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Williams J, Regedanz E, Lucinda N, Nava Fereira AR, Lacatus G, Berger M, O’Connell N, Coursey T, Ruan J, Bisaro DM, Sunter G. Mutation of the conserved late element in geminivirus CP promoters abolishes Arabidopsis TCP24 transcription factor binding and decreases H3K27me3 levels on viral chromatin. PLoS Pathog 2024; 20:e1012399. [PMID: 39024402 PMCID: PMC11288445 DOI: 10.1371/journal.ppat.1012399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 07/30/2024] [Accepted: 07/07/2024] [Indexed: 07/20/2024] Open
Abstract
In geminiviruses belonging to the genus Begomovirus, coat protein (CP) expression depends on viral AL2 protein, which derepresses and activates the CP promoter through sequence elements that lie within the viral intergenic region (IR). However, AL2 does not exhibit sequence-specific DNA binding activity but is instead directed to responsive promoters through interactions with host factors, most likely transcriptional activators and/or repressors. In this study, we describe a repressive plant-specific transcription factor, Arabidopsis thaliana TCP24 (AtTCP24), that interacts with AL2 and recognizes a class II TCP binding site in the CP promoter (GTGGTCCC). This motif corresponds to the previously identified conserved late element (CLE). We also report that histone 3 lysine 27 trimethylation (H3K27me3), an epigenetic mark associated with facultative repression, is enriched over the viral IR. H3K27me3 is deposited by Polycomb Repressive Complex 2 (PRC2), a critical regulator of gene expression and development in plants and animals. Remarkably, mutation of the TCP24 binding site (the CLE) in tomato golden mosaic virus (TGMV) and cabbage leaf curl virus (CaLCuV) CP promoters greatly diminishes H3K27me3 levels on viral chromatin and causes a dramatic delay and attenuation of disease symptoms in infected Arabidopsis and Nicotiana benthamiana plants. Symptom remission is accompanied by decreased viral DNA levels in systemically infected tissue. Nevertheless, in transient replication assays CLE mutation delays but does not limit the accumulation of viral double-stranded DNA, although single-stranded DNA and CP mRNA levels are decreased. These findings suggest that TCP24 binding to the CLE leads to CP promoter repression and H3K27me3 deposition, while TCP24-AL2 interaction may recruit AL2 to derepress and activate the promoter. Thus, a repressive host transcription factor may be repurposed to target a viral factor essential for promoter activity. The presence of the CLE in many begomoviruses suggests a common scheme for late promoter regulation.
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Affiliation(s)
- Jacqueline Williams
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Elizabeth Regedanz
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, and Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, United States of America
| | - Natalia Lucinda
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, United States of America
| | - Alba Ruth Nava Fereira
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, United States of America
| | - Gabriela Lacatus
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Mary Berger
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Nels O’Connell
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, and Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, United States of America
| | - Tami Coursey
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, and Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, United States of America
| | - Jianhua Ruan
- Department of Computer Science, The University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - David M. Bisaro
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, and Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, United States of America
| | - Garry Sunter
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, United States of America
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, United States of America
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Sun PP, Zhang L, Xu XZ, Zhu M, Zhang B, Li ZN. Molecular Characterization of Three Apple Geminivirus Isolates in Crabapples Detected in Inner Mongolia, China. PLANTS (BASEL, SWITZERLAND) 2023; 12:195. [PMID: 36616324 PMCID: PMC9824349 DOI: 10.3390/plants12010195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
Apple geminivirus 1 (AGV) in the genus Maldovirus of the family Geminiviridae was first identified infecting apple trees in the year 2015 in China. In this work, we characterized three isolates of the AGV in the Chinese pearleaf crabapple (Malus asiatica) in Inner Mongolia Autonomous Region. The viruses were detected by Illumina sequencing and its existence was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) amplification of an AGV fragment. Between the three AGV isolates and the initially characterized AGV isolate PL2015, the nucleotide sequence identities of the complete genome ranged from 91.2 to 91.7%, of the coat protein gene (V1) ranged from 95.4% to 97.3%, and of the replicase gene (C1) ranged from 87.3% to 88.0%. Phylogenetic analysis indicated that the three isolates formed a monophyletic group together with the AGV, separated from the current genera in the family Geminiviridae. This is the first description of the AGV infecting crabapples.
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Affiliation(s)
- Ping-Ping Sun
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Lei Zhang
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Xiao-Zhao Xu
- College of Horticulture, Qingdao Agricultural University, Qingdao 266109, China
| | - Mo Zhu
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Bin Zhang
- College of Life Sciences & Technology, Inner Mongolia Normal University, Hohhot 010028, China
| | - Zheng-Nan Li
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot 010018, China
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An JW, Lee JH, Choi S, Venkatesh J, Kim JM, Kwon JK, Kang BC. Identification of the determinant of tomato yellow leaf curl Kanchanaburi virus infectivity in tomato. Virus Res 2021; 291:198192. [PMID: 33058965 DOI: 10.1016/j.virusres.2020.198192] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/24/2020] [Accepted: 10/06/2020] [Indexed: 12/20/2022]
Abstract
Geminiviruses cause devastating diseases in solanaceous crops, with the bipartite begomoviruses tomato yellow leaf curl Kanchanaburi virus (TYLCKaV) and pepper yellow leaf curl Thailand virus (PYLCThV) major threats in Southeast Asia. To determine the molecular mechanism of geminivirus infection, we constructed infectious clones of TYLCKaV and PYLCThV. Both constructs infected Nicotiana benthamiana, but only TYLCKaV could infect Solanum lycopersicum 'A39'. A genome-swapping of TYLCKaV with PYLCThV revealed the TYLCKaV-B genome segment as the determinant of TYLCKaV infectivity in tomato. We constructed five geminivirus clones with chimeric TYLCKaV-B and PYLCThV-B genome segments to narrow down the region determining TYLCKaV infectivity in tomato. Only chimeric clones carrying the TYLCKaV intergenic region (IR) showed infectivity in S. lycopersicum 'A39', indicating that the IR of TYLCKaV-B is essential for TYLCKaV infectivity in tomato. Our results provide a foundation for elucidating the molecular mechanism of geminivirus infection in plants.
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Affiliation(s)
- Jong-Wook An
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Joung-Ho Lee
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Seula Choi
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jelli Venkatesh
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jung-Min Kim
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jin-Kyung Kwon
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Byoung-Cheorl Kang
- Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
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Wang YM, He YZ, Ye XT, He WZ, Liu SS, Wang XW. Whitefly HES1 binds to the intergenic region of Tomato yellow leaf curl China virus and promotes viral gene transcription. Virology 2020; 542:54-62. [PMID: 32056668 PMCID: PMC7031692 DOI: 10.1016/j.virol.2020.01.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/15/2020] [Accepted: 01/18/2020] [Indexed: 01/02/2023]
Abstract
Intergenic region of begomovirus genome is vital to virus replication and viral gene transcription in plants. Previous studies have reported that Tomato yellow leaf curl China virus (TYLCCNV), a begomovirus, is able to accumulate and transcribe in its whitefly vector. However, the viral and host components that participate in begomovirus transcription in whiteflies are hitherto unknown. Using a yeast one-hybrid system, we identified >50 whitefly proteins that interacted with TYLCCNV intergenic region. Dual luciferase analysis revealed that one of the identified proteins, the hairy and enhancer of split homolog-1 (HES1), specifically bound to CACGTG motif in TYLCCNV intergenic region. Silencing HES1 decreased viral transcription, accumulation and transmission. These results demonstrate that the interactions between whitefly proteins and the intergenic region of TYLCCNV may contribute to viral transcription in the whitefly vector. Our findings offer valuable clues for the research and development of novel strategies to interfere with begomovirus transmission.
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Affiliation(s)
- Yu-Meng Wang
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crops Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Ya-Zhou He
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crops Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Xin-Tong Ye
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crops Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Wen-Ze He
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crops Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Shu-Sheng Liu
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crops Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Xiao-Wei Wang
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crops Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China.
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Borah B, Zarreen F, Baruah G, Dasgupta I. Insights into the control of geminiviral promoters. Virology 2016; 495:101-11. [DOI: 10.1016/j.virol.2016.04.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 10/21/2022]
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Cominelli E, Galbiati M, Albertini A, Fornara F, Conti L, Coupland G, Tonelli C. DOF-binding sites additively contribute to guard cell-specificity of AtMYB60 promoter. BMC PLANT BIOLOGY 2011; 11:162. [PMID: 22088138 PMCID: PMC3248575 DOI: 10.1186/1471-2229-11-162] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 11/16/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND We previously demonstrated that the Arabidopsis thaliana AtMYB60 protein is an R2R3MYB transcription factor required for stomatal opening. AtMYB60 is specifically expressed in guard cells and down-regulated at the transcriptional levels by the phytohormone ABA. RESULTS To investigate the molecular mechanisms governing AtMYB60 expression, its promoter was dissected through deletion and mutagenesis analyses. By studying different versions of AtMYB60 promoter::GUS reporter fusions in transgenic plants we were able to demonstrate a modular organization for the AtMYB60 promoter. Particularly we defined: a minimal promoter sufficient to confer guard cell-specific activity to the reporter gene; the distinct roles of different DOF-binding sites organised in a cluster in the minimal promoter in determining guard cell-specific expression; the promoter regions responsible for the enhancement of activity in guard cells; a promoter region responsible for the negative transcriptional regulation by ABA. Moreover from the analysis of single and multiple mutants we could rule out the involvement of a group of DOF proteins, known as CDFs, already characterised for their involvement in flowering time, in the regulation of AtMYB60 expression. CONCLUSIONS These findings shed light on the regulation of gene expression in guard cells and provide new promoter modules as useful tools for manipulating gene expression in guard cells, both for physiological studies and future biotechnological applications.
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Affiliation(s)
- Eleonora Cominelli
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milano, Italy
- Istituto di Biologia e Biotecnologia Agraria, CNR, Milano, Italy
| | - Massimo Galbiati
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milano, Italy
- Fondazione Filarete, Milano, Italy
| | - Alessandra Albertini
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milano, Italy
| | - Fabio Fornara
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Dipartimento di Biologia, Università degli Studi di Milano, Milano, Italy
| | - Lucio Conti
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milano, Italy
- Fondazione Filarete, Milano, Italy
| | - George Coupland
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Chiara Tonelli
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milano, Italy
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Tanzer FL, Shephard EG, Palmer KE, Burger M, Williamson AL, Rybicki EP. The porcine circovirus type 1 capsid gene promoter improves antigen expression and immunogenicity in a HIV-1 plasmid vaccine. Virol J 2011; 8:51. [PMID: 21299896 PMCID: PMC3041773 DOI: 10.1186/1743-422x-8-51] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 02/07/2011] [Indexed: 12/02/2022] Open
Abstract
Background One of the promising avenues for development of vaccines against Human immunodeficiency virus type 1 (HIV-1) and other human pathogens is the use of plasmid-based DNA vaccines. However, relatively large doses of plasmid must be injected for a relatively weak response. We investigated whether genome elements from Porcine circovirus type 1 (PCV-1), an apathogenic small ssDNA-containing virus, had useful expression-enhancing properties that could allow dose-sparing in a plasmid vaccine. Results The linearised PCV-1 genome inserted 5' of the CMV promoter in the well-characterised HIV-1 plasmid vaccine pTHgrttnC increased expression of the polyantigen up to 2-fold, and elicited 3-fold higher CTL responses in mice at 10-fold lower doses than unmodified pTHgrttnC. The PCV-1 capsid gene promoter (Pcap) alone was equally effective. Enhancing activity was traced to a putative composite host transcription factor binding site and a "Conserved Late Element" transcription-enhancing sequence previously unidentified in circoviruses. Conclusions We identified a novel PCV-1 genome-derived enhancer sequence that significantly increased antigen expression from plasmids in in vitro assays, and improved immunogenicity in mice of the HIV-1 subtype C vaccine plasmid, pTHgrttnC. This should allow significant dose sparing of, or increased responses to, this and other plasmid-based vaccines. We also report investigations of the potential of other circovirus-derived sequences to be similarly used.
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Affiliation(s)
- Fiona L Tanzer
- Department of Molecular and Cell Biology, Faculty of Science, University of Cape Town, Rondebosch, Cape Town, 7701 South Africa
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8
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Gregorio-Jorge J, Bernal-Alcocer A, Bañuelos-Hernández B, Alpuche-Solís ÁG, Hernández-Zepeda C, Moreno-Valenzuela O, Frías-Treviño G, Argüello-Astorga GR. Analysis of a new strain of Euphorbia mosaic virus with distinct replication specificity unveils a lineage of begomoviruses with short Rep sequences in the DNA-B intergenic region. Virol J 2010; 7:275. [PMID: 20958988 PMCID: PMC2974675 DOI: 10.1186/1743-422x-7-275] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 10/19/2010] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Euphorbia mosaic virus (EuMV) is a member of the SLCV clade, a lineage of New World begomoviruses that display distinctive features in their replication-associated protein (Rep) and virion-strand replication origin. The first entirely characterized EuMV isolate is native from Yucatan Peninsula, Mexico; subsequently, EuMV was detected in weeds and pepper plants from another region of Mexico, and partial DNA-A sequences revealed significant differences in their putative replication specificity determinants with respect to EuMV-YP. This study was aimed to investigate the replication compatibility between two EuMV isolates from the same country. RESULTS A new isolate of EuMV was obtained from pepper plants collected at Jalisco, Mexico. Full-length clones of both genomic components of EuMV-Jal were biolistically inoculated into plants of three different species, which developed symptoms indistinguishable from those induced by EuMV-YP. Pseudorecombination experiments with EuMV-Jal and EuMV-YP genomic components demonstrated that these viruses do not form infectious reassortants in Nicotiana benthamiana, presumably because of Rep-iteron incompatibility. Sequence analysis of the EuMV-Jal DNA-B intergenic region (IR) led to the unexpected discovery of a 35-nt-long sequence that is identical to a segment of the rep gene in the cognate viral DNA-A. Similar short rep sequences ranging from 35- to 51-nt in length were identified in all EuMV isolates and in three distinct viruses from South America related to EuMV. These short rep sequences in the DNA-B IR are positioned downstream to a ~160-nt non-coding domain highly similar to the CP promoter of begomoviruses belonging to the SLCV clade. CONCLUSIONS EuMV strains are not compatible in replication, indicating that this begomovirus species probably is not a replicating lineage in nature. The genomic analysis of EuMV-Jal led to the discovery of a subgroup of SLCV clade viruses that contain in the non-coding region of their DNA-B component, short rep gene sequences located downstream to a CP-promoter-like domain. This assemblage of DNA-A-related sequences within the DNA-B IR is reminiscent of polyomavirus microRNAs and could be involved in the posttranscriptional regulation of the cognate viral rep gene, an intriguing possibility that should be experimentally explored.
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Affiliation(s)
- Josefat Gregorio-Jorge
- Instituto Potosino de Investigación Científica y Tecnológica, A.C., Camino a la Presa San José, 78216 San Luís Potosí, SLP, México
| | - Artemiza Bernal-Alcocer
- Universidad Autónoma Agraria Antonio Narro. Departamento de Parasitología Agrícola. Bellavista, C.P. 25315, Saltillo, Coahuila, Mexico
| | - Bernardo Bañuelos-Hernández
- Instituto Potosino de Investigación Científica y Tecnológica, A.C., Camino a la Presa San José, 78216 San Luís Potosí, SLP, México
| | - Ángel G Alpuche-Solís
- Instituto Potosino de Investigación Científica y Tecnológica, A.C., Camino a la Presa San José, 78216 San Luís Potosí, SLP, México
| | | | | | - Gustavo Frías-Treviño
- Universidad Autónoma Agraria Antonio Narro. Departamento de Parasitología Agrícola. Bellavista, C.P. 25315, Saltillo, Coahuila, Mexico
| | - Gerardo R Argüello-Astorga
- Instituto Potosino de Investigación Científica y Tecnológica, A.C., Camino a la Presa San José, 78216 San Luís Potosí, SLP, México
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Cazzonelli CI, Velten J. In vivo characterization of plant promoter element interaction using synthetic promoters. Transgenic Res 2008; 17:437-57. [PMID: 17653610 DOI: 10.1007/s11248-007-9117-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Accepted: 06/10/2007] [Indexed: 10/23/2022]
Abstract
Short directly-repeated (DR) DNA enhancer elements of plant viral origin were analyzed for their ability, both individually and in combination, to influence in vivo transcription when inserted upstream from a minimal CaMV35S promoter. Synthetic promoters containing multiple copies and/or combinations of DR cassettes were tested for their effect upon reporter gene (luciferase) expression using an Agrobacteria-based leaf-infiltration transient assay and within stably transformed plants (Nicotiana tabacum). Transgenic plants harboring constructs containing different numbers or combinations of DR cassettes were further tested to look for tissue-specific expression patterns and potential promoter response to the infiltration process employed during transient expression. Multimerization of DR elements produced enhancer activity that was in general additive, increasing reporter activity in direct proportion to the number of DR cassettes within the test promoter. In contrast, combinations of different DR cassettes often functioned synergistically, producing reporter enhancement markedly greater then the sum of the combined DR activities. Several of the DR constructs responded to Agrobacteria (lacking T-DNA) infiltration of transgenic leaves by an induction (2 elements) or reduction (1 element) in reporter activity. Combinations of DR cassettes producing the strongest enhancement of reporter activity were used to create two synthetic promoters (SynPro3 and SynPro5) that drive leaf reporter activities at levels comparable to the CaMV35S promoter. Characterization of these synthetic promoters in transformed tobacco showed strong reporter expression at all stages of development and in most tissues. The arrangement of DR elements within SynPro3 and SynPro5 appears to play a role in defining tissue-specificity of expression and/or Agrobacteria-infusion responsiveness.
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Affiliation(s)
- Christopher Ian Cazzonelli
- Plant Stress and Water Conservation Laboratory, United States Department of Agriculture-Agricultural Research Service, 3810 4th Street, Lubbock, Texas 79415, USA.
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Collens JI, Mason HS, Curtis WR. Agrobacterium-mediated viral vector-amplified transient gene expression in Nicotiana glutinosa plant tissue culture. Biotechnol Prog 2007; 23:570-6. [PMID: 17425328 DOI: 10.1021/bp060342u] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A viral vector based on the bean yellow dwarf virus was investigated for its potential to increase transient gene expression. An intron-containing GUS reporter gene and the cis-acting viral regulatory elements were incorporated in the viral vector and could be complemented by the viral replication-associated proteins provided on a secondary vector. All vectors were delivered to Nicotiana glutinosa plant cell suspension or hairy root cultures via auxotrophic Agrobacterium tumefaciens. Cell culture generated greater yield of reporter gene expression than did root culture, as a result of the limitation imposed on roots to express the protein only in surface tissue containing actively dividing cells. Reporter gene expression increased for cell culture when the reporter gene construct was co-delivered with the construct supplying both viral replication associated proteins (REP and REPA); gene expression decreased when the construct supplying only the viral REP protein was co-delivered. Reporter protein expression increased from 0.091% for the reporter construct alone to 0.22% total soluble protein (% TSP) when the viral Rep-supplying vector was co-delivered with the reporter gene construct. Reporter protein was generated 3 days after the initiation of bacterial co-culture, providing for rapid generation of heterologous protein in cell culture.
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Affiliation(s)
- Jason I Collens
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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11
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Hefferon KL, Moon YS, Fan Y. Multi-tasking of nonstructural gene products is required for bean yellow dwarf geminivirus transcriptional regulation. FEBS J 2006; 273:4482-94. [PMID: 16972938 DOI: 10.1111/j.1742-4658.2006.05454.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mastreviridae, of the family geminiviridae, possess a monopartite genome and are transmitted by leafhoppers. Bean yellow dwarf dirus (BeYDV) is a mastrevirus which originated from South Africa and infects dicoyledenous plants, a feature unusual for mastreviridae. Previously, the nonstructural proteins Rep and RepA were examined with respect to their independent roles in BeYDV replication. This was achieved by placing both gene products under independent constitutive promoter control and examining their effects on replication-competent constructs. In the current study, Rep and RepA are examined further for their roles in regulating BeYDV gene expression using a series of replication-incompetent constructs. While both Rep and RepA are found to behave as equally potent inhibitors of complementary-sense gene expression, they differ considerably with respect to their abilities to transactivate virion-sense gene expression. Furthermore, RepA is identified as playing more than one role in this transactivation process. A nuclear localization domain is identified in Rep which is absent in RepA, and Rep-RepA interactions are examined under in vivo conditions. The study concludes with an investigation into the expression strategies of the BeYDV capsid protein.
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12
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Romero CM, DeShazer D, Feldblyum T, Ravel J, Woods D, Kim HS, Yu Y, Ronning CM, Nierman WC. Genome sequence alterations detected upon passage of Burkholderia mallei ATCC 23344 in culture and in mammalian hosts. BMC Genomics 2006; 7:228. [PMID: 16953889 PMCID: PMC1574311 DOI: 10.1186/1471-2164-7-228] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Accepted: 09/05/2006] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND More than 12,000 simple sequence repeats (SSRs) have been identified in the genome of Burkholderia mallei ATCC 23344. As a demonstrated mechanism of phase variation in other pathogenic bacteria, these may function as mutable loci leading to altered protein expression or structure variation. To determine if such alterations are occurring in vivo, the genomes of various single-colony passaged B. mallei ATCC 23344 isolates, one from each source, were sequenced from culture, a mouse, a horse, and two isolates from a single human patient, and the sequence compared to the published B. mallei ATCC 23344 genome sequence. RESULTS Forty-nine insertions and deletions (indels) were detected at SSRs in the five passaged strains, a majority of which (67.3%) were located within noncoding areas, suggesting that such regions are more tolerant of sequence alterations. Expression profiling of the two human passaged isolates compared to the strain before passage revealed alterations in the mRNA levels of multiple genes when grown in culture. CONCLUSION These data support the notion that genome variability upon passage is a feature of B. mallei ATCC23344, and that within a host B. mallei generates a diverse population of clones that accumulate genome sequence variation at SSR and other loci.
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Affiliation(s)
- Claudia M Romero
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - Tamara Feldblyum
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Jacques Ravel
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Donald Woods
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Centre, Calgary, Alberta T2N 4N1, Canada
| | - H Stanley Kim
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Yan Yu
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Catherine M Ronning
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - William C Nierman
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
- The George Washington University School of Medicine, Departmentof Biochemistry and Molecular Biology, 2300 Eye Street NW, Washington, DC 20037, USA
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Cazzonelli CI, Velten J. An in vivo, luciferase-based, Agrobacterium-infiltration assay system: implications for post-transcriptional gene silencing. PLANTA 2006; 224:582-97. [PMID: 16523348 DOI: 10.1007/s00425-006-0250-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Accepted: 02/07/2006] [Indexed: 05/03/2023]
Abstract
An in vivo assay system for analyzing transient luciferase expression in tobacco leaves infused with Agrobacterium tumefaciens is described. The system makes use of A. tumefaciens harboring T-DNA vectors containing either an intron-containing firefly (Photinus pyralis) luciferase (EC 1.13.12.7) gene or an intron-containing sea pansy (Renilla reniformis) luciferase (EC 1.13.12.5) gene. Single or mixed Agrobacterium lines were infiltrated into leaf tissues (Nicotiana tabacum or Nicotiana benthamiana) through stomatal openings and leaf disks from infused areas floated on reaction buffers specific to each enzyme. Photons emitted were then measured to determine reporter gene activity. Parameters affecting assay reliability and sensitivity were tested, including: buffer composition; bacterial density; infusion location; reaction kinetics; and environmental factors (light and temperature). The resulting in vivo assay system generates results comparable to those obtained using a commercially available in vitro dual-luciferase(R) reporter gene assay, and reports relative expression levels, as well as induction characteristics, analogous to those obtained using leaf tissue from stably transformed plants harboring the same promoter::gene constructs. Light and temperature were observed to markedly impact transient reporter activities. Co-expression of viral suppressors of post-transcriptional gene silencing (PTGS), HcPro, p19 and AC2, confirms the occurrence of PTGS within infused zones, and provides a convenient mechanism for PTGS analysis. The in vivo transient assay was used to examine the effect on PTGS of factors such as: promoter strength; incubation temperature and double-stranded RNA production. Results from these assays provide insight into the mechanism(s) used by plants to trigger and maintain PTGS.
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Affiliation(s)
- Christopher Ian Cazzonelli
- United States Department of Agriculture-Agricultural Research Services, 3810 4th Street, Lubbock, TX 79415, USA
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Cazzonelli CI, Burke J, Velten J. Functional characterization of the geminiviral conserved late element (CLE) in uninfected tobacco. PLANT MOLECULAR BIOLOGY 2005; 58:465-81. [PMID: 16021333 DOI: 10.1007/s11103-005-6589-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Accepted: 04/27/2005] [Indexed: 05/03/2023]
Abstract
The conserved late element (CLE) was originally identified as an evolutionarily conserved DNA sequence present in geminiviral intergenic regions. CLE has subsequently been observed in promoter sequences of bacterial (T-DNA) and plant origin, suggesting a role in plant and plant viral gene regulation. Synthetic DNA cassettes harboring direct repeats of the CLE motif were placed upstream from a -46 to +1 minimal CaMV 35S promoter-luciferase reporter gene and reporter activity characterized in Nicotiana species during both transient and stable expression. A single direct-repeat cassette of the element (2x CLE) enhances luciferase activity by 2-fold, independent of the element's orientation, while multiple copies of the cassette (4-12x CLE) increases activity up to 10- to 15-fold in an additive manner. Transgenic tobacco lines containing synthetic CLE promoter constructs enhance luciferase expression in leaf, cotyledon and stem tissues, but to a lesser extent in roots. Single nucleotide substitution at six of eight positions within the CLE consensus (GTGGTCCC) eliminates CLE enhancer-like activity. It has been previously reported that CLE interacts with the AC2 protein from Pepper Huasteco Virus (PHV-AC2). PHV-AC2 (also called AL2 or C2) is a member of the transcriptional activator protein, or TrAP, gene family. In transient and stable expression systems PHV-AC2 expression was found to result in a 2-fold increase in luciferase activity, irrespective of the presence of CLE consensus sequences within the reporter's promoter. These data suggests that the PHV-AC2 protein, instead of interacting directly with CLE, functions as either a general transcriptional activator and/or a suppressor of post-transcriptional gene silencing.
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Affiliation(s)
- Christopher Ian Cazzonelli
- USDA-ARS (United States Department of Agriculture-Agricultural Research Services), Lubbock, TX 79415, USA
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