Gary Blissard
Scientist, Vice President for Research
Office/Lab: Room 201/202
Contact: gwb1@cornell.edu / 607-254-1366
Affiliations:
Adjunct Professor, Cornell University’s
Department of Microbiology & Immunology and Department of Entomology
Graduate Field: Comparative Biomedical Sciences, Entomology
Research Summary
Position available:
- Postdoc in Viral Envelope Protein Structure-Function Studies
(1 available)
Studies in our laboratory are focused on understanding the biology and pathology of viral infections. We study a group of viruses called “baculoviruses” which are large DNA viruses that have been used for biological control of insect pest species. In addition, baculoviruses have been developed as powerful gene expression systems for producing eukaryotic proteins in both research and industrial applications. More recently, baculoviruses have been examined as potential vectors for human gene therapy. A major thrust of our work is focused on basic studies of the glycoproteins found in the envelopes of baculoviruses, and the roles of specific envelope proteins in viral attachment, entry, and exit. We also have interests in the evolutionary origins of viral envelope proteins and the acquisition of envelope protein genes by viruses. Another major research focus in our lab is the study of viral gene expression. We are using model baculovirus promoters, a recently developed genetic knockout system, and a viral microarray to examine the regulation of early and late phases of viral gene expression.
Baculoviruses are large DNA viruses that infect and are highly pathogenic to a number of very important insect pest species.
Because they represent a highly host-specific and thus environmentally friendly alternative to chemical methods of insect control, baculoviruses will likely comprise an important component of future strategies for biological control in both agriculture and forestry. Baculoviruses have also been developed and used extensively in research, serving as invaluable expression vectors for high level production of recombinant proteins. In addition, baculoviruses serve as convenient model systems for studies of virus entry and exit, transcriptional regulation, DNA replication, and other host-pathogen interactions.
Viral entry and exit. To enter a host cell, the envelope of the baculovirus must fuse with the host plasma membrane, releasing the nucleocapsid (which carries the viral genome) into the cell. Membrane fusion occurs at a low pH, during a process known as receptor-mediated endocytosis. In early studies, we found that a viral envelope glycoprotein known as GP64, was necessary and sufficient for the low pH-activated membrane fusion activity that occurs during endocytosis. We also demonstrated that the GP64 protein serves as a viral attachment protein at the cell surface (at the first step of cellular entry). Our studies also showed that the GP64 protein is involved in virus assembly during the final phase of the infection cycle, when progeny virus particles bud from the cell surface. Current studies are focused on understanding how the structure and organization of this important protein facilitate these diverse and essential functions. For these studies, we are using a variety of physical, biochemical, genetic, and molecular techniques to identify and define specific functional domains of the GP64 protein. Of particular importance, we recently developed a GP64 knockout virus, and a system for replacing the essential wild type gp64 gene with mutant forms of gp64. These powerful molecular tools are allowing us to perform detailed studies of the roles of this envelope protein, and the functions of specific protein domains - all in the context of the viral infection, as well as with infected host animals (insects).
Viral gene expression. We are also examining the regulation of baculovirus gene expression. The large genomes of baculoviruses may encode over 150 genes and these genes are expressed in two major phases, early and late. Early phase genes are transcribed by the host cell’s RNA polymerase II, whereas late phase genes are transcribed by a viral encoded have focused on the identification of sequences regulating early and late viral transcription, and on host and viral regulatory proteins that interact with viral regulatory sequences. We are currently using a genetic knockout system to examine the roles of specific late expression factor (LEF) genes in regulating late gene transcription. A major goal of these studies is to more broadly understand the regulation of viral gene expression and to develop regulatory paradigms within this virus family. By studying DNA sequence motifs and the host and viral proteins required for the activation and modulation of baculovirus gene expression, we are developing a better understanding of the intricate mechanisms regulating gene expression from these large viral genomes.
Publications
Lung, O., G. W. Blissard. 2005. A Cellular Drosophila melanogaster Protein with Similarity to Baculovirus F Envelope Fusion Proteins. Journal of Virology 79: 7979-7989
Zhang, S. X. X., Y. Han, G. W. Blissard. 2003. Palmitoylation of the Autographa californica multicapsid nucleopolyhedrovirus envelope glycoprotein GP64: mapping, functional studies, and lipid rafts. Journal of Virology 77: 6265-6273
Lung, O. Y., M. Cruz Alvarez, G. W. Blissard. 2003. Ac23, an envelope fusion protein homolog in the baculovirus Autographa californica multicapsid nucleopolyhedrovirus, is a viral pathogenicity factor. Journal of Virology 77: 328-339
Lin, G., G. W. Blissard. 2002. Analysis of an Autographa californica nucleopolyhedrovirus lef-11 knockout: LEF-11 is essential for viral DNA replication. Journal of Virology 76: 2770-2779
Lin, G., G. W. Blissard. 2002. Analysis of an Autographa californica Multicapsid Nucleopolyhedrovirus lef-6-Null Virus: LEF-6 is not essential for viral replication but appears to accelerate late gene transcription. Journal of Virology 76: 5503-5514
Lung, O., M. Westenberg, J. M. Vlak, D. Zuidema, G. W. Blissard. 2002. Pseudotyping Autographa californica Multicapsid Nucleopolyhedrovirus (AcMNPV): F proteins from group II NPVs are functionally analogous to AcMNPV GP64. Journal of Virology 76: 5729-5736
Lin, G., J. M. Slack, G. W. Blissard. 2001. Expression and localization of LEF-11 in Autographa californica nucleopolyhedrovirus infected Sf9 cells. Journal of General Virology 82: 2289-2294
Mangor, J. T., S. A. Monsma, M. C. Johnson, G. W. Blissard. 2001. A GP64null baculovirus pseudotyped with Vesicular Stomatitis Virus G protein. Journal of Virology 75: 2544-2556
Slack, J. M., G. W. Blissard. 2001. Measurement of membrane fusion activity from viral membrane fusion proteins based on a fusion-dependent promoter induction system in insect cells. Journal of General Virology 82: 2519-2529
IJkel, W. F. J., M. Westenberg, R. W. Goldbach, G. W. Blissard, J. M. Vlak, D. Zuidema. 2000. A Novel Baculovirus Envelope Fusion Protein with a Proprotein Convertase Cleavage Site. Virology 275: 30-41
Plonsky, I., M. S. Cho, A. G. P. Oomens, G. W. Blissard, J. Zimmerberg. 1999. An Analysis of the Role of the Target Membrane on the Gp64-induced Fusion Pore. Virology 253: 65-76
Oomens, A. G. P., G. W. Blissard. 1999. Requirement for GP64 to Drive Efficient Budding of Autographa californica Multicapsid Nucleopolyhedrovirus. Virology 254: 297-314
Kingsley, D. H., A. Behbahani, A. Rashtian, G. W. Blissard, J. Zimmerberg. 1999. A Discrete Stage of Baculovirus GP64-mediated Membrane Fusion. Molecular Biology of the Cell 10: 4191-4200
Hefferon, K. L., A. G. Oomens, S. A. Monsma, C. M. Finnerty, G. W. Blissard. 1999. Host Cell Receptor Binding by Baculovirus GP64 and Kinetics of Virion Entry. Virology 258: 455-468
Chang, M. J., J. Kuzio, G. W. Blissard. 1999. Modulation of Translational Efficiency by Contextual Nucleotides Flanking a Baculovirus Initiator AUG Codon. Virology 259: 369-383
Lab Members
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