline progress made to date in identifying and characterizing the sigma-like factors of plants, and in dissecting their potential roles in chloroplast gene expression.
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Affiliation(s)
- L A Allison
- Department of Biochemistry, University of Nebraska, NE 68588-0664, Lincoln, USA.
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27
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Jansson S, Andersson J, Kim SJ, Jackowski G. An Arabidopsis thaliana protein homologous to cyanobacterial high-light-inducible proteins. PLANT MOLECULAR BIOLOGY 2000; 42:345-351. [PMID: 10794534 DOI: 10.1023/a:1006365213954] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An Arabidopsis thaliana cDNA clone encoding a novel 110 amino acid thylakoid protein has been sequenced. The in vitro synthesized protein is taken up by intact chloroplasts, inserted into the thylakoid membrane and the transit peptide is cleaved off during this process. The mature protein is predicted to contain 69 amino acids, to form one membrane-spanning alpha-helix and to have its N-terminus at the stromal side of the thylakoid membrane. The protein showed similarity to the LHC, ELIP and PsbS proteins of higher plants, but more pronounced to the high-light-inducible proteins (HLIPs) of cyanobacteria and red algae, to which no homologue previously has been detected in higher plants. As for HLIP and ELIP, high light increases the mRNA levels of the corresponding gene. Sequence comparisons indicate that the protein may bind chlorophyll and form dimers in the thylakoid membrane. The level of expression of the protein seems to be far lower than that of normal PSI and PSII subunits.
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Affiliation(s)
- S Jansson
- Umeå Plant Science Center, Department of Plant Physiology, Umeå University, Sweden
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28
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Goto-Seki A, Shirokane M, Masuda S, Tanaka K, Takahashi H. Specificity crosstalk among group 1 and group 2 sigma factors in the cyanobacterium Synechococcus sp. PCC7942: In vitro specificity and a phylogenetic analysis. Mol Microbiol 1999; 34:473-84. [PMID: 10564489 DOI: 10.1046/j.1365-2958.1999.01608.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The chromosome of the cyanobacterium Synechococcus sp. PCC7942 contains at least one group 1 (rpoD1) and three group 2 (rpoD2, rpoD3 and rpoD4) sigma factor genes. In this study, we have analysed the structure of rpoD3 and rpoD4 and have shown that these genes are dispensable for growth at normal physiological conditions. An RNA polymerase core enzyme of the cyanobacterial strain was purified, reconstituted with the recombinant sigma factors (the rpoD1, rpoD3 and rpoD4 gene products), and the resultant holoenzymes were examined in vitro for transcription specificity. All of the holoenzymes recognized canonical promoters of Escherichia coli as well as cyanobacterial rrnA, cpcB1A1 P1a and rpoD1 promoters, although the three holoenzymes had some preference for specific promoters. These results suggest that group 1 as well as group 2 sigma factors of cyanobacteria may direct transcription initiation from the eubacterial consensus-type promoters containing the Pribnow -10 element, and we postulate that specificity crosstalk is a common characteristic among eubacterial group 1 and group 2 sigma factors. Phylogenetic analyses revealed that most group 2 sigma factors were positioned in one of four distinct clusters. The implication of the phylogenetic tree is also discussed in this paper.
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Affiliation(s)
- A Goto-Seki
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan
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29
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Tan S, Troxler RF. Characterization of two chloroplast RNA polymerase sigma factors from Zea mays: photoregulation and differential expression. Proc Natl Acad Sci U S A 1999; 96:5316-21. [PMID: 10220463 PMCID: PMC21861 DOI: 10.1073/pnas.96.9.5316] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two distinct cDNAs encoding putative sigma factors of plastid RNA polymerase were isolated from Zea mays, a C4 plant. The deduced amino acid sequences of both cDNAs possess all four highly conserved domains proposed for recognition of -10 and -35 promoter elements, core complex binding, DNA binding, and melting. These two cDNAs are designated sig1 and sig2. Phylogenetic analysis of available plastid sigma factors indicated that they were probably the descendants of cyanobacterial principal sigma factors. Southern blots probed with sig1 and sig2 revealed that both genes exist in the maize nuclear genome as single-copy genes, but low-stringency hybridization suggested the presence of a multigene family of maize plastid sigma factors. Transcription of sig1 and sig2 is light inducible and tissue specific. Transcripts of sig1 and sig2 were abundant in greening leaf tissues; sig2 (but not sig1) was barely detectable in etiolated leaves and neither was detectable in roots. Immunological studies using a peptide antibody against an epitope in subdomain 2.4 of Sig1 revealed 50-kDa and 60-kDa immunoreactive proteins in maize chloroplasts. Reduced levels of the 60-kDa immunoreactive protein were detected in etioplasts, and no immunoreactive proteins were observed in roots. Collectively, the data suggest that the nuclear genes, sig1 and sig2, may play a role in differential expression of plastid genes during chloroplast biogenesis.
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Affiliation(s)
- S Tan
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
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30
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Valladares A, Muro-Pastor AM, Fillat MF, Herrero A, Flores E. Constitutive and nitrogen-regulated promoters of the petH gene encoding ferredoxin:NADP+ reductase in the heterocyst-forming cyanobacterium Anabaena sp. FEBS Lett 1999; 449:159-64. [PMID: 10338123 DOI: 10.1016/s0014-5793(99)00404-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Determination of the putative transcription start points of the petH gene encoding ferredoxin:NADP+ reductase in the heterocyst-forming cyanobacteria Anabaena sp. PCC 7119 and PCC 7120 showed that this gene is transcribed from two promoters, one constitutively used under different conditions of nitrogen nutrition and the other one used in cells subjected to nitrogen stepdown and in nitrogen-fixing filaments. The latter promoter, whose use was NtcA-dependent but HetR-independent, was functional in heterocysts. The N-control transcriptional regulator NtcA was observed to bind in vitro to this promoter. For the sake of comparison, the transcription start points of the nifHDK operon in strain PCC 7120 and binding of NtcA to the nifHDK promoter were also examined.
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Affiliation(s)
- A Valladares
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Centro de Investigaciones Científicas Isla de la Cartuja, Spain
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31
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Abstract
Heterocystous cyanobacteria grow as multicellular organisms with a distinct one-dimensional developmental pattern of single nitrogen-fixing heterocysts separated by approximately ten vegetative cells. Several genes have been identified that are required for heterocyst development and pattern formation. A key regulator, HetR, has been recently shown to be aserine-type protease.
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Affiliation(s)
- J W Golden
- Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA.
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32
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Kestermann M, Neukirchen S, Kloppstech K, Link G. Sequence and expression characteristics of a nuclear-encoded chloroplast sigma factor from mustard (Sinapis alba). Nucleic Acids Res 1998; 26:2747-53. [PMID: 9592164 PMCID: PMC147615 DOI: 10.1093/nar/26.11.2747] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Plant chloroplasts contain transcription factors that functionally resemble bacterial sigma factors. We have cloned the full-length cDNA from mustard (Sinapis alba) for a 53 kDa derived polypeptide that contains similarity to regions 1.2-4.2 of sigma70-type factors. The amino acid sequence at the N-terminus has characteristics of a chloroplast transit peptide. An in vitro synthesized polypeptide containing this region was shown to be imported into the chloroplast and processed. The recombinant factor lacking the N-terminal extension was expressed in Escherichia coli and purified. It confers the ability on E.coli core RNA polymerase to bind specifically to a DNA fragment that contains the chloroplast psbA promoter. Transcription of the psbA template by E.coli core enzyme in the presence of recombinant SIG1 results in enhanced formation of transcripts of the size expected for correct initiation at the in vivo start site. Together, these data suggest that the mature protein acts as one of the chloroplast transcription factors in mustard. RNA gel blot hybridization reveals a transcript at approximately 1.8 kb, which is more abundant in light-grown than in dark-grown mustard seedlings.
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Affiliation(s)
- M Kestermann
- Plant Cell Physiology and Molecular Biology, University of Bochum, D-44780 Bochum, Germany
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33
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Oikawa K, Tanaka K, Takahashi H. Two types of differentially photo-regulated nuclear genes that encode sigma factors for chloroplast RNA polymerase in the red alga Cyanidium caldarium strain RK-1. Gene 1998; 210:277-85. [PMID: 9573383 DOI: 10.1016/s0378-1119(98)00075-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A nuclear gene, sigA, that encodes a sigma factor for chloroplast RNA polymerase has previously been identified and characterized in the primitive red alga Cyanidium caldarium strain RK-1. Southern hybridization analysis indicated the presence of two additional sigma factor genes, which have now been cloned and shown to encode virtually identical proteins that are homologous to eubacterial sigma factors. These genes, which are also present in the nuclear genome, have therefore been named sigB and sigC. The substantial sequence similarity of sigB and sigC to sigA of the same strain as well as to cyanobacterial principal sigma factors and other chloroplast sigma factors strongly suggests that the nuclear genome of C. caldarium contains three genes that encode two types of chloroplast sigma factors. Each of the three recombinant Sig proteins showed sigma factor activity in vitro when combined with the Escherichia coli RNA polymerase core enzyme. Northern blot analysis revealed that, whereas the overall abundance of sigA transcripts was not affected by light, the amount of sigB and sigC mRNAs was greater in the light than in the dark. Thus, multiple sigma factors appear to contribute to light-regulated gene expression in the chloroplast.
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Affiliation(s)
- K Oikawa
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan
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34
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Schyns G, Jia L, Coursin T, Tandeau de Marsac N, Houmard J. Promoter recognition by a cyanobacterial RNA polymerase: in vitro studies with the Calothrix sp. PCC 7601 transcriptional factors RcaA and RcaD. PLANT MOLECULAR BIOLOGY 1998; 36:649-659. [PMID: 9526497 DOI: 10.1023/a:1005983320006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To study the transcriptional apparatus and the mechanisms that control gene expression in cyanobacteria, the RNA polymerase was purified from the filamentous Calothrix sp. PCC 7601 and used in in vitro transcription assays. Conditions required for specific transcription initiation to occur were analyzed with the eleven Calothrix PCC 7601 genes for which the 5' ends have been mapped. Most of the transcripts directly obtained did not have the expected size, providing a test for looking at specific transcription factors. Addition of RcaA, a protein that binds to the promoter region of the phycobiliprotein cpeBA operon, restored accurate initiation of transcription in the in vitro system for three phycobiliprotein promoters. RcaA thus is a transcription factor that allows to mimick in vivo transcription. In parallel, the functional properties of the Escherichia coli and cyanobacterial RNA polymerases were compared. The enteric enzyme could not precisely initiate transcription at the promoter of a phycobiliprotein gene and, reciprocally, the cyanobacterial RNA polymerase could initiate transcription at PlacUV5, but not from wild-type Plac promoters. The different behaviours of the enzymes are discussed in the light of the structural differences that exist between subunits of the RNA polymerases.
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Affiliation(s)
- G Schyns
- Département de Biochimie et Génétique Moléculaire, Institut Pasteur, Paris, France
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35
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Isono K, Shimizu M, Yoshimoto K, Niwa Y, Satoh K, Yokota A, Kobayashi H. Leaf-specifically expressed genes for polypeptides destined for chloroplasts with domains of sigma70 factors of bacterial RNA polymerases in Arabidopsis thaliana. Proc Natl Acad Sci U S A 1997; 94:14948-53. [PMID: 9405719 PMCID: PMC25143 DOI: 10.1073/pnas.94.26.14948] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Genes for sigma-like factors of bacterial-type RNA polymerase have not been characterized from any multicellular eukaryotes, although they probably play a crucial role in the expression of plastid photosynthesis genes. We have cloned three distinct cDNAs, designated SIG1, SIG2, and SIG3, for polypeptides possessing amino acid sequences for domains conserved in sigma70 factors of bacterial RNA polymerases from the higher plant Arabidopsis thaliana. Each gene is present as one copy per haploid genome without any additional sequences hybridized in the genome. Transient expression assays using green fluorescent protein demonstrated that N-terminal regions of the SIG2 and SIG3 ORFs could function as transit peptides for import into chloroplasts. Transcripts for all three SIG genes were detected in leaves but not in roots, and were induced in leaves of dark-adapted plants in rapid response to light illumination. Together with results of our previous analysis of tissue-specific regulation of transcription of plastid photosynthesis genes, these results indicate that expressed levels of the genes may influence transcription by regulating RNA polymerase activity in a green tissue-specific manner.
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Affiliation(s)
- K Isono
- Laboratory of Plant Molecular Physiology, Research Institute of Innovative Technology for the Earth, 9-2 Kizugawadai, Kizu-cho, Soraku-gun, Kyoto 619-02, Japan
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36
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Caslake LF, Gruber TM, Bryant DA. Expression of two alternative sigma factors of Synechococcus sp. strain PCC 7002 is modulated by carbon and nitrogen stress. MICROBIOLOGY (READING, ENGLAND) 1997; 143 ( Pt 12):3807-3818. [PMID: 9421905 DOI: 10.1099/00221287-143-12-3807] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The sigB and sigC genes, encoding two alternative sigma factors of the unicellular marine cyanobacterium Synechococcus sp. PCC 7002, were cloned and characterized. Strains in which the sigB and sigC genes were insertionally inactivated were viable under standard laboratory conditions, indicating that SigB and SigC are group 2 sigma factors. Starvation for either nitrogen or carbon caused an increase in sigB mRNA levels. Transcripts for the sigC gene initially increased but then decreased during nitrogen and carbon starvation. The SigC protein could not be identified in cyanobacterial extracts using antisera to Synechococcus sp. PCC 7002 SigA or RpoD from Bacillus subtilis. The ratio of the principal vegetative sigma factor, SigA, to SigB decreased during either nitrogen starvation or carbon starvation, and the levels of SigB also increased in the sigC mutant strain. These results imply that SigB and SigC play roles in modifying transcription in response to changes in carbon and nitrogen availability in this cyanobacterium.
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Affiliation(s)
| | - Tanja M Gruber
- Department of Biochemistry and Molecular Biology and Center for Biomolecular Structure and Function, The Pennsylvania State University, University Park,PA 16802,USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology and Center for Biomolecular Structure and Function, The Pennsylvania State University, University Park,PA 16802,USA
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37
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Asayama M, Suzuki A, Nozawa S, Yamada A, Tanaka K, Takahashi H, Aida T, Shirai M. A new sigma factor homolog in a cyanobacterium: cloning, sequencing, and light-responsive transcripts of rpoD2 from Microcystis aeruginosa K-81. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1351:31-6. [PMID: 9116041 DOI: 10.1016/s0167-4781(97)00019-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We isolated an rpoD2 gene encoding the potential sigma factor of RNA polymerase from the cyanobacterium Microcystis aeruginosa K-81, which can perform photosynthesis. The deduced amino acid sequence of RpoD2 (sigmaA2) exhibits extensive homology to other eubacterial RpoD proteins. This gene possessed multiple 5'-end transcripts, expressed specifically under light (P(L)), dark (P(D)), or constitutively light/dark (P(C)) conditions during exponential cell growth.
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Affiliation(s)
- M Asayama
- Division of Biotechnology, School of Agriculture, Ibaraki University, Ami, Japan
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38
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Gruber TM, Bryant DA. Molecular systematic studies of eubacteria, using sigma70-type sigma factors of group 1 and group 2. J Bacteriol 1997; 179:1734-47. [PMID: 9045836 PMCID: PMC178889 DOI: 10.1128/jb.179.5.1734-1747.1997] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Sigma factors of the sigma70 family were used as a phylogenetic tool to compare evolutionary relationships among eubacteria. Several new sigma factor genes were cloned and sequenced to increase the variety of available sequences. Forty-two group 1 sigma factor sequences of various species were analyzed with the help of a distance matrix method to establish a phylogenetic tree. The tree derived by using sigma factors yielded subdivisions, including low-G+C and high-G+C gram-positive bacteria, cyanobacteria, and the alpha, beta, gamma, and delta subdivisions of proteobacteria, consistent with major bacterial groups found in trees derived from analyses with other molecules. However, some groupings (e.g., the chlamydiae, mycoplasmas, and green sulfur bacteria) are found in different positions than for trees obtained by using other molecular markers. A direct comparison to the most extensively used molecule in systematic studies, small-subunit rRNA, was made by deriving trees from essentially the same species set and using similar phylogenetic methods. Differences and similarities based on the two markers are discussed. Additionally, 31 group 2 sigma factors were analyzed in combination with the group 1 proteins in order to detect functional groupings of these alternative sigma factors. The data suggest that promoters recognized by the major vegetative sigma factors of eubacteria will contain sequence motifs and spacing very similar to those for the sigma70 sigma factors of Escherichia coli.
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Affiliation(s)
- T M Gruber
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park 16802, USA
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Asayama M, Kabasawa M, Shirai M. A novel genetic organization: the leuA-rpoD1 locus in the cyanobacterium Microcystis aeruginosa K-81. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1350:15-20. [PMID: 9003451 DOI: 10.1016/s0167-4781(96)00191-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We cloned and sequenced the region upstream of rpoD1, which encodes a principal sigma factor in the cyanobacterium Microcystis aeruginosa K-81. An open reading frame (orf1, 1599 bp) was discovered, the deduced amino-acid sequence of which (533 aa, 58, 016 Da) exhibits homology to another bacterial leuA gene product, 2-isopropylmalate synthase. The leuA (orf1) gene specifically complemented an E. coli leuA mutant. The 5'-upstream region of leuA did not contain possible leader peptide or stem-loop structures for attenuation. These findings indicate that the genetic structure of the leuA-rpoD1 locus in M. aeruginosa K-81 significantly differs from those of known leuA and rpoD loci found in other bacteria.
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Affiliation(s)
- M Asayama
- Laboratory of Molecular Microbiology, School of Agriculture, Ibaraki University, Japan
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Cai Y, Wolk CP. Anabaena sp. strain PCC 7120 responds to nitrogen deprivation with a cascade-like sequence of transcriptional activations. J Bacteriol 1997; 179:267-71. [PMID: 8982007 PMCID: PMC178688 DOI: 10.1128/jb.179.1.267-271.1997] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Anabaena sp. strain PCC 7120 adapts to deprivation of fixed nitrogen by undergoing physiological and genetic changes that include formation of N2-fixing heterocysts. Whether or not certain of the genes involved are interdependently expressed has been studied.
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Affiliation(s)
- Y Cai
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing 48824-1312, USA
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41
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Asayama M, Tanaka K, Takahashi H, Sato A, Aida T, Shirai M. Cloning, sequencing and characterization of the gene encoding a principal sigma factor homolog from the cyanobacterium Microcystis aeruginosa K-81. Gene 1996; 181:213-7. [PMID: 8973333 DOI: 10.1016/s0378-1119(96)00517-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We cloned and sequenced the rpoD1 gene of Microcystis aeruginosa K-81, a unicellular colony-forming cyanobacterium that can perform photosynthesis involving light-responsive gene expression. The deduced amino acid sequence of RpoD1 exhibited extensive homology to the other eubacterial principal sigma factors. Primer extension and Western blot analyses revealed that the rpoD1 gene, which encodes a principle sigma factor homolog, had two transcription start points, P1 and P2. These transcripts, and the corresponding protein, constitutively appeared in M. aeruginosa, irrespective of light or dark conditions.
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Affiliation(s)
- M Asayama
- Division of Biotechnology, School of Agriculture, Ibaraki University, Japan
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42
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Tanaka K, Oikawa K, Ohta N, Kuroiwa H, Kuroiwa T, Takahashi H. Nuclear encoding of a chloroplast RNA polymerase sigma subunit in a red alga. Science 1996; 272:1932-5. [PMID: 8658165 DOI: 10.1126/science.272.5270.1932] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A chloroplast RNA polymerase sigma factor is encoded by a nuclear gene, sigA, in the red alga Cyanidium caldarium RK-1. The encoded protein functions as an RNA polymerase sigma factor in vitro and it is localized to the chloroplast in vivo. SigA shows high sequence similarity to the sigma factors of cyanobacteria, which is indicative of the ancestral endosymbiotic event and subsequent transfer of the sigA gene to the nuclear genome.
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Affiliation(s)
- K Tanaka
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan
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43
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Brahamsha B. An abundant cell-surface polypeptide is required for swimming by the nonflagellated marine cyanobacterium Synechococcus. Proc Natl Acad Sci U S A 1996; 93:6504-9. [PMID: 8692845 PMCID: PMC39053 DOI: 10.1073/pnas.93.13.6504] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Certain marine unicellular cyanobacteria of the genus Synechococcus exhibit a unique and mysterious form of motility characterized by the ability to swim in liquid in the absence of flagella. An abundant cell-surface-associated polypeptide that is required for swimming motility by Synechococcus sp. strain WH8102 has been identified, and the gene encoding it, swmA, has been cloned and sequenced. The predicted SwmA protein contains a number of Ca2+-binding motifs as well as several potential N-glycosylation sites. Insertional inactivation of swmA in Synechococcus sp. strain WH8102 results in a loss of the ability to translocate, although the mutant strain, Swm-1, generates torque. This suggests that SwmA functions in the generation of thrust.
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Affiliation(s)
- B Brahamsha
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla 92093-0202, USA.
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44
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Talukder AA, Yanai S, Nitta T, Kato A, Yamada M. RpoS-dependent regulation of genes expressed at late stationary phase in Escherichia coli. FEBS Lett 1996; 386:177-80. [PMID: 8647276 DOI: 10.1016/0014-5793(96)00426-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have identified 6 Escherichia coli genomic genes, including 4 new genes, responsive to the stationary phase. One of them was regulated positively by RpoS at the stationary phase, and the remaining 5 negatively at a late stationary phase, all of them responding to multiple environmental stresses. Nucleotide sequences as well as such multiple responses revealed that those genes may have more than one overlapping-promoter recognized by different sigma-factors which regulate gene expressions during their cell growth.
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Affiliation(s)
- A A Talukder
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Japan
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Tsinoremas NF, Ishiura M, Kondo T, Andersson CR, Tanaka K, Takahashi H, Johnson CH, Golden SS. A sigma factor that modifies the circadian expression of a subset of genes in cyanobacteria. EMBO J 1996; 15:2488-95. [PMID: 8665856 PMCID: PMC450181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We isolated mutants affected in the circadian expression of the psbAI gene in Synechococcus sp. strain PCC 7942 using a strategy that tags the genomic locus responsible for the mutant phenotype. The search identified one short period (22 h) mutant (M2) and two low amplitude mutants, one of which showed apparent arhythmia (M11) and one that was still clearly rhythmic (M16). We characterized the disrupted locus of the low amplitude but still rhythmic mutant (M16) as the rpoD2 gene, a member of a gene family that encodes sigma70-like transcription factors in Synechococcus. We also inactivated rpoD2 in a number of reporter strains and showed that the circadian expression of some genes is not modified by the loss of this sigma factor. Therefore, we conclude that rpoD2 is a component of an output pathway of the biological clock that affects the circadian expression of a subset of genes in Synechococcus. This work demonstrates a direct link between a transcription factor and the manifestation of circadian gene expression.
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Affiliation(s)
- N F Tsinoremas
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
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46
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A model for cell type-specific differential gene expression during heterocyst development and the constitution of aerobic nitrogen fixation ability inAnabaena sp. strain PCC 7120. J Biosci 1996. [DOI: 10.1007/bf02703097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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47
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Liu B, Troxler RF. Molecular characterization of a positively photoregulated nuclear gene for a chloroplast RNA polymerase sigma factor in Cyanidium caldarium. Proc Natl Acad Sci U S A 1996; 93:3313-8. [PMID: 8622935 PMCID: PMC39604 DOI: 10.1073/pnas.93.8.3313] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We have cloned the gene for a putative chloroplast RNA polymerase sigma factor from the unicellular rhodophyte Cyanidium caldarium. This gene contains an open reading frame encoding a protein of 609 amino acids with domains highly homologous to all four conserved regions found in bacterial and cyanobacterial sigma 70-type subunits. When Southern blots of genomic DNA were hybridized to the "rpoD box" oligonucleotide probe, up to six hybridizing hands were observed. Transcripts of the sigma factor gene were undetectable in RNA from dark-grown cells but were abundant in the poly(A)+ fraction of RNA from illuminated cells. The sigma factor gene was expressed in Escherichia coli, and antibodies against the expressed sigma factor fusion protein cross-reacted with a 55-kDa protein in partially purified chloroplast RNA polymerase. Antibodies directed against a cyanobacterial RNA polymerase sigma factor also cross-reacted with a 55-kDa protein in the same enzyme preparation. Immunoprecipitation experiments showed that this enzyme preparation contains proteins with the same molecular weights as the alpha, beta, beta', and beta" subunits of chloroplast RNA polymerase in higher plants. This study identifies a gene for a plastid RNA polymerase sigma factor and indicates that there may be a family of nuclear-encoded sigma factors that recognize promoters in subsets of plastid genes and regulate differential gene expression at the transcriptional level.
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Affiliation(s)
- B Liu
- Department of Biochemistry, Boston University School of Medicine, MA 02118, USA
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Osborn AM, Bruce KD, Ritchie DA, Strike P. The sigA gene encoding the major sigma factor of RNA polymerase from the marine cyanobacterium Synechococcus sp. strain PCC 7002: cloning and characterization. MICROBIOLOGY (READING, ENGLAND) 1996; 142 ( Pt 2):337-345. [PMID: 8932708 DOI: 10.1099/13500872-142-2-347] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The gene encoding the principal sigma factor from Synechococcus sp. strain PCC 7002 was isolated and characterized. The Synechococcus sp. strain PCC 7002 sigA gene encodes a protein of 375 amino acids (43 center dot 7 kDa) that is required for viability under normal growth conditions. The SigA protein was overproduced in Escherichia coli and the purified protein was used to raise polyclonal antiserum in rabbits. This antiserum was used in immunoblot analyses of partially purified RNA polymerase from Synechococcus sp. strain PR6000. The probable in vivo translational start site was identified by a comparison of amino acid sequencing results obtained with SigA proteins overproduced in E. coli with immunoblot analyses of SigA protein in crude preparations of RNA polymerase from the cyanobacterium. The sigA gene is encoded on a transcript of 1700 bases that initiates 496 nucleotides upstream from the probable in vivo translational start site. The abundance of sigA transcripts decreases rapidly after the removal of combined nitrogen from the growth medium.
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Affiliation(s)
- A M Osborn
- Department of Genetics and Microbiology, Donnan Laboratories, University of Liverpool, PO Box 147, Liverpool L69 3BX, UK
| | - K D Bruce
- Department of Genetics and Microbiology, Donnan Laboratories, University of Liverpool, PO Box 147, Liverpool L69 3BX, UK
| | - D A Ritchie
- Department of Genetics and Microbiology, Donnan Laboratories, University of Liverpool, PO Box 147, Liverpool L69 3BX, UK
| | - P Strike
- Department of Genetics and Microbiology, Donnan Laboratories, University of Liverpool, PO Box 147, Liverpool L69 3BX, UK
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Ramasubramanian TS, Pu F, Golden JW. Isolation of the Anabaena sp. strain PCC 7120 sigA gene in a transcriptional-interference selection. J Bacteriol 1995; 177:6676-8. [PMID: 7592451 PMCID: PMC177526 DOI: 10.1128/jb.177.22.6676-6678.1995] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A transcriptional-interference selection was performed to identify genes of Anabaena sp. strain PCC 7120 that encode DNA-binding proteins able to bind to the rbcL promoter. Unexpectedly, the selection yielded the previously identified sigA gene, which encodes the principal sigma factor. Protein extracts from Escherichia coli containing the sigA gene bound the rbcL promoter fragment in mobility shift assays, and competition experiments indicated binding to rbcL and glnA but not xisA or nifH upstream regions.
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Affiliation(s)
- T S Ramasubramanian
- Department of Biology, Texas A&M University, College Station 77843-3258, USA
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50
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Green BR, Kühlbrandt W. Sequence conservation of light-harvesting and stress-response proteins in relation to the three-dimensional molecular structure of LHCII. PHOTOSYNTHESIS RESEARCH 1995; 44:139-148. [PMID: 24307033 DOI: 10.1007/bf00018304] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/1995] [Accepted: 02/16/1995] [Indexed: 06/02/2023]
Abstract
The structure of pea light-harvesting complex LHCII determined to 3.4 Å resolution by electron crystallography (Kühlbrandt, Wang and Fujiyoshi (1994) Nature 367: 614-621) was examined to determine the relationship between structural elements and sequence motifs conserved in the extended family of light-harvesting antennas (Chl a/b, fucoxanthin Chl a/c proteins) and membrane-intrinsic stress-induced proteins (ELIPs) to which LHCII belongs. It is predicted that the eukaryotic ELIPs can bind at least four molecules of Chl. The one-helix prokaryotic ELIP of Synechococcus was modelled as a homodimer based on the high degree of conservation of residues involved in the interactions of the first (B) and third (A) helices of LHCII.
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Affiliation(s)
- B R Green
- Department of Botany, University of British Columbia, V6T 1Z4, Vancouver, B.C., Canada
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