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Robinson SJ, Tang LH, Mooney BAG, McKay SJ, Clarke WE, Links MG, Karcz S, Regan S, Wu YY, Gruber MY, Cui D, Yu M, Parkin IAP. An archived activation tagged population of Arabidopsis thaliana to facilitate forward genetics approaches. BMC Plant Biol 2009; 9:101. [PMID: 19646253 PMCID: PMC3091532 DOI: 10.1186/1471-2229-9-101] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 07/31/2009] [Indexed: 05/18/2023]
Abstract
BACKGROUND Functional genomics tools provide researchers with the ability to apply high-throughput techniques to determine the function and interaction of a diverse range of genes. Mutagenized plant populations are one such resource that facilitate gene characterisation. They allow complex physiological responses to be correlated with the expression of single genes in planta, through either reverse genetics where target genes are mutagenized to assay the affect, or through forward genetics where populations of mutant lines are screened to identify those whose phenotype diverges from wild type for a particular trait. One limitation of these types of populations is the prevalence of gene redundancy within plant genomes, which can mask the affect of individual genes. Activation or enhancer populations, which not only provide knock-out but also dominant activation mutations, can facilitate the study of such genes. RESULTS We have developed a population of almost 50,000 activation tagged A. thaliana lines that have been archived as individual lines to the T3 generation. The population is an excellent tool for both reverse and forward genetic screens and has been used successfully to identify a number of novel mutants. Insertion site sequences have been generated and mapped for 15,507 lines to enable further application of the population, while providing a clear distribution of T-DNA insertions across the genome. The population is being screened for a number of biochemical and developmental phenotypes, provisional data identifying novel alleles and genes controlling steps in proanthocyanidin biosynthesis and trichome development is presented. CONCLUSION This publicly available population provides an additional tool for plant researcher's to assist with determining gene function for the many as yet uncharacterised genes annotated within the Arabidopsis genome sequence http://aafc-aac.usask.ca/FST. The presence of enhancer elements on the inserted T-DNA molecule allows both knock-out and dominant activation phenotypes to be identified for traits of interest.
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Affiliation(s)
- Stephen J Robinson
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
| | - Lily H Tang
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
| | - Brent AG Mooney
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
| | - Sheldon J McKay
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Wayne E Clarke
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
| | - Matthew G Links
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
| | - Steven Karcz
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
| | - Sharon Regan
- Department of Biology, Biosciences Complex, Queens University, Kingston, Ontario, K7L 3N6, Canada
| | - Yun-Yun Wu
- Department of Biology, Biosciences Complex, Queens University, Kingston, Ontario, K7L 3N6, Canada
| | - Margaret Y Gruber
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
| | - Dejun Cui
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
| | - Min Yu
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
| | - Isobel AP Parkin
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, S7N 0X2, Canada
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van Es HH, Karcz S, Chu F, Cowman AF, Vidal S, Gros P, Schurr E. Expression of the plasmodial pfmdr1 gene in mammalian cells is associated with increased susceptibility to chloroquine. Mol Cell Biol 1994; 14:2419-28. [PMID: 7511206 PMCID: PMC358609 DOI: 10.1128/mcb.14.4.2419-2428.1994] [Citation(s) in RCA: 8] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Chloroquine (CQ)-resistant (CQR) Plasmodium falciparum malaria parasites show a strong decrease in CQ accumulation in comparison with chloroquine-sensitive parasites. Controversy exists over the role of the plasmodial pfmdr1 gene in the CQR phenotype. pfmdr1 is a member of the superfamily of ATP-binding cassette transporters. Other members of this family are the mammalian multidrug resistance genes and the CFTR gene. We have expressed the pfmdr1-encoded protein, Pgh1, in CHO cells and Xenopus oocytes. CHO cells expressing the Pgh1 protein demonstrated an increased, verapamil-insensitive susceptibility to CQ. Conversely, no increase in drug susceptibility to primaquine, quinine, adriamycin, or colchicine was observed in Pgh1-expressing cells. CQ uptake experiments revealed an increased, ATP-dependent accumulation of CQ in Pgh1-expressing cells over the level in nonexpressing control cells. The increased CQ accumulation in Pgh1-expressing cells coincided with an enhanced in vivo inhibition of lysosomal alpha-galactosidase by CQ. CHO cells expressing Pgh1 carrying two of the CQR-associated Pgh1 amino acid changes (S1034C and N1042D) did not display an increased CQ sensitivity. Immunofluorescence experiments revealed an intracellular localization of both mutant and wild-type forms of Pgh1. We conclude from our results that wild-type Pgh1 protein can mediate an increased intracellular accumulation of CQ and that this function is impaired in CQR-associated mutant forms of the protein. We speculate that the Pgh1 protein plays an important role in CQ import in CQ-sensitive malaria parasites.
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Affiliation(s)
- H H van Es
- Department of Medicine, McGill University, Montréal, Québec, Canada
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Abstract
The chloroquine resistance phenotype of Plasmodium falciparum shares many similarities to multi-drug resistance in tumour cells and this has led to the identification of two mdr-like genes (pfmdr1, pfmdr2) from this human pathogen. The pfmdr1 gene has been linked to the chloroquine resistance phenotype, although a genetic cross appears to contradict these results. Analysis of drug resistant mutants selected in vitro has shown that the level of expression of the pfmdr1 gene can affect resistance to chloroquine, mefloquine, halofantrine and quinine. Mefloquine isolates from the field appear to always contain amplified levels of the pfmdr1 gene and also overexpress the transcript. They are also resistant to halofantrine suggesting a true multi-drug resistant phenotype.
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Affiliation(s)
- A F Cowman
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
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Abstract
Resistance to chloroquine in Plasmodium falciparum bears a striking similarity to the multi-drug resistance (MDR) phenotype of mammalian tumor cells which is mediated by overexpression of P-glycoprotein. We show here that the P. falciparum homologue of the P-glycoprotein (Pgh1) is a 160,000-D protein that is expressed throughout the asexual erythrocytic life cycle of the parasite. Quantitative immunoblotting analysis has shown that the protein is expressed at approximately equal levels in chloroquine resistant and sensitive isolates suggesting that overexpression of Pgh1 is not essential for chloroquine resistance. The chloroquine-resistant cloned line FAC8 however, does express approximately threefold more Pgh1 protein than other isolates which is most likely because of the increased pfmdr1 gene copy number present in this isolate. Immunofluorescence and immunoelectron microscopy has demonstrated that Pgh1 is localized on the membrane of the digestive vacuole of mature parasites. This subcellular localization suggests that Pgh1 may modulate intracellular chloroquine concentrations and has important implications for the normal physiological function of this protein.
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Affiliation(s)
- A F Cowman
- Walter and Eliza Hall Institute of Medical Research, Melbourne Victoria, Australia
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