My research interests include elucidating the role of posttranslational modification of nuclear and cytosolic proteins with O-linked N-acetylglucosamine (O-GlcNAc) in plant growth and development. In Arabidopsis thaliana this modification is made by two O-GlcNAc transferases called SPINDLY and SECRET AGENT. Genetic studies with spindly and secret agent mutants show that O-GlcNAc modification regulates gibberellin and cytokinin signaling and is involved in other process such as light responses and circadian rhythms. Currently we are identifying the proteins that are modified by SPINDLY and SECRET AGENT. We are particularly interested in identifying the components of plant signal transduction pathways that are subject to this modification and then determining the effect of the O-GlcNAc modification on the activity of these proteins.
Another project studies plant pararetroviruses viruses. These viruses, which infect many plant species, including important crop species, replicate by reverse transcription producing virions containing a circular double-stranded DNA. DNA from some of these viruses is integrated into the nuclear genome of host plants. These integrated sequences are believed both to cause infection and to confer immunity to infection by viruses that are transmitted into these plants. We are studying the role of the integrated sequences in infection and immunity and are also elucidating the function of virally encoded proteins in the infection process.
Jacobsen, S.E. and Olszewski, N.E. (1993) Mutations at the spindly locus of Arabidopsis alter gibberellin signal transduction. The Plant cell 5:887-896.
Jacobsen, S.E. and Olszewski, N.E. (1996) SPINDLY , a tetratricopeptide repeat protein involved in gibberellin signal transduction in Arabidopsis . Proc. Nat. Acad. Sci . 93:9292-9296.
Cheng, C.-P., Lockhart B.E. and Olszewski, N.E. (1996) The ORFI and II Proteins of Commelina Yellow Mottle Badnavirus are Virion-Associated. Virology 223:263-271.
Tzafrir, I., Ayala-Navarrete, L., Lockhart, B.E.L., and Olszewski, N.E. (1997) The N-terminal Portion of the 216 Kilodalton Polyprotein of Commelina yellow mottle badnavirus is Required for Virus Movement but not for Replication. Virology 232: 359-368.
Tzafrir, I., Torbert, K.A., Lockhart, B.E.L., Somers, D.A. and Olszewski, N.E. (1998) The sugarcane bacilliform virus promoter is active in both monocots and dicots. Plant Molecular Biology 347-356.
Cheng, C.-P., Tzafrir, I., Lockhart, B.E. and Olszewski, N.E. (1998) Tubules Containing Virus Particles Are Present in Plant Tissues Infected with Commelina Yellow Mottle Badnavirus. J. Gen. Virol. 79: 925-929.
Ndowora, T., Dahal, G., LaFleur, D., Harper, G., Hull, R., Olszewski, N. and Lockhart, B. (1999) Evidence that badnavirus infection in Musa can originate from integrated pararetroviral sequences. Virology 255: 214-220.
Tseng, T.-S., Swain, S.and Olszewski, N.E. (2001) Ectopic Expression of the TPR Domain of SPY Causes Defects in Gibberellin Response. Plant Physiol 126: 1250-1258.
Swain, S.M., Tseng, T.-S. and Olszewski, N.E. (2001) Altered expression of SPINDLY affects gibberellin response and plant development. Plant Physiol 126: 1174-1185.
Geering A.D.W., Olszewski N.E., Dahal G., Thomas J.E., Lockhart B.E.L. (2001) Analysis of the distribution and structure of integrated Banana streak virus DNA in a range of Musa cultivars. Molecular Plant Pathology. 2: 207-213.
Swain, S.M., Tseng, T.-S., Thornton, T., Gopalraj, M. and Olszewski, N.E. (2002) SPINDLY is a nuclear-localized repressor of gibberellin signal transduction expressed throughout the plant. Plant Physiol. 129: 605-615.
Hartweck LM, Scott CL, Olszewski N.E. (2002) Two O-Linked N-Acetylglucosamine Transferase Genes of Arabidopsis thaliana L. Heynh. Have Overlapping Functions Necessary for Gamete and Seed Development. Genetics 161: 1279-1291.
Tseng, T.-S, Salomé, P. A., McClung, C. R. and Olszewski, N.E. (2004) SPINDLY and GIGANTEA interact and act in Arabidopsis thaliana pathways involved in light responses, flowering and rhythms in cotyledon movements. Plant Cell 16: 1550-1563.
Al-Saady, N.A., Torbert, K.A. Smith, L., Makarevitch, I., Baldridge, G., Zeyen, R.J., Muehlbauer, G.J., Olszewski, N.E. and Somers, D.A. (2004) Tissue specificity of sugarcane bacilliform virus promoter in oat, barley and wheat. Molecular Breeding 14: 331-338.
Greenboim-Wainberg Y., Maymon I., Borochov R., Alvarez J., Olszewski N., Ori N., Eshed Y., and Weiss D. (2005) Cross Talk between Gibberellin and Cytokinin: The Arabidopsis GA-Response Inhibitor SPINDLY Plays a Positive Role in Cytokinin Signaling. Plant Cell, 17: 92-102.
Chen, D. , Juárez, S., Hartweck, L., Alamillo, J.M., Simón-Mateo, C., Pérez, J.J., Fernández-Fernández, M.R., Olszewski, N.E. and García, J.A. (2005) Identification of SECRET AGENT as the O-GlcNAc Transferase that participates in plum pox virus infection. J. Gen. Virol., 79: 9381-9387.
Hartweck, L.M. and Olszewski, N.E. (2006) SECRET AGENT and SPINDLY have overlapping roles in the development of Arabidopsis thaliana L. Heyn. J. Exp. Bot. 57: 865-875.