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Irieda H, Shiomi D. ARC6-mediated Z ring-like structure formation of prokaryote-descended chloroplast FtsZ in Escherichia coli. Sci Rep 2017; 7:3492. [PMID: 28615720 DOI: 10.1038/s41598-017-03698-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/04/2017] [Indexed: 12/04/2022] Open
Abstract
Plant chloroplasts proliferate through binary fission, and the stromal-side molecules that are involved in chloroplast division are bacterial derivatives. As in bacteria, the prokaryotic tubulin homolog FtsZ assembles into a ring-like structure (Z ring) at mid-chloroplast, and this process is followed by constriction. However, the properties of chloroplast FtsZs remain unclarified. Here, we employed Escherichia coli as a novel heterologous system for expressing chloroplast FtsZs and their regulatory components. Fluorescently labelled Arabidopsis FtsZ2 efficiently assembled into long filaments in E. coli cells, and artificial membrane tethering conferred FtsZ2 filaments with the ability to form Z ring-like structures resembling the bacterial Z ring. A negative regulator of chloroplast FtsZ assembly, ARC3, retained its inhibitory effects on FtsZ2 filamentation and Z ring-like structure formation in E. coli cells. Thus, we provide a novel heterologous system by using bacterial cells to study the regulation of the chloroplast divisome. Furthermore, we demonstrated that the FtsZ2-interacting protein ARC6, which is a potential candidate for Z ring tethering to the chloroplast inner envelope membrane, genuinely targeted FtsZ2 to the membrane components and supported its morphological shift from linear filaments to Z ring-like structures in a manner dependent on the C-terminal ARC6-interacting domain of FtsZ2.
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Chikkala VRN, Nugent GD, Stalker DM, Mouradov A, Stevenson TW. Expression of Brassica oleracea FtsZ1-1 and MinD alters chloroplast division in Nicotiana tabacum generating macro- and mini-chloroplasts. Plant Cell Rep 2012; 31:917-28. [PMID: 22193339 DOI: 10.1007/s00299-011-1212-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 12/02/2011] [Accepted: 12/11/2011] [Indexed: 05/31/2023]
Abstract
FtsZ1-1 and MinD plastid division-related genes were identified and cloned from Brassica oleracea var. botrytis. Transgenic tobacco plants expressing BoFtsZ1-1 or BoMinD exhibited cells with either fewer but abnormally large chloroplasts or more but smaller chloroplasts relative to wild-type tobacco plants. An abnormal chloroplast phenotype in guard cells was found in BoMinD transgenic tobacco plants but not in BoFtsZ1-1 transgenic tobacco plants. Transgenic tobacco plants bearing the macro-chloroplast phenotype had 10 to 20-fold increased levels of total FtsZ1-1 or MinD, whilst the transgenic tobacco plants bearing the mini-chloroplast phenotype had lower increased FtsZ1-1 or absence of detectable MinD. We also described for the first time, plastid transformation of macro-chloroplast bearing tobacco shoots with a gene cassette allowing for expression of green fluorescent protein (GFP). Homoplasmic plastid transformants from normal chloroplast and macro-chloroplast tobacco plants expressing GFP were obtained. Both types of transformants accumulated GFP at ~6% of total soluble protein, thus indicating that cells containing macro-chloroplasts can regenerate shoots in tissue culture and can stably integrate and express a foreign gene to similar levels as plant cells containing a normal chloroplast size and number.
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Affiliation(s)
- Veera R N Chikkala
- School of Applied Sciences, RMIT University, Bundoora, VIC 3083, Australia
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3
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Smith AG, Johnson CB, Vitha S, Holzenburg A. Plant FtsZ1 and FtsZ2 expressed in a eukaryotic host: GTPase activity and self-assembly. FEBS Lett 2010; 584:166-72. [PMID: 19925792 DOI: 10.1016/j.febslet.2009.11.044] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 11/06/2009] [Accepted: 11/11/2009] [Indexed: 11/19/2022]
Abstract
Plants and algae contain the FtsZ1 and FtsZ2 protein families that perform specific, non-redundant functions in plastid division. In vitro studies of chloroplast division have been hampered by the lack of a suitable expression system. Here we report the expression and purification of FtsZ1-1 and FtsZ2-1 from Arabidopsis thaliana using a eukaryotic host. Specific GTPase activities were determined and found to be different for FtsZ1-1 vs. FtsZ2-1. The purified proteins readily assembled into previously unreported assembly products named type-I and -II filaments. In contrast to bacterial FtsZ, the Arabidopsis proteins do not form bundled sheets in the presence of Ca(2+).
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Affiliation(s)
- Aaron G Smith
- Microscopy and Imaging Center, Texas A&M University, College Station, TX 77843-2257, USA
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Maggi S, Massidda O, Luzi G, Fadda D, Paolozzi L, Ghelardini P. Division protein interaction web: identification of a phylogenetically conserved common interactome between Streptococcus pneumoniae and Escherichia coli. Microbiology (Reading) 2008; 154:3042-3052. [DOI: 10.1099/mic.0.2008/018697-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Silvia Maggi
- Dipartimento di Biologia, Università Tor Vergata, Roma, Italy
| | - Orietta Massidda
- Dipartimento di Scienze e Tecnologie Biomediche, Sez. Microbiologia Medica, Cagliari, Italy
| | - Giuseppe Luzi
- Dipartimento di Medicina Interna, Facoltà di Medicina, Università La Sapienza, Roma, Italy
| | - Daniela Fadda
- Dipartimento di Scienze e Tecnologie Biomediche, Sez. Microbiologia Medica, Cagliari, Italy
| | | | - Patrizia Ghelardini
- Istituto di Biologia e Patologia Molecolare del CNR, Roma, Italy
- Dipartimento di Biologia, Università Tor Vergata, Roma, Italy
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Yoder DW, Kadirjan-Kalbach D, Olson BJSC, Miyagishima SY, Deblasio SL, Hangarter RP, Osteryoung KW. Effects of mutations in Arabidopsis FtsZ1 on plastid division, FtsZ ring formation and positioning, and FtsZ filament morphology in vivo. Plant Cell Physiol 2007; 48:775-91. [PMID: 17468127 DOI: 10.1093/pcp/pcm049] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
In plants, chloroplast division FtsZ proteins have diverged into two families, FtsZ1 and FtsZ2. FtsZ1 is more divergent from its bacterial counterparts and lacks a C-terminal motif conserved in most other FtsZs. To begin investigating FtsZ1 structure-function relationships, we first identified a T-DNA insertion mutation in the single FtsZ1 gene in Arabidopsis thaliana, AtFtsZ1-1. Homozygotes null for FtsZ1, though impaired in chloroplast division, could be isolated and set seed normally, indicating that FtsZ1 is not essential for viability. We then mapped five additional atftsZ1-1 alleles onto an FtsZ1 structural model and characterized chloroplast morphologies, FtsZ protein levels and FtsZ filament morphologies in young and mature leaves of the corresponding mutants. atftsZ1-1(G267R), atftsZ1-1(R298Q) and atftsZ1-1(Delta404-433) exhibit reduced FtsZ1 accumulation but wild-type FtsZ2 levels. The semi-dominant atftsZ1-1(G267R) mutation caused the most severe phenotype, altering a conserved residue in the predicted T7 loop. atftsZ1-1(G267R) protein accumulates normally in young leaves but is not detected in rings or filaments. atftsZ1-1(R298Q) has midplastid FtsZ1-containing rings in young leaves, indicating that R298 is not critical for ring formation or positioning despite its conservation. atftsZ1-1(D159N) and atftsZ1-1(G366A) both have overly long, sometimes spiral-like FtsZ filaments, suggesting that FtsZ dynamics are altered in these mutants. However, atftsZ1-1(D159N) exhibits loss of proper midplastid FtsZ positioning while atftsZ1-1(G366A) does not. Finally, truncation of the FtsZ1 C-terminus in atftsZ1-1(Delta404-433) impairs chloroplast division somewhat but does not prevent midplastid Z ring formation. These alleles will facilitate understanding of how the in vitro biochemical properties of FtsZ1 are related to its in vivo function.
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Affiliation(s)
- David W Yoder
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
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Gremillon L, Kiessling J, Hause B, Decker EL, Reski R, Sarnighausen E. Filamentous temperature-sensitive Z (FtsZ) isoforms specifically interact in the chloroplasts and in the cytosol of Physcomitrella patens. New Phytol 2007; 176:299-310. [PMID: 17888112 DOI: 10.1111/j.1469-8137.2007.02169.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plant filamentous temperature-sensitive Z (FtsZ) proteins have been reported to be involved in biological processes related to plastids. However, the precise functions of distinct isoforms are still elusive. Here, the intracellular localization of the FtsZ1-1 isoform in a moss, Physcomitrella patens, was examined. Furthermore, the in vivo interaction behaviour of four distinct FtsZ isoforms was investigated. Localization studies of green fluorescent protein (GFP)-tagged FtsZ1-1 and fluorescence resonance energy transfer (FRET) analyses employing all dual combinations of four FtsZ isoforms were performed in transient protoplast transformation assays. FtsZ1-1 is localized to network structures inside the chloroplasts and exerts influence on plastid division. Interactions between FtsZ isoforms occur in distinct ordered structures in the chloroplasts as well as in the cytosol. The results expand the view of the involvement of Physcomitrella FtsZ proteins in chloroplast and cell division. It is concluded that duplication and diversification of ftsZ genes during plant evolution were the main prerequisites for the successful remodelling and integration of the prokaryotic FtsZ-dependent division mechanism into the cellular machineries of distinct complex processes in plants.
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Affiliation(s)
- Louis Gremillon
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany
| | - Justine Kiessling
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany
| | - Bettina Hause
- Leibniz Institute of Plant Biochemistry, Department of Secondary Metabolism, Weinberg 3, 06120 Halle/Saale, Germany
| | - Eva L Decker
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany
| | - Eric Sarnighausen
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany
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8
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Osawa M, Erickson HP. FtsZ from divergent foreign bacteria can function for cell division in Escherichia coli. J Bacteriol 2006; 188:7132-40. [PMID: 17015652 PMCID: PMC1636228 DOI: 10.1128/jb.00647-06] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Accepted: 08/01/2006] [Indexed: 11/20/2022] Open
Abstract
FtsZs from Mycoplasma pulmonis (MpuFtsZ) and Bacillus subtilis (BsFtsZ) are only 46% and 53% identical in amino acid sequence to FtsZ from Escherichia coli (EcFtsZ). In the present study we show that MpuFtsZ and BsFtsZ can function for cell division in E. coli provided we make two modifications. First, we replaced their C-terminal tails with that from E. coli, giving the foreign FtsZ the binding site for E. coli FtsA and ZipA. Second, we selected for mutations in the E. coli genome that facilitated division by the foreign FtsZs. These suppressor strains arose at a relatively high frequency of 10(-3) to 10(-5), suggesting that they involve loss-of-function mutations in multigene pathways. These pathways may be negative regulators of FtsZ or structural pathways that facilitate division by slightly defective FtsZ. Related suppressor strains were obtained for EcFtsZ containing certain point mutations or insertions of yellow fluorescent protein. The ability of highly divergent FtsZs to function for division in E. coli is consistent with a two-part mechanism. FtsZ assembles the Z ring, and perhaps generates the constriction force, through self interactions; the downstream division proteins remodel the peptidoglycan wall by interacting with each other and the wall. The C-terminal peptide of FtsZ, which binds FtsA, provides the link between FtsZ assembly and peptidoglycan remodeling.
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Affiliation(s)
- Masaki Osawa
- Department Cell Biology, Box 3709, Duke University Medical Center, Durham, NC 27710, USA
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Lohse S, Hause B, Hause G, Fester T. FtsZ characterization and immunolocalization in the two phases of plastid reorganization in arbuscular mycorrhizal roots of Medicago truncatula. Plant Cell Physiol 2006; 47:1124-34. [PMID: 16854943 DOI: 10.1093/pcp/pcj083] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We have analyzed plastid proliferation in root cortical cells of Medicago truncatula colonized by arbuscular mycorrhizal (AM) fungi by concomitantly labeling fungal structures, root plastids, a protein involved in plastid division (FtsZ1) and a protein involved in the biosynthesis of AM-specific apocarotenoids. Antibodies directed against FtsZ1 have been generated after heterologous expression of the respective gene from M. truncatula and characterization of the gene product. Analysis of enzymatic activity and assembly experiments showed similar properties of this protein when compared with the bacterial proteins. Immunocytological experiments allowed two phases of fungal and plastid development to be clearly differentiated and plastid division to be monitored during these phases. In the early phase of arbuscule development, lens-shaped plastids, intermingled with the arbuscular branches, divide frequently. Arbuscule degradation, in contrast, is characterized by large, tubular plastids, decorated by a considerable number of FtsZ division rings.
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Affiliation(s)
- Swanhild Lohse
- Leibniz Institute of Plant Biochemistry, Department of Secondary Metabolism, Weinberg 3, D-06120 Halle (Saale), Germany
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10
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Tavva VS, Collins GB, Dinkins RD. Targeted overexpression of the Escherichia coli MinC protein in higher plants results in abnormal chloroplasts. Plant Cell Rep 2006; 25:341-8. [PMID: 16341725 DOI: 10.1007/s00299-005-0086-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Revised: 10/17/2005] [Accepted: 10/26/2005] [Indexed: 05/05/2023]
Abstract
Higher plant chloroplast division involves some of the same types of proteins that are required in prokaryotic cell division. These include two of the three Min proteins, MinD and MinE, encoded by the min operon in bacteria. Noticeably absent from annotated sequences from higher plants is a MinC homologue. A higher plant functional MinC homologue that would interfere with FtsZ polymerization, has yet to be identified. We sought to determine whether expression of the bacterial MinC in higher plants could affect chloroplast division. The Escherichia coli minC (EcMinC) gene was isolated and inserted behind the Arabidopsis thaliana RbcS transit peptide sequence for chloroplast targeting. This TP-EcMinC gene driven by the CaMV 35S(2) constitutive promoter was then transformed into tobacco (Nicotiana tabacum L.). Abnormally large chloroplasts were observed in the transgenic plants suggesting that overexpression of the E. coli MinC perturbed higher plant chloroplast division.
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Affiliation(s)
- Venkata S Tavva
- Department of Plant and Soil Sciences, University of Kentucky, 1405 Veterans Road, Lexington, KY 40546-0312, USA
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El-Kafafi ES, Mukherjee S, El-Shami M, Putaux JL, Block M, Pignot-Paintrand I, Lerbs-Mache S, Falconet D. The plastid division proteins, FtsZ1 and FtsZ2, differ in their biochemical properties and sub-plastidial localization. Biochem J 2005; 387:669-76. [PMID: 15601251 PMCID: PMC1134996 DOI: 10.1042/bj20041281] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Revised: 12/06/2004] [Accepted: 12/14/2004] [Indexed: 11/17/2022]
Abstract
Plastid division in higher plants is morphologically similar to bacterial cell division, with a process termed binary fission involving constriction of the envelope membranes. FtsZ proteins involved in bacterial division are also present in higher plants, in which the ftsZ genes belong to two distinct families: ftsZ1 and ftsZ2. However, the roles of the corresponding proteins FtsZ1 and FtsZ2 in plastid division have not been determined. Here we show that the expression of plant FtsZ1 and FtsZ2 in bacteria has different effects on cell division, and that distinct protein domains are involved in the process. We have studied the assembly of purified FtsZ1 and FtsZ2 using a chemical cross-linking approach followed by PAGE and electron microscopy analyses of the resulting polymers. This has revealed that FtsZ1 is capable of forming long rod-shaped polymers and rings similar to the bacterial FtsZ structures, whereas FtsZ2 does not form any organized polymer. Moreover, using purified sub-plastidial fractions, we show that both proteins are present in the stroma, and that a subset of FtsZ2 is tightly bound to the purified envelope membranes. These results indicate that FtsZ2 has a localization pattern distinct from that of FtsZ1, which can be related to distinct properties of the proteins. From the results presented here, we propose a model for the sequential topological localization and functions of green plant FtsZ1 and FtsZ2 in chloroplast division.
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Affiliation(s)
- El-Sayed El-Kafafi
- *Laboratoire de Génétique Moléculaire des Plantes, UMR 5575, CNRS-Université Joseph Fourier, BP 53, 38041 Grenoble, Cedex, France
| | - Sunil Mukherjee
- *Laboratoire de Génétique Moléculaire des Plantes, UMR 5575, CNRS-Université Joseph Fourier, BP 53, 38041 Grenoble, Cedex, France
| | - Mahmoud El-Shami
- *Laboratoire de Génétique Moléculaire des Plantes, UMR 5575, CNRS-Université Joseph Fourier, BP 53, 38041 Grenoble, Cedex, France
| | - Jean-Luc Putaux
- †Centre de Recherches sur les Macromolécules Végétales (affiliated with the Université Joseph Fourier), UPR 5301-CNRS, BP 53, F-38041 Grenoble Cedex 9, France
| | - Maryse A. Block
- ‡Laboratoire de Physiologie Cellulaire Végétale, UMR 5168 CNRS–CEA–Université Joseph Fourier–INRA, CEA-Grenoble, DRDC-PCV, 17 rue des martyrs, 38054 Grenoble Cedex, France
| | - Isabelle Pignot-Paintrand
- †Centre de Recherches sur les Macromolécules Végétales (affiliated with the Université Joseph Fourier), UPR 5301-CNRS, BP 53, F-38041 Grenoble Cedex 9, France
| | - Silva Lerbs-Mache
- *Laboratoire de Génétique Moléculaire des Plantes, UMR 5575, CNRS-Université Joseph Fourier, BP 53, 38041 Grenoble, Cedex, France
| | - Denis Falconet
- *Laboratoire de Génétique Moléculaire des Plantes, UMR 5575, CNRS-Université Joseph Fourier, BP 53, 38041 Grenoble, Cedex, France
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Abstract
The plastid division proteins FtsZ are encoded by a small nuclear gene family in land plants. Although it has been shown for some of the gene products that they are imported into plastids and function in plastid division, the evolution and function of this gene family and their products remain to be unraveled. Here we present two new ftsZ genes from the moss Physcomitrella patens and compare the genomic structure of members of the two plant ftsZ gene families. Comparison of sequence features and phylogenetic analyses confirm the presence of two clusters of paralogues in land plants and demonstrate that these genes were duplicated before the divergence of mosses, ferns and seed plants.
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Affiliation(s)
- Stefan A Rensing
- University of Freiburg, Plant Biotechnology, Sonnenstr. 5, D-79104 Freiburg, Germany,
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13
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Abstract
Homologues of the bacterial cell division protein FtsZ are found in higher plants where they function as key components of the chloroplast division complex. In contrast to most bacteria that encode a single FtsZ protein, plants encode multiple proteins that group into two families, FtsZ1 and FtsZ2. Using new sequence data from a broad range photosynthetic organisms, we performed a series of analyses to better understand the evolutionary history of the plant FtsZ families. Multiple phylogenetic analyses strongly support the grouping of the plant FtsZ genes and proteins into distinct FtsZ1 and FtsZ2 clades. Protein features representing potentially significant functional differences between FtsZ1 and FtsZ2 are identified. Genomic structure comparisons show that exon length and intron position are conserved within each clade, but differ between the clades except at one position. Our data indicate that the divergence of the FtsZ1 and FtsZ2 families occurred long before the evolution of land plants, preceding the emergence of the green algae. The results are consistent with proposals that the two FtsZ families evolved distinct functions during evolution of the chloroplast division apparatus, and indicate that genetic and functional differentiation occurred much earlier than previously hypothesized.
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Affiliation(s)
- Kevin D Stokes
- Department of Plant Biology, Michigan State University, 166 Plant Biology Building, East Lansing, MI 48824-1312, USA
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Abstract
Mitochondria and chloroplasts are essential eukaryotic organelles of endosymbiotic origin. Dynamic cellular machineries divide these organelles. The mechanisms by which mitochondria and chloroplasts divide were thought to be fundamentally different because chloroplasts use proteins derived from the ancestral prokaryotic cell division machinery, whereas mitochondria have largely evolved a division apparatus that lacks bacterial cell division components. Recent findings indicate, however, that both types of organelles universally require dynamin-related guanosine triphosphatases to divide. This mechanistic link provides fundamental insights into the molecular events driving the division, and possibly the evolution, of organelles in eukaryotes.
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Affiliation(s)
- Katherine W Osteryoung
- Department of Plant Biology, 166 Plant Biology Building, Michigan State University, East Lansing, MI 48824, USA.
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15
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Abstract
After the beginning of the recombinant DNA era in the mid-1970s, researchers in India started to make use of the new technology to understand the structure of plant genes and regulation of their expression. The outcome started to appear in print in early the 1980s and genes for histones, tubulin, photosynthetic membrane proteins, phototransduction components, organelles and those regulated differentially by developmental and extrinsic signals were sequenced and characterized. Some genes of biotechnological importance like those encoding an interesting seed protein and the enzyme glyoxalase were also isolated. While work on the characterization of genome structure and organization was started quite early, it remained largely focused on the identification of DNA markers and genetic variability. In this context, the work on mustard, rice and wheat is worth mentioning. In the year 2000, India became a member of the international consortium to sequence entire rice genome. Several laboratories have also given attention to regulated expression of plastid and nuclear genes as well as to isolate target-specific promoters or design promoters with improved potential. Simultaneously, transgenic systems for crops like mustard, rice, wheat, cotton, legumes and several vegetables have been established. More recently, genes of agronomic importance like those for insect resistance, abiotic stress tolerance, nutritional improvement and male sterility, isolated in India or abroad, have been utilized for raising transgenics for crop improvement. Some of these transgenics have already shown their potential in containment facility or limited field trials conducted under the stipulated guidelines. Plant molecular biology and biotechnology are thus clearly poised to make an impact on research in basic biology and agriculture in the near future.
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Affiliation(s)
- Akhilesh K Tyagi
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India.
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16
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Abstract
Photosynthetic eukaryotes have evolved plastid division mechanisms since acquisition of plastids through endosymbiosis. The emerging evolutionary origin of the plastid division mechanism is remarkably complex. The constituents of the division apparatus of plastids may have complex origins. The one constituent is the plastid FtsZ ring taken over from the cyanobacteria-like ancestral endosymbionts. The second is the doublet of concentric plastid dividing rings (or triplet in red algae), possibly acquired by ancestral host eukaryotes following the primary endosymbiotic event. Placement of the division apparatus at the correct division site may involve a system analogous to the bacterial Min system. Plastid nucleoid partitioning may be mediated by binding to envelope or thylakoid membranes. Multiple copies of plastid DNA and symmetrical distribution of the nucleoids in the plastids may permit faithful transmission to daughter plastids via equal binary plastid divisions. Cyanelles retain peptidoglycan wall and cyanelle division occurs through septum formation such as bacterial cell division. Cyanelle division involves the cyanelle ring analogous to the inner stromal plastid-dividing (PD) ring. According to the prevailing hypothesis that primary endosymbiosis occurred only once, cyanelle division may represent an intermediate stage between cyanobacterial division and the well-known plastid division among extant plants. With the secondary plastids, which are surrounded by three or four membranes, the PD ring also participates in division of the inner two "true" plastid envelope membranes, and the third and the outermost membranes divide by unknown mechanisms.
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Affiliation(s)
- Haruki Hashimoto
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
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18
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Dziadek J, Madiraju MVVS, Rutherford SA, Atkinson MAL, Rajagopalan M. Physiological consequences associated with overproduction of Mycobacterium tuberculosis FtsZ in mycobacterial hosts. Microbiology (Reading) 2002; 148:961-971. [PMID: 11932443 DOI: 10.1099/00221287-148-4-961] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The ftsZ gene of Mycobacterium tuberculosis H37Rv has been characterized as the first step in determining the molecular events involved in the cell division process in mycobacteria. Western analysis revealed that intracellular levels of FtsZ are growth phase dependent in both M. tuberculosis and Mycobacterium smegmatis. Unregulated expression of M. tuberculosis ftsZ from constitutive hsp60 and dnaA promoters in M. tuberculosis hosts resulted in lethality whereas expression from only the hsp60 promoter was toxic in M. smegmatis hosts. Expression of ftsZ from the dnaA promoter in M. smegmatis resulted in approximately sixfold overproduction and the merodiploids exhibited slow growth, an increased tendency to clump and filament, and in some cases produced buds and branches. Many of the cells also contained abnormal and multiple septa. Expression of ftsZ from the chemically inducible acetamidase promoter in M. smegmatis hosts resulted in approximately 22-fold overproduction of FtsZ and produced filamentous cells, many of which lacked any visible septa. Visualization of the M. tuberculosis FtsZ tagged with green fluorescent protein in M. smegmatis by fluorescence microscopy revealed multiple fluorescent FtsZ foci, suggesting that steps subsequent to the formation of organized FtsZ structures but prior to septum formation are blocked in FtsZ-overproducing cells. Together these results suggest that the intracellular concentration of FtsZ protein is critical for productive septum formation in mycobacteria.
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Affiliation(s)
- Jaroslaw Dziadek
- Biomedical Research, The University of Texas Health Center at Tyler, 11937 US Hwy @ 271, Tyler, TX-75708-3154, USA1
| | - Murty V V S Madiraju
- Biomedical Research, The University of Texas Health Center at Tyler, 11937 US Hwy @ 271, Tyler, TX-75708-3154, USA1
| | - Stacey A Rutherford
- Biomedical Research, The University of Texas Health Center at Tyler, 11937 US Hwy @ 271, Tyler, TX-75708-3154, USA1
| | - Mark A L Atkinson
- Biomedical Research, The University of Texas Health Center at Tyler, 11937 US Hwy @ 271, Tyler, TX-75708-3154, USA1
| | - Malini Rajagopalan
- Biomedical Research, The University of Texas Health Center at Tyler, 11937 US Hwy @ 271, Tyler, TX-75708-3154, USA1
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McAndrew RS, Froehlich JE, Vitha S, Stokes KD, Osteryoung KW. Colocalization of plastid division proteins in the chloroplast stromal compartment establishes a new functional relationship between FtsZ1 and FtsZ2 in higher plants. Plant Physiol 2001; 127:1656-1666. [PMID: 11743110 DOI: 10.1104/pp.010542] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Chloroplast division is driven by a macromolecular complex containing components that are positioned on the cytosolic surface of the outer envelope, the stromal surface of the inner envelope, and in the intermembrane space. The only constituents of the division apparatus identified thus far are the tubulin-like proteins FtsZ1 and FtsZ2, which colocalize to rings at the plastid division site. However, the precise positioning of these rings relative to the envelope membranes and to each other has not been previously defined. Using newly isolated cDNAs with open reading frames longer than those reported previously, we demonstrate here that both FtsZ2 proteins in Arabidopsis, like FtsZ1 proteins, contain cleavable transit peptides that target them across the outer envelope membrane. To determine their topological arrangement, protease protection experiments designed to distinguish between stromal and intermembrane space localization were performed on both in vitro imported and endogenous forms of FtsZ1 and FtsZ2. Both proteins were shown to reside in the stromal compartment of the chloroplast, indicating that the FtsZ1- and FtsZ2-containing rings have similar topologies and may physically interact. Consistent with this hypothesis, double immunofluorescence labeling of various plastid division mutants revealed precise colocalization of FtsZ1 and FtsZ2, even when their levels and assembly patterns were perturbed. Overexpression of FtsZ2 in transgenic Arabidopsis inhibited plastid division in a dose-dependent manner, suggesting that the stoichiometry between FtsZ1 and FtsZ2 is an important aspect of their function. These studies raise new questions concerning the functional and evolutionary significance of two distinct but colocalized forms of FtsZ in plants and establish a revised framework within which to understand the molecular architecture of the plastid division apparatus in higher plants.
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Affiliation(s)
- R S McAndrew
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824, USA
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20
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Abstract
Plant nuclear genomes encode chloroplast division proteins homologous to the eubacterial cell division protein FtsZ. In higher plants, FtsZ genes constitute a small gene family that consists of two subgroups, FtsZ1 and FtsZ2. It was previously hypothesized that members of one family (FtsZ1) targeted chloroplasts, while members of the other family (FtsZ2) localized in the cytoplasm. We determined the full-length cDNA sequences of two FtsZ2 genes from Arabidopsis thaliana (AtFtsZ2-1 and AtFtsZ2-2) and found that the genes encode polypeptides of 478 and 473 amino acids, respectively, and both contain N-terminal extensions beyond what have previously been predicted. The N-terminal regions of both AtFtsZ2-1 and AtFtsZ2-2 were expressed as green fluorescent protein (GFP) fusions under the cauliflower mosaic virus 35S promoter in bombarded tobacco cells. Confocal laser scanning microscopy revealed both fusions exclusively localized to chloroplasts, demonstrating that the N-terminal regions function as chloroplast-targeting signals in vivo. Thus, FtsZ2 proteins function within chloroplasts.
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Affiliation(s)
- M Fujiwara
- Plant Functions Laboratory, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198, Japan.
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21
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Abstract
Plastid division is essential for the maintenance of plastid populations in cells undergoing division and for the accumulation of large chloroplast numbers in photosynthetic tissues. Although the mechanisms mediating plastid division are poorly understood, ultrastructural studies imply this process is accomplished by a dynamic macromolecular machine organized into ring structures at the plastid midpoint. A key component of the engine that powers this machine is the motor-like protein FtsZ, a cytoskeletal GTPase of endosymbiotic origin that forms a ring at the plastid division site, similar to the function of its prokaryotic relatives in bacterial cytokinesis. This review considers the phylogenetic distribution and structural properties of two recently identified plant FtsZ protein families in the context of their distinct roles in plastid division and describes current evidence regarding factors that govern their placement at the division site. Because of their evolutionary and mechanistic relationship, the process of bacterial cell division provides a valuable, though incomplete, paradigm for understanding plastid division in plants.
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Affiliation(s)
- Katherine W Osteryoung
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824; e-mail: ,
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22
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Mori T, Kuroiwa H, Takahara M, Miyagishima SY, Kuroiwa T. Visualization of an FtsZ ring in chloroplasts of Lilium longiflorum leaves. Plant Cell Physiol 2001; 42:555-559. [PMID: 11427673 DOI: 10.1093/pcp/pce095] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
FtsZ is a bacterial division protein which forms a ring at the leading edge of the cell division site. To date, a hypothesis that the plant FtsZ forms the same structure in chloroplast division is proposed, but has not been demonstrated yet. In this study, recombinant LlFtsZ (Lilium longiflorum FtsZ) protein was produced from a previously isolated ftsZ cDNA clone [Mori and Tanaka (2000) Protoplasma 214: 57] and used to raise polyclonal anti-LlFtsZ antibodies in rabbits. In immunoblot analysis with the total protein extracted from L. longiflorum leaves, purified antibodies specifically recognized LlFtsZ whose molecular mass was approximately 43 kDa. This size corresponded to that of the recombinant LlFtsZ protein lacking N-terminal sequence, which suggests that the full-length LlFtsZ translation product has a putative N-terminal signal peptide. Moreover, fluorescent and electron microscopy revealed that the anti-LlFtsZ antibodies recognized ring structures at stromal side of the constriction point of dividing chloroplasts. Here, we show direct evidence that FtsZ ring is involved in chloroplast division.
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Affiliation(s)
- T Mori
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Tokyo, 113-0033 Japan.
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23
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Abstract
Among the events that accompanied the evolution of chloroplasts from their endosymbiotic ancestors was the host cell recruitment of the prokaryotic cell division protein FtsZ to function in chloroplast division. FtsZ, a structural homologue of tubulin, mediates cell division in bacteria by assembling into a ring at the midcell division site. In higher plants, two nuclear-encoded forms of FtsZ, FtsZ1 and FtsZ2, play essential and functionally distinct roles in chloroplast division, but whether this involves ring formation at the division site has not been determined previously. Using immunofluorescence microscopy and expression of green fluorescent protein fusion proteins in Arabidopsis thaliana, we demonstrate here that FtsZ1 and FtsZ2 localize to coaligned rings at the chloroplast midpoint. Antibodies specific for recognition of FtsZ1 or FtsZ2 proteins in Arabidopsis also recognize related polypeptides and detect midplastid rings in pea and tobacco, suggesting that midplastid ring formation by FtsZ1 and FtsZ2 is universal among flowering plants. Perturbation in the level of either protein in transgenic plants is accompanied by plastid division defects and assembly of FtsZ1 and FtsZ2 into filaments and filament networks not observed in wild-type, suggesting that previously described FtsZ-containing cytoskeletal-like networks in chloroplasts may be artifacts of FtsZ overexpression.
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Affiliation(s)
- Stanislav Vitha
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Rosemary S. McAndrew
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
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Ramirez-Arcos S, Szeto J, Beveridge T, Victor C, Francis F, Dillon J. Deletion of the cell-division inhibitor MinC results in lysis of Neisseria gonorrhoeae. Microbiology (Reading) 2001; 147:225-37. [PMID: 11160816 DOI: 10.1099/00221287-147-1-225] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The minCDE genes involved in division site selection in Neisseria gonorrhoeae were identified using raw data from the N. gonorrhoeae genome project and are part of a cluster of 27 genes. When gonococcal min genes were heterologously expressed as a cluster in Escherichia coli, minicells and filaments were produced, indicating that gonococcal min genes disrupted cell division in other genera. The insertional inactivation of the minC gene of N. gonorrhoeae CH811 resulted in a strain (CSRC1) with decreased viability and grossly abnormal cell division as observed by phase-contrast and electron microscopy analysis. Western blot analysis of N. gonorrhoeae CSRC1 confirmed that MinC(Ng) was not produced. Complementation of CSRC1 by integrating a minC-6xHis tag fusion at the proAB locus by homologous recombination restored viability and 1.9 times wild-type levels of MinC(Ng) expression. This slight increase of expression caused a small percentage of the complemented cells to divide aberrantly. This suggested that the 6xHis tag has partially affected the stability of MinC, or that the chromosomal position of minC is critical to its regulation. Comparison of MinC proteins from different bacteria showed a homologous region corresponding to residues 135-230 with five conserved amino acids. Overexpression of MinC(Ng) in wild-type E. coli cells induced filamentation and an E. coli minC mutant was successfully complemented with minC(Ng). Therefore, the evidence indicates that MinC from N. gonorrhoeae acts as a cell-division inhibitor and that its role is essential in maintaining proper division in cocci.
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Affiliation(s)
- S Ramirez-Arcos
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
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Stokes KD, McAndrew RS, Figueroa R, Vitha S, Osteryoung KW. Chloroplast division and morphology are differentially affected by overexpression of FtsZ1 and FtsZ2 genes in Arabidopsis. Plant Physiol 2000; 124:1668-77. [PMID: 11115884 PMCID: PMC59865 DOI: 10.1104/pp.124.4.1668] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2000] [Revised: 09/16/2000] [Accepted: 09/20/2000] [Indexed: 05/20/2023]
Abstract
In higher plants, two nuclear gene families, FtsZ1 and FtsZ2, encode homologs of the bacterial protein FtsZ, a key component of the prokaryotic cell division machinery. We previously demonstrated that members of both gene families are essential for plastid division, but are functionally distinct. To further explore differences between FtsZ1 and FtsZ2 proteins we investigated the phenotypes of transgenic plants overexpressing AtFtsZ1-1 or AtFtsZ2-1, Arabidopsis members of the FtsZ1 and FtsZ2 families, respectively. Increasing the level of AtFtsZ1-1 protein as little as 3-fold inhibited chloroplast division. Plants with the most severe plastid division defects had 13- to 26-fold increases in AtFtsZ1-1 levels over wild type, and some of these also exhibited a novel chloroplast morphology. Quantitative immunoblotting revealed a correlation between the degree of plastid division inhibition and the extent to which the AtFtsZ1-1 protein level was elevated. In contrast, expression of an AtFtsZ2-1 sense transgene had no obvious effect on plastid division or morphology, though AtFtsZ2-1 protein levels were elevated only slightly over wild-type levels. This may indicate that AtFtsZ2-1 accumulation is more tightly regulated than that of AtFtsZ1-1. Plants expressing the AtFtsZ2-1 transgene did accumulate a form of the protein smaller than those detected in wild-type plants. AtFtsZ2-1 levels were unaffected by increased or decreased accumulation of AtFtsZ1-1 and vice versa, suggesting that the levels of these two plastid division proteins are regulated independently. Taken together, our results provide additional evidence for the functional divergence of the FtsZ1 and FtsZ2 plant gene families.
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Affiliation(s)
- K D Stokes
- Department of Botany and Plant Pathology, 166 Plant Biology Building, Michigan State University, East Lansing, Michigan 48824-1312, USA
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Kanamaru K, Fujiwara M, Kim M, Nagashima A, Nakazato E, Tanaka K, Takahashi H. Chloroplast targeting, distribution and transcriptional fluctuation of AtMinD1, a Eubacteria-type factor critical for chloroplast division. Plant Cell Physiol 2000; 41:1119-28. [PMID: 11148270 DOI: 10.1093/pcp/pcd037] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In Arabidopsis thaliana, a mature mesophyll cell contains approximately 100 chloroplasts. Although 12 arc mutants (accumulation and replication of chloroplasts) and two chloroplast division genes homologous to eubacterial ftsZ have been isolated from A. thaliana, the molecular mechanism underlying the chloroplast division is still unclear. We characterized AtMinD1, a eubacterial minD homolog, for chloroplast division in A. thaliana. AtMinD1-green fluorescent protein targeted to the chloroplasts and possibly associated with the envelope membranes in vivo. During the seed germination, the AtMinD1 transcripts were accumulated twice, just after release from cold treatment and at the beginning of rapid greening, in similar fashion to AtFtsZs. Furthermore the transcript level in a severest chloroplast division mutant, arc6, was 3-5-fold higher than that in wild-type.
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Affiliation(s)
- K Kanamaru
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Japan
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