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Górska AM, Gouveia P, Borba AR, Zimmermann A, Serra TS, Carvalho P, Lourenço TF, Oliveira MM, Peterhänsel C, Saibo NJM. ZmOrphan94 Transcription Factor Downregulates ZmPEPC1 Gene Expression in Maize Bundle Sheath Cells. FRONTIERS IN PLANT SCIENCE 2021; 12:559967. [PMID: 33897718 PMCID: PMC8062929 DOI: 10.3389/fpls.2021.559967] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Spatial separation of the photosynthetic reactions is a key feature of C4 metabolism. In most C4 plants, this separation requires compartmentation of photosynthetic enzymes between mesophyll (M) and bundle sheath (BS) cells. The upstream region of the gene encoding the maize PHOSPHOENOLPYRUVATE CARBOXYLASE 1 (ZmPEPC1) has been shown sufficient to drive M-specific ZmPEPC1 gene expression. Although this region has been well characterized, to date, only few trans-factors involved in the ZmPEPC1 gene regulation were identified. Here, using a yeast one-hybrid approach, we have identified three novel maize transcription factors ZmHB87, ZmCPP8, and ZmOrphan94 as binding to the ZmPEPC1 upstream region. Bimolecular fluorescence complementation assays in maize M protoplasts unveiled that ZmOrphan94 forms homodimers and interacts with ZmCPP8 and with two other ZmPEPC1 regulators previously reported, ZmbHLH80 and ZmbHLH90. Trans-activation assays in maize M protoplasts unveiled that ZmHB87 does not have a clear transcriptional activity, whereas ZmCPP8 and ZmOrphan94 act as activator and repressor, respectively. Moreover, we observed that ZmOrphan94 reduces the trans-activation activity of both activators ZmCPP8 and ZmbHLH90. Using the electromobility shift assay, we showed that ZmOrphan94 binds to several cis-elements present in the ZmPEPC1 upstream region and one of these cis-elements overlaps with the ZmbHLH90 binding site. Gene expression analysis revealed that ZmOrphan94 is preferentially expressed in the BS cells, suggesting that ZmOrphan94 is part of a transcriptional regulatory network downregulating ZmPEPC1 transcript level in the BS cells. Based on both this and our previous work, we propose a model underpinning the importance of a regulatory mechanism within BS cells that contributes to the M-specific ZmPEPC1 gene expression.
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Affiliation(s)
- Alicja M. Górska
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
| | - Paulo Gouveia
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
| | - Ana Rita Borba
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
| | - Anna Zimmermann
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- Institut für Botanik, Leibniz Universität Hannover, Hannover, Germany
| | - Tânia S. Serra
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
| | - Pedro Carvalho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Tiago F. Lourenço
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
| | - M. Margarida Oliveira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
| | | | - Nelson J. M. Saibo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
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Russo MT, Annunziata R, Sanges R, Ferrante MI, Falciatore A. The upstream regulatory sequence of the light harvesting complex Lhcf2 gene of the marine diatom Phaeodactylum tricornutum enhances transcription in an orientation- and distance-independent fashion. Mar Genomics 2015; 24 Pt 1:69-79. [PMID: 26117181 DOI: 10.1016/j.margen.2015.06.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/31/2015] [Accepted: 06/17/2015] [Indexed: 10/23/2022]
Abstract
Diatoms are a key phytoplankton group in the contemporary ocean, showing extraordinary adaptation capacities to rapidly changing environments. The recent availability of whole genome sequences from representative species has revealed distinct features in their genomes, like novel combinations of genes encoding distinct metabolisms and a significant number of diatom-specific genes. However, the regulatory mechanisms driving diatom gene expression are still largely uncharacterized. Considering the wide variety of fields of study orbiting diatoms, ranging from ecology, evolutionary biology to biotechnology, it is thus essential to increase our understanding of fundamental gene regulatory processes such as transcriptional regulation. To this aim, we explored the functional properties of the 5'-flanking region of the Phaeodatylum tricornutum Lhcf2 gene, encoding a member of the Light Harvesting Complex superfamily and we showed that this region enhances transcription of a GUS reporter gene in an orientation- and distance-independent fashion. This represents the first example of a cis-regulatory sequence with enhancer-like features discovered in diatoms and it is instrumental for the generation of novel genetic tools and diatom exploitation in different areas of study.
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Affiliation(s)
| | - Rossella Annunziata
- Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine, UMR 7238, F-75006 Paris, France; CNRS, UMR 7238, F-75006 Paris, France
| | - Remo Sanges
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | | | - Angela Falciatore
- Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine, UMR 7238, F-75006 Paris, France; CNRS, UMR 7238, F-75006 Paris, France.
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Tolley BJ, Woodfield H, Wanchana S, Bruskiewich R, Hibberd JM. Light-regulated and cell-specific methylation of the maize PEPC promoter. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1381-90. [PMID: 22143916 PMCID: PMC3276097 DOI: 10.1093/jxb/err367] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 10/10/2011] [Accepted: 10/21/2011] [Indexed: 05/21/2023]
Abstract
The molecular mechanisms governing PEPC expression in maize remain to be fully defined. Differential methylation of a region in the PEPC promoter has been shown to correlate with transcript accumulation, however, to date, investigations into the role of DNA methylation in maize PEPC expression have relied on the use of methylation-sensitive restriction enzymes. Bisulphite sequencing was used here to provide a single-base resolution methylation map of the maize PEPC promoter. It is shown that four cytosine residues in the PEPC promoter are heavily methylated in maize root tissue. In leaves, de-methylation of these cytosines is dependent on illumination and is coincident with elevated PEPC expression. Furthermore, light-regulated de-methylation of these cytosines occurs only in mesophyll cells. No methylation was discovered in the 0.6 kb promoter required for mesophyll-specific expression indicating that cytosine methylation is not required to direct the cell-specificity of PEPC expression. This raises interesting questions regarding the function of the cell-specific cytosine de-methylation observed in the upstream region of the PEPC promoter.
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Affiliation(s)
- Ben J. Tolley
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Helen Woodfield
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Samart Wanchana
- International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines
| | - Richard Bruskiewich
- International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines
| | - Julian M. Hibberd
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
- To whom the correspondence should be addressed. E-mail:
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Londe LN, Ueira-Vieira C, Kerr WE, Bonetti AM. Characterization of DNA polymorphisms in Caryocar brasiliense in populations with and without thorn at the endocarp by RAPD markers. AN ACAD BRAS CIENC 2011; 82:779-89. [PMID: 21562705 DOI: 10.1590/s0001-37652010000300024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Accepted: 04/08/2010] [Indexed: 11/22/2022] Open
Abstract
Caryocar brasiliense (pequi), is one of the main species at the biome of the Brazilian savannah due to its use in culinary, popular medicine, industry in general, and iron and steel industry. At São José do Xingu (MT), a tree of C. brasiliense without thorn at the endocarp was found, which enables the improvement of C. brasiliense not only for consumption but also to the high appreciation it already has. To detect the existing differences between the pequi with and without the thorn at the endocarp, RADP markers were used. The generated polymorphisms were cloned and sequenced in order to identify the sequences that are responsible for the fenotypical alteration. It was observed that the pequi without thorn is genetically isolated from the other populations of pequi with thorn at the endocarp, proving that this characteristic is related to the genetic divergence of the species. Analysis in BLASTn evidenced the similarity of the Dof1 genes of Zea mays to its gene of phosphinotricin acetyl transferase. In the analysis of BLASTx, the similarity was verified to the proteins responsible for the deficiency in ferric reductase 4, and catalase.
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Affiliation(s)
- Luciana N Londe
- Empresa de Pesquisa Agropecuária de Minas Gerais, Laboratório de Biotecnologia, Nova Porteirinha, MG, Brazil.
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Yanagisawa S, Akiyama A, Kisaka H, Uchimiya H, Miwa T. Metabolic engineering with Dof1 transcription factor in plants: Improved nitrogen assimilation and growth under low-nitrogen conditions. Proc Natl Acad Sci U S A 2004; 101:7833-8. [PMID: 15136740 PMCID: PMC419692 DOI: 10.1073/pnas.0402267101] [Citation(s) in RCA: 199] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Utilization of transcription factors might be a powerful approach to modification of metabolism for a generation of crops having superior characteristics because a single transcription factor frequently regulates coordinated expression of a set of key genes for respective pathways. Here, we apply the plant-specific Dof1 transcription factor to improve nitrogen assimilation, the essential metabolism including the primary assimilation of ammonia to carbon skeletons to biosynthesize amino acids and other organic compounds involving nitrogen in plants. Expressing Dof1 induced the up-regulation of genes encoding enzymes for carbon skeleton production, a marked increase of amino acid contents, and a reduction of the glucose level in transgenic Arabidopsis. The results suggest cooperative modification of carbon and nitrogen metabolisms on the basis of their intimate link. Furthermore, elementary analysis revealed that the nitrogen content increased in the Dof1 transgenic plants (approximately 30%), indicating promotion of net nitrogen assimilation. Most significantly, the Dof1 transgenic plants exhibit improved growth under low-nitrogen conditions, an agronomically important trait. These results highlight the great utility of transcription factors in engineering metabolism in plants.
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Affiliation(s)
- Shuichi Yanagisawa
- Research Institute for Bioresources, Okayama University, Kurashiki 710-0046, Japan.
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Koizumi N, Toyota K, Kitajima S, Yamada Y, Sato F. Genomic structure and promoter analysis of phosphoenolpyruvate carboxylase in a C3 plant, Nicotiana sylvestris. Biosci Biotechnol Biochem 2002; 66:1691-6. [PMID: 12353629 DOI: 10.1271/bbb.66.1691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Three genes encoding phosphoenolpyruvate carboxylase were isolated from Nicotiana sylvestris and designated Nsppc1-3. Sequencing of nucleotides showed that the coding sequence and deduced amino acid sequences were highly conserved among the genes, but sequences for noncoding regions including introns and 5'-flanking regions were not conserved. Analysis of the transcript level of the genes by a combination of reverse transcriptase-PCR and restriction fragment polymorphism showed mostNsppc1 in the leaves, stems, roots, and cultured cells of N. sylvestris. beta-Glucuronidase activity was detected histochemically in mesophyll cells in leaves, lateral buds, and vascular bundles in roots of transgenic tobacco harboring a chimeric construct of the Nsppc1 promoter and the gene for beta-glucuronidase. Deletion analysis indicated the presence of a silencer-like element for basal expression in the promoter region of Nsppc1.
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Affiliation(s)
- Nozomu Koizumi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Japan
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Rydz SK, Prieto JL, Rychter AM, Vidal J. A DNA-binding activity for the promoter of the gene encoding C(4) phosphoenolpyruvate carboxylase is modulated by phosphorylation during greening of the Sorghum leaf. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2000; 159:65-73. [PMID: 11011094 DOI: 10.1016/s0168-9452(00)00327-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Electrophoresis mobility shift assay (EMSA) identified nuclear proteins with binding activity to a 430 bp promoter fragment of the Sorghum C(4) phosphoenolpyruvate carboxylase gene (SvC4). The DNA binding activities (two main retarded bands; PC1 and PC2) were high in nuclear extracts from etiolated leaves, decreased during greening and became very low or null in nuclear extracts from green leaves. This process was found to be mediated by phytochrome and was apparently irreversible since the DNA-binding activities were not restored in green plants kept in continuous darkness. The AT-rich region of the promoter fragment was identified to be the interaction domain of PC2. The detection of PC2 with EMSA was markedly reduced by preincubation of nuclear protein extracts with Mg-ATP or Mg-GTP and restored in the presence of a general protein serine/threonine-kinase inhibitor, K252a. The results suggested that the PC2 binding activity was modulated by phosphorylation during the greening process of the Sorghum leaf.
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Affiliation(s)
- SK Rydz
- Institut de Biotechnologie des Plantes, UMR CNRS 8618, Université de Paris-Sud, bâtiment 630, 91405 Cedex, Orsay, France
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Yanagisawa S. Dof1 and Dof2 transcription factors are associated with expression of multiple genes involved in carbon metabolism in maize. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2000; 21:281-8. [PMID: 10758479 DOI: 10.1046/j.1365-313x.2000.00685.x] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Dof proteins are transcription factors that appear to be unique to plants. Maize Dof1 has been suggested to be a regulator for C4 photosynthetic phosphoenolpyruvate carboxylase (C4PEPC) gene expression. The present study demonstrates that Dof1 also enhances transcription from the promoters of both cytosolic orthophosphate dikinase (cyPPDK) genes and a non-photosynthetic PEPC gene, which are not present in animals. Expression of Dof1-specific antisense RNA or the DNA-binding domain of Dof1 alone reduced the activities of these promoters in maize leaf protoplasts. Electrophoretic mobility shift assays revealed several Dof1-binding sites in these promoters. The cyppdk1 promoter contained two Dof1-binding sites, one of which was linked to the binding site of a plant bZIP protein. By using deleted or mutated cyppdk1 promoters, both Dof1-binding sites were shown to be functional. Furthermore, Dof1 elevated the activities of the cyppdk and pepc promoters more strongly in greening protoplasts than in etiolated protoplasts, in accordance with the different activities of these promoters in two types of protoplasts. Another Dof protein of maize, Dof2, suppressed the activity of the C4pepc promoter but was able to activate certain other promoters. These results suggest that Dof proteins may play regulatory roles in multiple gene expressions associated with the plant-specific pathway for carbon metabolism in maize. In addition, the primary characteristic of Dof proteins, i.e. different activities in distinct types of cells and opposite actions on promoters in different contexts, suggests the potential of Dof proteins to differentially regulate diverse promoters in a variety of plant tissues. Speculation raised by these results concerning the evolution of the C4pepc gene is also discussed.
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Affiliation(s)
- S Yanagisawa
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan.
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9
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Yanagisawa S. Dof DNA-binding domains of plant transcription factors contribute to multiple protein-protein interactions. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 250:403-10. [PMID: 9428691 DOI: 10.1111/j.1432-1033.1997.0403a.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Dof proteins are a family of plant transcription factors that have a strongly conserved DNA-binding domain, designated the Dof domain. This domain has the potential to form a single zinc finger. This report describes the self-association of a maize Dof protein, Dof1 (previously designated MNB1a). Affinity chromatography revealed that Dof1 also interacted with another maize Dof protein, Dof2, as well as with high-mobility-group (HMG) protein 1. Results of mapping of the region required for the protein-protein interactions of Dof1 suggested that these interactions may be mediated by the Dof domain. When gel mobility shift assays were performed with purified recombinant Dof proteins, homomeric and heteromeric complexes of Dof proteins on DNA were detected. It seems possible that formation of complexes of different Dof proteins through direct protein-protein interactions might be involved in the regulation of transcription. Evidence is also presented that HMG1 has an effect on the binding of Dof1 to DNA. Therefore, it appears that the Dof domain is a multifunctional domain that is involved not merely in binding to DNA but also in multiple protein-protein interactions.
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Affiliation(s)
- S Yanagisawa
- Department of Life Sciences (Chemistry), Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Japan
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Chen G, Rothnie HM, He X, Hohn T, Fütterer J. Efficient transcription from the rice tungro bacilliform virus promoter requires elements downstream of the transcription start site. J Virol 1996; 70:8411-21. [PMID: 8970962 PMCID: PMC190930 DOI: 10.1128/jvi.70.12.8411-8421.1996] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Elements downstream of the transcription start site enhance the activity of the rice tungro bacilliform virus (RTBV) promoter in protoplasts derived from cultured rice cells. This enhancer region was located to the first 90 nucleotides of the RTBV leader sequence. Within this region, at least two components which act together to enhance expression from the RTBV promoter could be identified. One is a position- and orientation-independent DNA element within a CT-rich region, and the other is a position-dependent element. Either element was found to be capable of acting independently on a heterologous promoter. The enhancer activity of the DNA element correlates with specific binding of nuclear proteins. Nuclear proteins also recognize an RNA transcript covering the first 90 nucleotides of the RTBV leader.
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Affiliation(s)
- G Chen
- Friedrich Miescher-Institut, Basel, Switzerland
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11
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Abstract
MNB1a is a DNA-binding protein from maize that interacts with the 35S promoter of cauliflower mosaic virus. This protein did not show significant homologies with any other DNA-binding protein and MNB1a seemed to be a member of a multigene family. In this study, isolation of cDNAs from the gene family to which MNB1a belongs revealed a unique conserved domain, referred to herein as the Dof domain, that contains a novel cysteine-rich motif for a single putative zinc finger. The amino acid sequence of the Dof domain and the arrangement of cysteine residues in this domain differ from those of known zinc finger motifs. However, the Dof domain was shown to be a DNA-binding domain that required Zn2+ ions for activity. Mutations at cysteine residues eliminated the DNA-binding activity of MNB1a. Thus, the Dof domain may be classified as a novel zinc finger motif. In addition, Southern blot analysis and a survey of DNA databases suggested that proteins that include Dof domains might exist in other eukaryotes, at least in the plant kingdom.
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Affiliation(s)
- S Yanagisawa
- Department of Life Sciences (Chemistry), Graduate School of Arts and Sciences, University of Tokyo, Japan
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12
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Rajagopalan AV, Devi MT, Raghavendra AS. Molecular biology of C4 phosphoenolpyruvate carboxylase: Structure, regulation and genetic engineering. PHOTOSYNTHESIS RESEARCH 1994; 39:115-135. [PMID: 24311065 DOI: 10.1007/bf00029380] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/1993] [Accepted: 11/01/1993] [Indexed: 06/02/2023]
Abstract
Three to four families of nuclear genes encode different isoforms of phosphoenolpyruvate (PEP) carboxylase (PEPC): C4-specific, C3 or etiolated, CAM and root forms. C4 leaf PEPC is encoded by a single gene (ppc) in sorghum and maize, but multiple genes in the C4-dicot Flaveria trinervia. Selective expression of ppc in only C4-mesophyll cells is proposed to be due to nuclear factors, DNA methylation and a distinct gene promoter. Deduced amino acid sequences of C4-PEPC pinpoint the phosphorylatable serine near the N-terminus, C4-specific valine and serine residues near the C-terminus, conserved cysteine, lysine and histidine residues and PEP binding/catalytic sites. During the PEPC reaction, PEP and bicarbonate are first converted into carboxyphosphate and the enolate of pyruvate. Carboxyphosphate decomposes within the active site into Pi and CO2, the latter combining with the enolate to form oxalacetate. Besides carboxylation, PEPC catalyzes a HCO3 (-)-dependent hydrolysis of PEP to yield pyruvate and Pi. Post-translational regulation of PEPC occurs by a phosphorylation/dephosphorylation cascade in vivo and by reversible enzyme oligomerization in vitro. The interrelation between phosphorylation and oligomerization of the enzyme is not clear. PEPC-protein kinase (PEPC-PK), the enzyme responsible for phosphorylation of PEPC, has been studied extensively while only limited information is available on the protein phosphatase 2A capable of dephosphorylating PEPC. The C4 ppc was cloned and expressed in Escherichia coli as well as tobacco. The transformed E. coli produced a functional/phosphorylatable C4 PEPC and the transgenic tobacco plants expressed both C3 and C4 isoforms. Site-directed mutagenesis of ppc indicates the importance of His(138), His(579) and Arg(587) in catalysis and/or substrate-binding by the E. coli enzyme, Ser(8) in the regulation of sorghum PEPC. Important areas for further research on C4 PEPC are: mechanism of transduction of light signal during photoactivation of PEPC-PK and PEPC in leaves, extensive use of site-directed mutagenesis to precisely identify other key amino acid residues, changes in quarternary structure of PEPC in vivo, a high-resolution crystal structure, and hormonal regulation of PEPC expression.
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Affiliation(s)
- A V Rajagopalan
- School of Life Sciences, University of Hyderabad, 500 134, Hyderabad, India
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Shimada H, Ohta H, Masuda T, Shioi Y, Takamiya K. A putative transcription factor binding to the upstream region of the puf operon in Rhodobacter sphaeroides. FEBS Lett 1993; 328:41-4. [PMID: 8344432 DOI: 10.1016/0014-5793(93)80961-s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Gel shift assays of the upstream region of the puf operon in Rhodobacter sphaeroides were performed using cell-free extracts from cells grown under various culture conditions. The results suggested that a protein binding to the upstream region functioned as a repressor-like substance of the expression of the operon by oxygen tension or light. The density of the shifted band of cell-free extracts from cells irradiated with blue light under semi-aerobic conditions was higher than that with red light. Phosphatase treatment of the cell-free extracts strongly increased the DNA-binding affinity of the protein.
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Affiliation(s)
- H Shimada
- Department of Biological Sciences, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan
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14
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Yanagisawa S, Izui K. Molecular cloning of two DNA-binding proteins of maize that are structurally different but interact with the same sequence motif. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)82353-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Lepiniec L, Keryer E, Philippe H, Gadal P, Crétin C. Sorghum phosphoenolpyruvate carboxylase gene family: structure, function and molecular evolution. PLANT MOLECULAR BIOLOGY 1993; 21:487-502. [PMID: 8443342 DOI: 10.1007/bf00028806] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Although housekeeping functions have been shown for the phosphoenolpyruvate carboxylase (EC 4.1.1.31, PEPC) in plants and in prokaryotes, PEPC is mainly known for its specific role in the primary photosynthetic CO2 fixation in C4 and CAM plants. We have shown that in Sorghum, a monocotyledonous C4 plant, the enzyme is encoded in the nucleus by a small multigene family. Here we report the entire nucleotide sequence (7.5 kb) of the third member (CP21) that completes the structure of the Sorghum PEPC gene family. Nucleotide composition, CpG islands and GC content of the three Sorghum PEPC genes are analysed with respect to their possible implications in the regulation of expression. A study of structure/function and phylogenetic relationships based on the compilation of all PEPC sequences known so far is presented. Data demonstrated that: (1) the different forms of plant PEPC have very similar primary structures, functional and regulatory properties, (2) neither apparent amino acid sequences nor phylogenetic relationships are specific for the C4 and CAM PEPCs and (3) expression of the different genes coding for the Sorghum PEPC isoenzymes is differently regulated (i.e. by light, nitrogen source) in a spatial and temporal manner. These results suggest that the main distinguishing feature between plant PEPCs is to be found at the level of genes expression rather than in their primary structure.
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Affiliation(s)
- L Lepiniec
- Laboratoire de Physiologie Végétale Moléculaire (URA-CNRS, 1128), Université de Paris-Sud, Orsay, France
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Albert HA, Martin T, Sun SS. Structure and expression of a sugarcane gene encoding a housekeeping phosphoenolpyruvate carboxylase. PLANT MOLECULAR BIOLOGY 1992; 20:663-671. [PMID: 1450381 DOI: 10.1007/bf00046451] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A gene (SCPEPCD1) encoding phosphoenolpyruvate carboxylase (PEPC) was isolated from the C-4 monocot sugarcane (Saccharum hybrid var. H32-8560). SCPEPCD1 is ca. 6800 bp long, with 10 exons. The entire gene sequence from -1561 to 262 bp downstream of the putative poly(A) addition signal is reported. A low-level, essentially constitutive pattern of expression, amino acid sequence similarities to other 'housekeeping' PEPC enzymes, and the absence of DNA sequence elements conserved in the upstream region of maize and sorghum C-4-specific PEPC genes indicate that SCPEPCD1 encodes a housekeeping PEPC. Despite this, a motif proposed to act as a phosphorylation site in light-mediated activation of photosynthetic PEPC enzymes [10] is present in the SCPEPCD1 protein; evidence is presented for the presence of this site in other housekeeping PEPC proteins.
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Affiliation(s)
- H A Albert
- Department of Plant Molecular Physiology, University of Hawaii, Honolulu 96822
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Yanagisawa S, Izui K. MNF1, a leaf tissue-specific DNA-binding protein of maize, interacts with the cauliflower mosaic virus 35S promoter as well as the C4 photosynthetic phosphoenolpyruvate carboxylase gene promoter. PLANT MOLECULAR BIOLOGY 1992; 19:545-53. [PMID: 1627769 DOI: 10.1007/bf00026781] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
When gel shift assays were performed with maize nuclear extract and a DNA fragment containing the cauliflower mosaic virus (CaMV) 35S promoter, three DNA-protein complexes were observed. Analyses with nuclear extracts prepared from green leaves, etiolated leaves, stems and roots showed that the complexes resulted from the existence of at least two nuclear factors. One of them is presumably a constitutive nuclear factor found in all tissues tested, and another is a leaf-specific factor present both in green and etiolated leaves. This leaf-specific nuclear factor seemed to be identical to MNF1, previously identified as a factor interacting with the promoter of the maize gene for phosphoenolpyruvate carboxylase involved in the C4 photosynthesis. Deletion analysis revealed that MNF1 binds to the sequence from -281 to -235 relative to the transcription start site of the CaMV 35S promoter. MNF1-like nuclear protein was also found in tobacco nuclear extracts. The possibility that MNF1 participates as a positive trans-acting factor in the expression of genes in maize leaves is discussed.
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Affiliation(s)
- S Yanagisawa
- Department of Chemistry, Faculty of Science, Kyoto University, Japan
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