@article{mowat_hash_mzyk_harned_nagar_mcgahan_2016, title={Evaluation of the proliferative capacity of canine retinal pigment epithelial cells harvested from different regions of the fundus}, volume={57}, number={12}, journal={Investigative Ophthalmology and Visual Science}, author={Mowat, F. M. and Hash, J. and Mzyk, P. and Harned, J. and Nagar, S. and McGahan, M. C.}, year={2016} }
 @article{harned_nagar_mcgahan_2014, title={Hypoxia controls iron metabolism and glutamate secretion in retinal pigmented epithelial cells}, volume={1840}, ISSN={["1872-8006"]}, DOI={10.1016/j.bbagen.2014.06.012}, abstractNote={Blood-barrier systems are essential in controlling iron levels in organs such as the brain and eye, both of which experience hypoxia in pathological conditions. While hypoxia's effects on numerous iron regulatory and storage proteins have been studied, little is known about how hypoxia affects iron metabolism. Iron also controls glutamate production and secretion; therefore the effects of hypoxia on iron metabolism and glutamate secretion were studied in polarized retinal pigmented epithelial (RPE) cells. Primary canine RPE were cultured in Millicells to create polarized cell cultures. Iron uptake and efflux were measured in hypoxic and normoxic conditions. RPE were loaded with 59Fe-transferrin. Glutamate concentrations in the cell conditioned media were also measured. Hypoxia induced a large increase in iron efflux from RPE in the basolateral direction. Glutamate secretion occurred mainly in the basolateral direction which is away from the retina and out of the eye in vivo. Glutamate secretion was doubled under hypoxic conditions. Hypoxia is known to induce oxidative damage. The current results show that iron, a key catalyst of free radical generation, is removed from RPE under hypoxic conditions which may help protect RPE from oxidative stress. Results obtained here indicate the importance of using polarized tight junctional cells as more physiologically relevant models for blood-barrier-like systems. While the effects of hypoxia on iron efflux and glutamate secretion may be protective for RPE cells and retina, increased glutamate secretion in the brain could cause some of the damaging neurological effects seen in stroke.}, number={10}, journal={BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS}, author={Harned, Jill and Nagar, Steven and McGahan, M. Christine}, year={2014}, month={Oct}, pages={3138–3144} }
 @article{goralska_nagar_fleisher_mzyk_mcgahan_2013, title={Source-Dependent Intracellular Distribution of Iron in Lens Epithelial Cells Cultured Under Normoxic and Hypoxic Conditions}, volume={54}, ISSN={["1552-5783"]}, DOI={10.1167/iovs.13-12868}, abstractNote={PURPOSE
Intracellular iron trafficking and the characteristics of iron distribution from different sources are poorly understood. We previously determined that the lens removes excess iron from fluids of inflamed eyes. In the current study, we examined uptake and intracellular distribution of ⁵⁹Fe from iron transport protein transferrin or ferric chloride (nontransferrin-bound iron [NTBI]) in cultured canine lens epithelial cells (LECs). Because lens tissue physiologically functions under low oxygen tension, we also tested effects of hypoxia on iron trafficking. Excess iron, not bound to proteins, can be damaging to cells due to its ability to catalyze formation of reactive oxygen species.


METHODS
LECs were labeled with ⁵⁹Fe-Tf or ⁵⁹FeCl₃ under normoxic or hypoxic conditions. Cell lysates were fractioned into mitochondria-rich, nuclei-rich, and cytosolic fractions. Iron uptake and its subcellular distribution were measured by gamma counting.


RESULTS
⁵⁹Fe accumulation into LECs labeled with ⁵⁹Fe-Tf was 55-fold lower as compared with that of ⁵⁹FeCl₃. Hypoxia (24 hours) decreased uptake of iron from transferrin but not from FeCl₃. More iron from ⁵⁹FeCl₃ was directed to the mitochondria-rich fraction (32.6%-47.7%) compared with ⁵⁹Fe from transferrin (10.6%-12.6%). The opposite was found for the cytosolic fraction (8.7%-18.3% and 54.2%-46.6 %, respectively). Hypoxia significantly decreased iron accumulation in the mitochondria-rich fraction of LECs labeled with ⁵⁹Fe-Tf .


CONCLUSIONS
There are source-dependent differences in iron uptake and trafficking. Uptake and distribution of NTBI are not as strictly regulated as that of iron from transferrin. Excessive exposure to NTBI, which could occur in pathological conditions, may oxidatively damage organelles, particularly mitochondria.}, number={12}, journal={INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE}, author={Goralska, Malgorzata and Nagar, Steven and Fleisher, Lloyd N. and Mzyk, Philip and McGahan, M. Christine}, year={2013}, month={Nov}, pages={7666–7673} }
 @article{harned_ferrell_nagar_goralska_fleisher_mcgahan_2012, title={Ceruloplasmin alters intracellular iron regulated proteins and pathways: Ferritin, transferrin receptor, glutamate and hypoxia-inducible factor-1α}, volume={97}, ISSN={0014-4835}, url={http://dx.doi.org/10.1016/j.exer.2012.02.001}, DOI={10.1016/j.exer.2012.02.001}, abstractNote={Ceruloplasmin (Cp) is a ferroxidase important to the regulation of both systemic and intracellular iron levels. Cp has a critical role in iron metabolism in the brain and retina as shown in patients with aceruloplasminemia and in Cp−/−hep−/y mice where iron accumulates and neural and retinal degeneration ensue. We have previously shown that cultured lens epithelial cells (LEC) secrete Cp. The purpose of the current study was to determine if cultured retinal pigmented epithelial cells (RPE) also secrete Cp. In addition, the effects of exogenously added Cp on iron regulated proteins and pathways, ferritin, transferrin receptor, glutamate secretion and levels of hypoxia-inducible factor-1α in the nucleus were determined. Like LEC, RPE secrete Cp. Cp was found diffusely distributed within both cultured LEC and RPE, but the cell membranes had more intense staining. Exogenously added Cp caused an increase in ferritin levels in both cell types and increased secretion of glutamate. The Cp-induced increase in glutamate secretion was inhibited by both the aconitase inhibitor oxalomalic acid as well as iron chelators. As predicted by the canonical view of the iron regulatory protein (IRP) as the predominant controller of cellular iron status these results indicate that there is an increase in available iron (called the labile iron pool (LIP)) in the cytoplasm. However, both transferrin receptor (TfR) and nuclear levels of HIF-1α were increased and these results point to a decrease in available iron. Such confounding results have been found in other systems and indicate that there is a much more complex regulation of intracellularly available iron (LIP) and its downstream effects on cell metabolism. Importantly, the Cp increased production and secretion of the neurotransmitter, glutamate, is a substantive finding of clinical relevance because of the neural and retinal degeneration found in aceruloplasminemia patients. This finding and Cp-induced nuclear translocation of the hypoxia-inducible factor-1 (HIF1) subunit HIF-1α adds novel information to the list of critical pathways impacted by Cp.}, number={1}, journal={Experimental Eye Research}, publisher={Elsevier BV}, author={Harned, J. and Ferrell, J. and Nagar, S. and Goralska, M. and Fleisher, L.N. and McGahan, M.C.}, year={2012}, month={Apr}, pages={90–97} }
 @article{harned_ferrell_lall_fleisher_nagar_goralska_mcgahan_2010, title={Altered Ferritin Subunit Composition: Change in Iron Metabolism in Lens Epithelial Cells and Downstream Effects on Glutathione Levels and VEGF Secretion}, volume={51}, ISSN={["1552-5783"]}, DOI={10.1167/iovs.09-3861}, abstractNote={PURPOSE
The iron storage protein ferritin is necessary for the safe storage of iron and for protection against the production of iron-catalyzed oxidative damage. Ferritin is composed of 24 subunits of two types: heavy (H) and light (L). The ratio of these subunits is tissue specific, and alteration of this ratio can have profound effects on iron storage and availability. In the present study, siRNA for each of the chains was used to alter the ferritin H:L chain ratio and to determine the effect of these changes on ferritin synthesis, iron metabolism, and downstream effects on iron-responsive pathways in canine lens epithelial cells.


METHODS
Primary cultures of canine lens epithelial cells were used. The cells were transfected with custom-made siRNA for canine ferritin H- and L-chains. De novo ferritin synthesis was determined by labeling newly synthesized ferritin chains with 35S-methionine, immunoprecipitation, and separation by SDS-PAGE. Iron uptake into cells and incorporation into ferritin was measured by incubating the cells with 59Fe-labeled transferrin. Western blot analysis was used to determine the presence of transferrin receptor, and ELISA was used to determine total ferritin concentration. Ferritin localization in the cells was determined by immunofluorescence labeling. VEGF, glutathione secretion levels, and cystine uptake were measured.


RESULTS
FHsiRNA decreased ferritin H-chain synthesis, but doubled ferritin L-chain synthesis. FLsiRNA decreased both ferritin H- and L-chain synthesis. The degradation of ferritin H-chain was blocked by both siRNAs, whereas only FHsiRNA blocked the degradation of ferritin L-chain, which caused significant accumulation of ferritin L-chain in the cells. This excess ferritin L-chain was found in inclusion bodies, some of which were co-localized with lysosomes. Iron storage in ferritin was greatly reduced by FHsiRNA, resulting in increased iron availability, as noted by a decrease in transferrin receptor levels and iron uptake from transferrin. Increased iron availability also increased cystine uptake and glutathione concentration and decreased nuclear translocation of hypoxia-inducible factor 1-alpha and vascular endothelial growth factor (VEGF) accumulation in the cell-conditioned medium.


CONCLUSIONS
Most of the effects of altering the ferritin H:L ratio with the specific siRNAs were due to changes in the availability of iron in a labile pool. They caused significant changes in iron uptake and storage, the rate of ferritin synthesis and degradation, the secretion of VEGF, and the levels of glutathione in cultured lens epithelial cells. These profound effects clearly demonstrate that maintenance of a specific H:L ratio is part of a basic cellular homeostatic mechanism.}, number={9}, journal={INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE}, author={Harned, Jill and Ferrell, Jenny and Lall, Marilyn M. and Fleisher, Lloyd N. and Nagar, Steven and Goralska, Malgorzata and McGahan, M. Christine}, year={2010}, month={Sep}, pages={4437–4446} }
 @article{goralska_nagar_colitz_fleisher_mcgahan_2009, title={Changes in Ferritin H- and L-Chains in Canine Lenses with Age-Related Nuclear Cataract}, volume={50}, ISSN={["0146-0404"]}, DOI={10.1167/iovs.08-2230}, abstractNote={PURPOSE
To determine potential differences in the characteristics of the iron storage protein ferritin and its heavy (H) and light (L) subunits in fiber cells from cataractous and noncataractous lenses of older dogs.


METHODS
Lens fiber cell homogenates were analyzed by SDS-PAGE, and ferritin chains were immunodetected with ferritin chain-specific antibodies. Ferritin concentration was measured by ELISA. Immunohistochemistry was used to localize ferritin chains in lens sections.


RESULTS
The concentration of assembled ferritin was comparable in noncataractous and cataractous lenses of similarly aged dogs. The ferritin L-chain detected in both lens types was modified and was approximately 11 kDa larger (30 kDa) than standard L-chain (19 kDa) purified from canine liver. The H-chain identified in cataractous fiber cells (29 kDa) differed from the 21-kDa standard canine H-chain and from the 12-kDa modified H-chain present in fiber cells of noncataractous lenses. Histologic analysis revealed that the H-chain was distributed differently throughout cataractous lenses compared with noncataractous lenses. There was also a difference in subunit makeup of assembled ferritin between the two lens types. Ferritin from cataractous lenses contained more H-chain and bound 11-fold more iron than ferritin from noncataractous lenses.


CONCLUSIONS
There are significant differences in the characteristics of ferritin H-chain and its distribution in canine cataractous lenses compared with noncataractous lenses. The higher content of H-chain in assembled ferritin allows this molecule to sequester more iron. In addition, the accumulation of H-chain in deeper fiber layers of the lens may be part of a defense mechanism by which the cataractous lens limits iron-catalyzed oxidative damage.}, number={1}, journal={INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE}, author={Goralska, Malgorzata and Nagar, Steven and Colitz, Carmen M. H. and Fleisher, Lloyd N. and McGahan, M. Christine}, year={2009}, month={Jan}, pages={305–310} }
 @article{goralska_nagar_fleisher_mcgahan_2009, title={Distribution of ferritin chains in canine lenses with and without age-related nuclear cataracts}, volume={15}, number={256-59}, journal={Molecular Vision}, author={Goralska, M. and Nagar, S. and Fleisher, L. N. and McGahan, M. C.}, year={2009}, pages={2404–2410} }
 @article{goralska_ferrell_harned_lall_nagar_fleisher_mcgahan_2009, title={Iron metabolism in the eye: A review}, volume={88}, ISSN={0014-4835}, url={http://dx.doi.org/10.1016/j.exer.2008.10.026}, DOI={10.1016/j.exer.2008.10.026}, abstractNote={This review article covers all aspects of iron metabolism, which include studies of iron levels within the eye and the processes used to maintain normal levels of iron in ocular tissues. In addition, the involvement of iron in ocular pathology is explored. In each section there is a short introduction to a specific metabolic process responsible for iron homeostasis, which for the most part has been studied in non-ocular tissues. This is followed by a summary of our current knowledge of the process in ocular tissues.}, number={2}, journal={Experimental Eye Research}, publisher={Elsevier BV}, author={Goralska, M. and Ferrell, J. and Harned, J. and Lall, M. and Nagar, S. and Fleisher, L.N. and McGahan, M.C.}, year={2009}, month={Feb}, pages={204–215} }
 @article{lall_ferrell_nagar_fleisher_mcgahan_2008, title={Iron regulates L-cystine uptake and glutathione levels in lens epithelial and retinal pigment epithelial cells by its effect on cytosolic aconitase}, volume={49}, ISSN={["1552-5783"]}, DOI={10.1167/iovs.07-1041}, abstractNote={PURPOSE
The authors previously published the novel finding that iron regulates L-glutamate synthesis and accumulation in the cell-conditioned medium (CCM) by increasing cytosolic aconitase activity in cultured lens epithelial cells (LECs), retinal pigment epithelial (RPE) cells, and neurons. The present study was designed to determine whether iron-induced L-glutamate accumulation in the CCM regulates L-cystine uptake and glutathione (GSH) levels through the aconitase pathway in LECs and RPE cells.


METHODS
The presence of xCT, the light chain of X(c)(-), a glutamate/cystine antiporter, was analyzed by RT-PCR, immunoblotting, and immunocytochemistry. Uptake of L-[(35)S]cystine and L-[(3)H]glutamate was measured in the presence or absence of transporter inhibitors. L-cystine uptake and intracellular GSH concentration were measured in the presence or absence of iron-saturated transferrin, the iron chelator dipyridyl (DP), or oxalomalic acid (OMA), an aconitase inhibitor.


RESULTS
LECs and RPE cells express xCT, as evidenced by RT-PCR analysis and immunoblotting. xCT was localized by immunocytochemistry. The authors found that the iron-induced increase in L-glutamate availability increased L-cystine uptake, with subsequent increases in GSH levels. In addition, L-glutamate production, L-cystine uptake, and GSH concentration were inhibited by OMA and DP, indicating a central role for iron-regulated aconitase activity in GSH synthesis in LECs and RPE cells.


CONCLUSIONS
These results demonstrate for the first time that iron regulates L-cystine uptake and the downstream production of GSH in two mammalian cell types. It is possible that the increase in intracellular antioxidant concentration induced by iron serves as a protective mechanism against the well-established capacity of iron to induce oxidative damage.}, number={1}, journal={INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE}, author={Lall, Marilyn M. and Ferrell, Jenny and Nagar, Steve and Fleisher, Lloyd N. and McGahan, M. Christine}, year={2008}, month={Jan}, pages={310–319} }
 @article{goralska_nagar_fleisher_mcgahan_2005, title={Differential degradation of ferritin H- and L-chains: Accumulation of L-chain-rich ferritin in lens epithelial cells}, volume={46}, ISSN={["0146-0404"]}, DOI={10.1167/iovs.05-0358}, abstractNote={PURPOSE
The storage of iron by ferritin is determined by tissue-specific composition of its 24 subunits, which are designated as either heavy (H) or light (L). For a better understanding of how lens epithelial cells regulate their ferritin subunit makeup, the degradation pattern of each subunit type was analyzed. In addition, age-related changes in ferritin concentration and subunit makeup were determined.


METHODS
Ferritin turnover in primary cultures of canine lens epithelial cells was determined by metabolic labeling with [(35)S]-methionine. Transient transfection with vectors containing coding sequences for either H- or L-chains were used to modify ferritin subunit makeup. Ferritin concentration was measured by ELISA. Immunodetection and fluorescence immunocytochemistry were used to study age-related changes in ferritin chain concentration.


RESULTS
Inhibition of the proteasomal protein degradation pathway by clastolactacystin-beta-lactone had no effect on ferritin degradation, whereas inhibition of lysosomal degradation markedly increased ferritin levels, confirming that this system is involved in ferritin turnover. H-chain ferritin degraded at a faster rate than the L-chain. L-chain-rich ferritin in L-chain-transfected cells formed inclusion bodies that were localized to the cytosol. Similar inclusion bodies were found in older lens cells kept in cell culture for more than 8 days.


CONCLUSIONS
Steady degradation of H-chain ferritin contributed to the maintenance of a constant level of this chain within the lens epithelial cells. In contrast, slower turnover of the L-chain resulted in accumulation of L-chain-enriched ferritin associated with cytoplasmic inclusion bodies. These L-chain-containing inclusion bodies were found in the cytosol of cells overexpressing L-ferritin chain and in nontransfected cells maintained in culture for 8 to 35 days. Overexpression of the L-chain has been associated with the formation of premature cataracts in humans with hereditary hyperferritinemia cataract syndrome. The formation of inclusion bodies in older lens epithelial cells, as demonstrated in the current investigation, is intriguing and could point to possible involvement of cytoplasmic L-chain-enriched ferritin aggregates in the formation of age-related cataract.}, number={10}, journal={INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE}, author={Goralska, M and Nagar, S and Fleisher, LN and McGahan, MC}, year={2005}, month={Oct}, pages={3521–3529} }
 @article{nagara_hanley-bowdoin_robertson_2002, title={Host DNA replication is induced by geminivirus infection of differentiated plant cells}, volume={14}, ISSN={["1040-4651"]}, DOI={10.1105/tpc.005777}, abstractNote={The geminivirus Tomato golden mosaic virus (TGMV) replicates in differentiated plant cells using host DNA synthesis machinery. We used 5-bromo-2-deoxyuridine (BrdU) incorporation to examine DNA synthesis directly in infected Nicotiana benthamiana plants to determine if viral reprogramming of host replication controls had an impact on host DNA replication. Immunoblot analysis revealed that up to 17-fold more BrdU was incorporated into chromosomal DNA of TGMV-infected versus mock-infected, similarly treated healthy leaves. Colocalization studies of viral DNA and BrdU demonstrated that BrdU incorporation was specific to infected cells and was associated with both host and viral DNA. TGMV and host DNA synthesis were inhibited differentially by aphidicolin but were equally sensitive to hydroxyurea. Short BrdU labeling times resulted in some infected cells showing punctate foci associated with host DNA. Longer periods showed BrdU label uniformly throughout host DNA, some of which showed condensed chromatin, only in infected nuclei. By contrast, BrdU associated with viral DNA was centralized and showed uniform, compartmentalized labeling. Our results demonstrate that chromosomal DNA is replicated in TGMV-infected cells.}, number={12}, journal={PLANT CELL}, author={Nagara, S and Hanley-Bowdoin, L and Robertson, D}, year={2002}, month={Dec}, pages={2995–3007} }
 @article{kong_orozco_roe_nagar_ou_feiler_durfee_miller_gruissem_robertson_et al._2000, title={A geminivirus replication protein interacts with the retinoblastoma protein through a novel domain to determine symptoms and tissue specificity of infection in plants}, volume={19}, ISSN={["0261-4189"]}, DOI={10.1093/emboj/19.13.3485}, abstractNote={Geminiviruses replicate in nuclei of mature plant cells after inducing the accumulation of host DNA replication machinery. Earlier studies showed that the viral replication factor, AL1, is sufficient for host induction and interacts with the cell cycle regulator, retinoblastoma (pRb). Unlike other DNA virus proteins, AL1 does not contain the pRb binding consensus, LXCXE, and interacts with plant pRb homo logues (pRBR) through a novel amino acid sequence. We mapped the pRBR binding domain of AL1 between amino acids 101 and 180 and identified two mutants that are differentially impacted for AL1–pRBR interactions. Plants infected with the E‐N140 mutant, which is wild‐type for pRBR binding, developed wild‐type symptoms and accumulated viral DNA and AL1 protein in epidermal, mesophyll and vascular cells of mature leaves. Plants inoculated with the KEE146 mutant, which retains 16% pRBR binding activity, only developed chlorosis along the veins, and viral DNA, AL1 protein and the host DNA synthesis factor, proliferating cell nuclear antigen, were localized to vascular tissue. These results established the importance of AL1–pRBR interactions during geminivirus infection of plants.}, number={13}, journal={EMBO JOURNAL}, author={Kong, LJ and Orozco, BM and Roe, JL and Nagar, S and Ou, S and Feiler, HS and Durfee, T and Miller, AB and Gruissem, W and Robertson, D and et al.}, year={2000}, month={Jul}, pages={3485–3495} }
 @article{bass_nagar_hanley-bowdoin_robertson_2000, title={Chromosome condensation induced by geminivirus infection of mature plant cells}, volume={113}, number={7}, journal={Journal of Cell Science}, author={Bass, H. W. and Nagar, S. and Hanley-Bowdoin, L. and Robertson, D.}, year={2000}, pages={1149–1160} }
 @article{hanley-bowdoin_settlage_orozco_nagar_robertson_2000, title={Geminiviruses - Models for plant DNA replication, transcription and cell cycle regulation ([correction to] vol 35, pg 105, 2000)}, volume={35}, number={4}, journal={Critical Reviews in Biochemistry and Molecular Biology}, author={Hanley-Bowdoin, L. and Settlage, S. B. and Orozco, B. M. and Nagar, S. and Robertson, D.}, year={2000}, pages={U4} }
 @article{hanley-bowdoin_settlage_orozco_nagar_robertson_2000, title={Geminiviruses: Models for plant DNA replication, transcription, and cell cycle regulation}, volume={35}, number={2}, journal={Critical Reviews in Biochemistry and Molecular Biology}, author={Hanley-Bowdoin, L. and Settlage, S. B. and Orozco, B. M. and Nagar, S. and Robertson, D.}, year={2000}, pages={105–140} }
 @article{hanley-bowdoin_settlage_orozco_nagar_robertson_1999, title={Geminiviruses: Models for plant DNA replication, transcription, and cell cycle regulation {review}}, volume={18}, DOI={10.1080/07352689991309162}, abstractNote={Geminiviruses have small, single-stranded DNA genomes that replicate through double-stranded intermediates in the nuclei of infected plant cells. Viral double-stranded DNA also assembles into minichromosomes and is transcribed in infected cells. Geminiviruses encode only a few proteins for their replication and transcription and rely on host enzymes for these processes. However, most plant cells, which have exited the cell cycle and undergone differentiation, do not contain the replicative enzymes necessary for viral DNA synthesis. To overcome this barrier, geminiviruses induce the accumulation of DNA replication machinery in mature plant cells, most likely by modifying cell cycle and transcriptional controls. In animals, several DNA viruses depend on host replication and transcription machinery and can alter their hosts to create an environment that facilitates efficient viral replication. Analysis of these viruses and their proteins has contributed significantly to our understanding of DNA replication, transcription, and cell cycle regulation in mammalian cells. Geminiviruses have the same potential for plant systems. Plants offer many advantages for these types of studies, including ease of transformation, well-defined cell populations and developmental programs, and greater tolerance of cell cycle perturbation and polyploidy. Our knowledge of the molecular and cellular events that mediate geminivirus infection has increased significantly during recent years. The goal of this review is to summarize recent research addressing geminivirus DNA replication and its integration with transcriptional and cell cycle regulatory processes.}, number={1}, journal={Critical Reviews in Plant Sciences}, author={Hanley-Bowdoin, L. and Settlage, S. B. and Orozco, B. M. and Nagar, S. and Robertson, D.}, year={1999}, pages={71–106} }
 @article{nagar_pedersen_carrick_hanley-bowdoin_robertson_1995, title={A geminivirus induces expression of a host DNA synthesis protein in terminally differentiated plant cells}, volume={7}, DOI={10.2307/3870173}, number={6}, journal={Plant Cell}, author={Nagar, S. and Pedersen, T. J. and Carrick, K. M. and Hanley-Bowdoin, L. and Robertson, D.}, year={1995}, pages={705} }