Center for Plant Science Innovation

Research Interests

Dr. Van Etten studies a family of large, polyhedral, plaque forming, dsDNA viruses that replicate in certain eukaryotic unicellular Chlorella-like green algae. The genomes of the chlorella viruses are 330kb or larger in size and contain at least 375 protein encoding genes and many TRNA genes. Approximately 50% of the virus gene products have been tentatively identified, many of which are completely unexpected. For example, the viruses code for DNA methyltransferases and DNA restriction endonucleases, sugar manipulating enzymes, and a potassium ion channel protein. The plaque assay, the ability to synchronously infect the host, the short life cycle, and the ability of the viruses to undergo homologous recombination make them excellent model systems for studying DNA replication and gene expression in a photosynthetic eukaryote.

Recent Papers

Recent Publications

Dickey, J.S., T-J. Choi, J.L. Van Etten, and N. Osheroff. (2005). Chlorella virus Marburg topoisomerase II: high DNA cleavage activity as a characteristic of chlorella virus type II enzymes. Biochemistry 44, 3899-3908.

Zhang, Y., H. Moriyama, K. Homma, K., and J.L. Van Etten. (2005). Characterization of deoxyuridine triphosphatases from chlorella viruses. J. Virol. 79, 9945-9953.

Dickey, J.S., J.L. Van Etten, and N. Osheroff. (2005). DNA methylation impacts the cleavage activity of chlorella virus topoisomerase II. Biochemistry 44, 15378-15386.

Yan, X., V. Bowman, N.H. Olson, J.R. Gurnon, J.L. Van Etten, M.G. Rossmann, and T.S. baker. (2005). The structure of a T=169d algal virus, PBCV-1, at 15 Â resolution. Microsc. Microanal. 11, 1056-1057.

Moroni, A., J.L. Van Etten, and G. Thiel. (2005). Structure and function of a viral encoded K+ channel. In Viral Membrane Proteins: Structure, Function, Drug Design. W.Fischer (ed). Kluwer Academic/Plenum Publishers p. 21-32.

Kang, M., D.D. Dunigan, and J.L. Van Etten. (2005). Chloroviruses: a genus of Phycodnaviridae that infect certain chlorella-like green algae. Mol. Plant Path. 6, 213-224.

Dunigan, D.D., L.A. Fitzgerald, and J.L. Van Etten. (2006). Phycodnaviruses: a peek at genetic diversity. Virus Res. 117, 119-132.

Yamada, T., H. Onimatsu, and J.L. Van Etten. (2006). Chlorella viruses. Adv. in Virus Res. 66, 293-340.

Frohns, F., A. Kasmann, D. Kramer, B. Schafer, M. Mehmel, M. Kang, J.L. Van Etten, S. Gazzarrini, A. Moroni, and G. Thiel. (2006). Potassium channels of chlorella viruses cause rapid depolarization of host cells during infection. J. Virol. 80, 2437-2444.

Gazzarrini S., M. Kang, S. Epimashko, J.L. Van Etten, J. Dainty, G. Thiel, and A. Moroni. (2006). Chlorella virus MT325 encodes water and potassium channels that interact synergistically. Proc. Natl. Acad. Sci. USA 103, 5355-5360.

Hertel, B., S. Tayefeh, M. Mehmel, S.M. Kast, J.L. Van Etten, A. Moroni, and G. Thiel, (2006). Elongation of outer transmembrane domain alters function of miniature K+ channel Kcv. J. Membrane Biol. 210, 1-9.

Chan, S-H., Z. Zhu, D.D. Dunigan, J.L. Van Etten, and S-Y. Xu. (2006). Cloning of Nt.CviQII nicking endonuclease and its cognate methyltransferase: M.CviQII methylates AG sequences. Prot. Express. Purif. 49, 138-150.

Agarkova, I.V., D.D. Dunigan, and J.L Van Etten. (2006). Virion-associated restriction endonucleases of chloroviruses. J. Virol. 80, 8114-8123. [highlighted article]

Fitzgerald, L.A., M.V. Graves, X. Li, T. Feldblyum, W.C. Nierman, and J.L. Van Etten. (2007). Sequence and annotation of the 369-kb NY-2A and the 345-kb AR158 viruses that infect Chlorella NC64A. Virology 358, 472-484.

Fitzgerald, L.A., M.V. Graves, X. Li, T. Feldblyum, J. Hartigan, and J.L. Van Etten. (2007). Sequence and annotation of the 314-kb MT325 and the 321-kb FR483 viruses that infect Chlorella Pbi. Virology 358, 459-471.

Baumann, S., A. Sander, J.R. Gurnon, G.M. Yanai-Balser, J.L. Van Etten, and M. Piotrowski. (2007). Chlorella viruses contain genes encoding a complete polyamine biosynthetic pathway. Virology 360, 209-217.

Fitzgerald, L.A., M.V. Graves, X. Li, J. Hartican, A.J.P. Pfitzner, E. Hoffart, and J.L. Van Etten. (2007). Sequence and annotation of the 288-kb ATCV-1 virus that infects an endosymbiotic chlorella strain of the heliozoon Acanthocystis turfacea. Virology 362, 350-361 [cover photo].

Zhang, Y., F. Maley, G.F. Maley, G. Duncan, D.D. Dunigan, and J.L. Van Etten. (2007). Chloroviruses encode a bifunctional dCMP-dCTP deaminase that produces two key intermediates in dTTP formation. J. Virol. 81, 7662-7671.

Zhang, Y., Y. Xiang, J.L. Van Etten, and M.G. Rossmann. (2007). Structure and function of a chlorella virus PBCV-1 encoded glycosyltransferase. Structure 15, 1-9.

Van Etten, J.L. (2007). Viruses that infect protists. Chapter 19 in "Fields Virology, fifth edition". (D.M. Knipe and P.M. Howley, ed.) pp. 627-640. Wolters Kluwer/Lippincott Williams & Wilkins, Philadelphia.

Van Etten, J.L. and M.V. Graves. (2008). Phycodnaviruses. In: Encyclopedia of Virology - third edition. (B.W.J. Mahy, and M.H.V. Regenmortel, eds). Elsevier, Oxford. p. 116-125.

Fruscione, F., L. Sturla, G. Duncan, J.L. Van Etten, P. Valbuzzi, A. De Flora, E. Di Zanni, and M. Tonetti. (2008). Differential role of NADP+ and NADPH in the activity and structure of GDP-D-mannose 4,6-dehydratase from two chlorella viruses. J. Biol. Chem. 283, 184-193.

Neupartl, M., C. Meyer, I. Woll, F. Frohns, M. Kang, J.L. Van Etten, D. Kramer, B. Hertel, A. Moroni, and G. Thiel. (2008). Chlorella viruses evoke a rapid release of K+ from host cells during early phase of infection. Virology 372, 340-348.

Balss, J., P. Papatheodorou, M. Mehmel, D. Baumeister, B. Hertel, N. Delaroque, F.C. Chatelain, D.L. Minor, J.L. Van Etten, J. Rassow, A. Moroni, and G. Thiel. (2008). Transmembrane domain length of viral K+ channels is a signal for mitochondria targeting. Proc. Natl. Acad. Sci. USA 105, 12313-12318.

Mujtaba, S., K.L. Manzur, J.R. Gurnon, M. Kang, J.L. Van Etten, and M-M. Kang. (2008). Epigenetic transcription repression of cellular genes by a viral SET protein. Nature Cell Biol. 10, 1114-1122.

Fitzgerald, L.A., P.T. Boucher, G. Yanai-Balser, K. Suhre, M.V. Graves, and J.L. Van Etten. (2008). Putative gene promoter sequences in the chlorella viruses. Virology (in press).

Agarkova, I., D. Dunigan, J. Gurnon, T. Greiner, J. Barres, G. Thiel, and J.L. Van Etten. (2008). Chlorovirus-mediated membrane depolarization of chlorella alters secondary active transport of solutes. J. Virol. (in press).

Wilson, W.H., J.L. Van Etten, and M.J. Allen. (2008). The Phycodnaviridae: the story of how tiny giants rule the world. In "Lesser Known Large dsDNA Viruses". (J. Van Etten, ed). Springer, Berlin. p. (in press).