James Van Etten, PhD

William Allington Distinguished Professor of Plant Pathology
University of Nebraska-Lincoln
Department of Plant Pathology
205 Morrison Center
Lincoln, NE 68583-0900
Phone: 402.472.3168
Fax: 402.472.3323

Please visit our Lab Webpage

Research Interests

Research in the Van Etten laboratory focuses on the isolation and characterization of large icosahedral, dsDNA-containing, plaque-forming viruses that infect certain unicellular, eukaryotic chlorella-like green algae.  These viruses are ubiquitous in fresh water from all over the world. The chlorella viruses have genomes as large as 370 kb that contain as many as 400 protein encoding- and 16 tRNA encoding-genes.  Besides their large genomes, the chlorella viruses have other unexpected features: (i) They encode multiple DNA methyltransferases and DNA restriction endonucleases.  (ii) Unlike other glycoprotein-containing viruses, chlorella viruses encode most, if not all, of the components required to glycosylate their proteins.  (iii) Many chlorella virus-encoded proteins are either the smallest or among the smallest proteins of their class.  Consequently, these proteins serve as models for mechanistic and structural studies.  Infection by the chlorella viruses resembles bacterial infection by tailed bacteriophages in many respects.

Selected Recent Publications

Arrigoni, C., Schroeder, I., Romani, G., Van Etten, J.L., Thiel, G., and Moroni, A. (2013). The voltage-sensing             domain of a phosphatase gates the pore of a potassium channel. J. Gen Physiol. 141, 389-395. [Highlighted article]

Jeanniard, A., Dunigan, D.D., Gurnon, J.R., Agarkova, I.V., Kang, M., Vitek, J., Duncan, G., McClung, O.W., Larsen, M., Claverie, J.M., Van Etten, J.L., Blanc, G. (2013). Towards defining the chloroviruses: a             genomic journey through a genus of large DNA viruses.  BMC Genomics 14, 158.

Rowe, J.M., Dunigan, D.D., Blanc, G., Gurnon, J.R., Xia, Y., Van Etten, J.L. (2013).  Evaluation of higher plant    virus resistance genes in the green alga, Chlorella variabilis   NC64A, during the early phase of             infection with Paramecium bursaria chlorella virus-1. Virology 442, 101-113. [Highlighted article]

Colson, P., De Lamballerie, X., Yutin, N., Asgari, S., Bigot, Y., Bideshi, D.K., Chang, X,W.,  Federici, B.A.,             Van Etten, J.L., Koonin, E.V., La Scola, B., Raoult, D. (2013). “Megavirales”, a proposed new order for       eukaryotic nucleocytoplasmic large DNA viruses. Arch. Virol. (in press).

Thiel, G., Moroni, A., Blanc, G., Van Etten, J.L. (2013). Potassium ion channels: could they have evolved from    viruses. Plant Physiol. 162, 1215-1224.

Romani, G., Piotrowski, A., Hillmer, S., Gazzarrini, S., Gurnon, J.R., Van Etten, J.L., Moroni, A., Thiel, Hertel, B. (2013). Viral encode potassium ion channel is a structural protein in the chlorovirus PBCV-1 virion.   J. Gen. Virol. (in press).

De Castro, C., Molinaro, A., Piacente, F., Gurnon, J.R., Sturiale, L., Palmigiano, A., Lanzetta, R., Parrilli, M., Garosso, D., Tonetti, M., Van Etten, J.L. (2013). Structure of the N-linked oligosaccharides attached to   virus PBCV-1 major capsid protein: an unusual class of complex N-glycans. Proc. Natl. Acad. Sci. USA    110, 13956-13960.

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, 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 380, 388-393.

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. 82, 12181-12190.

Gazzarrini, S., M. Kang, A. Abenavoli, G. Romani, C. Olivari, D. Gaslini, G. Ferrara,J.L. Van Etten, M. Kreim, S.M. Kast, G. Thiel, and A. Moroni. (2009).  Chlorellavirus ATCV1 encodes a  functional potassium channel of  eighty-two amino acids Biochem. J. 420, 295-303.

Thiel, G., A. Moroni, D. Dunigan, and J.L. Van Etten. (2010). Initial events associatedwith virus PBCV-1 infection of Chlorella NC64A. Progress in Botany (U. Lüttge, W. Beyschlag, B. Büdel, eds.) vol. 71. Springer -Verlag, Berlin. pp. 169-183.

Greiner, T., F. Frohns, M. Kang, J.L. Van Etten, A. Kaesmann, A. Moroni, B. Hertel, andG. Thiel. (2009).  Chlorella viruses prevent multiple infections by depolarizing the host membrane. J. Gen Virol. 90, 2033-2039.

Cherrier, M.V., V.A. Kostyuchenko, C. Xiao, V.D. Bowman, A.J. Battisti, X. Yan, P.R.Chipman, T.S. Baker, J.L. Van Etten, and M.G. Rossmann. (2009). An icosahedral algal virus has a complex unique vertex decorated by a spike.  Proc. Natl. Acad. Sci. USA 106, 11085-11089.

Fitzgerald, L.A., Y. Zhang, G. Lewis, J.L. Van Etten. (2009). Characterization of a monothiol glutaredoxin encoded by chlorella virus PBCV-1. Virus Genes 39, 418-426.

Van Etten, J.L., J. Gurnon, G. Yanai-Balser, D. Dunigan, M.V. Graves. (2010). Chlorella viruses encode most, if not all, of the machninery to glycosylate their glycoproteins independent of the endoplasmic reticulum.  Biochem. Biophys. Acta 1800, 152-159. [special issue on nucleo-cytoplasmic glycosylation].

Yanai-Balser, G.M., G.A. Duncan, J.D. Eudy, D. Wang, X. Li, I.V. Agarkova, D.D. Dunigan, and J.L. Van Etten. (2010). Microarray analysis of chlorella virus PBCV-1 transcription. J. Virol. 84:532-542. [highlighted article]

Fitzgerald, L.A., P.K. Wu, J.R. Gurnon, J.C. Biffinger, B.R. Ringeisen, and J.L. Van Etten. (2010). Isolation of the phycodnavirus PBCV-1 by biological laser printing (BioLP).J. Viol. Meth. 167:223-225.

Thiel, G., D. Baumeister, I. Schroeder, S.M. Kast, J.L. Van Etten, and A. Moroni. (2011). Minimal art: or why small viral K+ channels are good tools for understanding basic structure and function relations. Biochem. Biophys. Acta 1808, 580-588.  [special issue on biomembranes]

Bonza, M.C., H. Martin, M. Kang, G. Lewis, T. Greiner, S. Giacometti, J.L. Van Etten, M.I. De Michelis, G. Thiel, and A. Moroni. (2010). A functional calcium transporting ATPase encoded by chlorella viruses. J. Gen. Virol. 91, 2620-2629.

Chothi, M.P., G.A. Duncan, A. Armirotti, C. Abergel, J.R. Gurnon, J.L. Van Etten, C. Bernardi, G. Damonti, and M. Tonetti. (2010). Identification of an L-rhamnose synthetic pathway in two nucleocytoplasmic large DNA viruses. J. Virol. 84,  8829-8838.

Blanc, G., G.A. Duncan, I. Agarkova, M. Borodovsky, J. Gurnon, A. Kuo, E. Lindquist, S. Lucas, J. Pangilinan, A. Salamov, A. Terry, T. Yamada, D.D. Dunigan, I.V. Grigoriev, J.M. Claverie, and J.L. Van Etten. (2010). The Chlorella variabilis NC64A genome reveals adaptation to photosymbiosis, coevolution with and viruses and cryptic sex. Plant Cell 22, 2943-2955.

Xiang, Y., U. Baxa, Y. Zhang, A.C. Steven, G.L. Lewis, J.L. Van Etten, and M.G. Rossmann. (2010). Crystal structure of a virus encoded glycosyltransferase. J. Virol. 84, 12265-12273.

Wilson, W.H., J.L. Van Etten, and M.J. Allen. (2010). The Phycodnaviridae: the story of how tiny giants rule the world.  In "Lesser Known Large dsDNA Viruses". (J. Van Etten, ed). Springer, Berlin. p.  1-42.

Van Etten, J.L., L.C. Lane, and D.D. Dunigan. (2010). DNA viruses - the really big ones (giruses). Ann. Rev. Microbiol. 64, 83-99.

Smith, D.R., F. Burki, T. Yamada, I.V. Grigoriev, J.L. Van Etten, and P.J. Keeling. (2011). The GC-rich mitochondrial and plastid genomes of the green alga Coccomyxa give insight into the evolution of organelle DNA nucleotide landscape. PloS One 6, e23624.

Van Etten, J.L. (2011). Another really, really big virus - Commentary. Viruses 3, 32-46.

Van Etten, J.L. (2011). Giant viruses. Am. Scientist. 99, 304-311.

Zhang, X., Y. Xiang, D.D. Dunigan, T. Klose, P.R. Chipman, J.L. Van Etten, and M.G. Rossmann. (2011). Three-dimensional structure and function of the Paramecium bursaria chlorella virus capsid. Proc. Natl. Acad. Sci. USA 108, 14837-14842.

Greiner, T., Ramos, J., Alvarez, M., Gurnon, J.R., Kang, M. Van Etten, J.L., Moroni, A., and Thiel, G. (2011). A functional HAK/KUP/KT-like potassium transporter encoded by chlorella viruses.  Plant Journal 68, 977-986.

Van Etten, J.L. and Dunigan, DD. (2012). Chloroviruses: not your everyday plant virus.  Trends Plant Sci.  17, 1-8.  (cover photo).

Wulfmeyer, T., C. Polzer, G. Hiepler, K. Hamacher, R. Shoeman, D.D. Dunigan, J.L. Van Etten, M. Lolicato, A. Moroni, G. Thiel, and T. Meckel. (2012). Structural organization of DNA in chlorella viruses. PloS One 7, e30133.

Charlop-Powers, Z., J. Jakoncic, J. Gurnon, J.L. Van Etten, and M.M. Zhou. (2012). Paramecium bursaria chlorella virus 1 encodes a polyamine acetyltransferase. J. Biol. Chem. 287, 9547-9551. 

Blanc, G., Agarkova, I., Grinwood, J., Kuo, A., Brueggeman, A., Dunigan, DD., Gurnon, J., Ladunga, I., Lindquist, E., Lucas, S., Pangilinan, J., Proschold, T., Salamov, A., Schumtz, J., Weeks, D., Yamada, T., Claverie, JM., Grigoriev, I.V., Van Etten, J.L. (2012). The genome of the polar eukaryotic microalga Coccomyxa subellipsoidea reveals traits of cold adaptation. Genome Biology 13, R39.

Hamacher, K., Greiner, T., Ogata, H., Van Etten, J.L., Gebhardt, M., Villarreal, L.P., Cosentino, C., Moroni, A., and Theil, G. (2012).  Phycodnavirus potassium ion channel proteins question the virus molecular piracy hypothesis. PLoS One 7, e38826.           

Dunigan, D.D., Cerny, R.L., Bauman, A.T., Roach, J.C., Lane, L.C., Agarkova, I.V., Wulser, K., Yanai-Balser, G.M., Gurnon, J.R., Vitek, J.C., Kronschnabel, B.J., Jeannard, A., Blanc, G., Upton, C., Duncan, G.A., McClung, O.W., Ma, F., Van Etten, J.L. (2012).  Paramecium bursaria chlorella virus 1 proteome reveals novel architectural and regulatory features of a giant virus. J. Virol. 86, 8821-8834.. [highlighted article and cover photo]

Gebhardt, M., Henkes, L.M., Tayefeh, S., Hertel, B., Greiner, T., Van Etten, J.L., Baumeister, D., Cosentino, C., Moroni, A., Kast, S.M., and Thiel, G. (2012). Relevance of lysine snorkeling in the outer transmembrane domain of small viral potassium ion channels. Biochemistry 51, 5571-5579.


Carleton College, Minnesota
BA, Biology

University of Illinois, Urbana, IL
MS, Plant Pathology

University of Illinois, Urbana, IL
PhD, Plant Pathology

University of Pavia, Pavia, Italy
Postdoc, Molecular Biology

Professsional Experience

NSF Postdoctoral Fellow, Department of Genetics
University of Pavia, Pavia, Italy, 1965-66

Assistant Professor, Plant Pathology
Univ. of Nebraska, Lincoln, NE, 1966-69

Associate Professor, Plant Pathology
University of Nebraska, Lincoln, NE 1969-74

Professor, Plant Pathology
University of Nebraska, Lincoln, NE, 1974-86

William Allington Professor of Plant Pathology, 1986-93

William Allington Distinguished Professor of Plant Pathology, 1993-present

Coordinator of the UNL Plant Science Initiative, 1997-99

Co-Director of the Nebraska Center for Virology, 2000-present

Membership on Editorial Boards and Government Panels: Editorial Board, Phytopathology, 1974-77

Associate Editor, Experimental Mycology, 1976-96

Editorial Board, Journal of Bacteriology, 1980-85

Editorial Board, Molecular and Cellular Biology, 1981-85

Associate Editor, Virology, 1989-present

Editorial Board, Molecular Plant Pathology, 1999-2003

Co-chairman of Gordon Conference on Fungal Metabolism, 1984

Committee member of NIH study section on Microbial Physiology, 1978, 1981, 1984-87

Committee member of the USDA Grants (Plant Pathology/Weeds) Panel, 1991, 1992

Honors and Professional Affiliations:

Fellow of the American Phytopathological Society, August 1989

Recipient of the University of Nebraska Outstanding Research and Creative Activity Award, 1992

Fellow of the American Association for the Advancement of Science, 1993

Recipient of the Nebraska Sigma Xi outstanding scientist award, 1999

Fellow of the American Academy of Microbiology, 2001

Elected member of the National Academy of Sciences, 2003