Brenda G. Hogue
Research
My laboratory has broad interests in the molecular mechanisms of replication and assembly of RNA viruses. We use coronaviruses as our model system. Coronaviruses are a large widespread family of single-stranded, positive-sense enveloped RNA viruses that are medically important respiratory and enteric pathogens of humans and a broad range of domestic animals. The viral genome, ~30 kilobases (kb), is the largest among all RNA viruses. The genome is capped at the 5 end and contains a poly(A) tail. Replication and assembly occur entirely in the cytoplasm where virions assemble and bud at internal membranes of the intermediate compartment, between the endoplasmic reticulum (ER) and cis Golgi. Closely related murine hepatitis (MHV), bovine (BCV) and transmissible gastroenteritis (TGEV) coronaviruses are being studied. We use a system in which virus-like particles (VLPs) are generated when cDNA clones of the viral proteins and defective RNA genomes are co-expressed. A full-length infectious cDNA clone is also used to study the requirements for both assembly and replication directly in the context of the viral genome. An ultimate goal of our studies is to use the information we gain to identify potential targets for antiviral drug development, vaccine design and development of coronaviruses as vectors.
Our assembly studies focus on understanding protein-protein, protein-RNA and protein-lipid interactions that are required for viral assembly. VLPs assemble in a nucleocapsid-independent manner when only the envelope (E) and membrane (M) proteins are coexpressed. Studies are directed at understanding the structure, function and role of E and M in assembly. E is absolutely required for virion assembly and appears to play a major role in determining virion morphology. The protein induces changes in cellular membranes and may play a role in selecting a specific microenvironment within membranes where it induces curvature that facilitates the budding process. M is the most abundant component of the envelope and probably functions like a receptor for nucleocapsid incorporation into virions. We use various microscopic approaches, subcellular fractionation and biochemical analyses to study interactions between the viral proteins and the lipid membrane environment where viruses assemble. We want to understand how the genome is recognized and specifically packaged into virions. We are determining how the packaging signal is recognized and functions as a packaging signal in the context of the large viral genome. We are studying how the nucleocapsid (N) protein interacts with the viral genome.
Replication studies focus on the virus 3 untranslated region (UTR) and its role(s) in viral RNA synthesis. Upon infection the coronavirus genome is presented to the host cell as a very large mRNA. The replicase proteins, including the RNA dependent RNA polymerase, are immediately translated from gene 1 (~ 20 kb) at the 5' end of the genome. Ongoing work is directed at understanding the roles of translation, cis-acting signals in the 3' UTR and host factors in viral RNA replication. Host proteins specifically bind the viral 3' UTR. We have identified one of these proteins as poly(A)-binding protein (PABP). We have also shown that the poly(A) tail is required for viral RNA synthesis. Early steps in coronavirus RNA replication that immediately follow translation of the genome maybe facilitated by interactions between the 3'- and 5'-end of the genome. Coupling between translation and RNA replication of positive-stranded RNA viruses is becoming a widely accepted idea in which there is tremendous interest. We are aggressively pursuing studies in this area.
Selected Publications
White, T.C., Yi, Z. and Hogue, B.G. 2007. Identification of mouse hepatitis coronavirus nucleocapsid protein phosphorylation sites. In Press. Virus Res. (2007), doi:10.1016/j.virusres.2007.02.008.
Ye, Y. and Hogue, B.G. 2007. Role of the mouse hepatitis coronavirus E viroporin protein transmembrane domain in virus assembly. 2007. Epub Jan 17. J. Virol. 81(7):3597–3607.
Ye, Y., Hauns, K.D., Langland, J.O., Jacobs, B.L. and Hogue, B.G. 2007. Mouse Hepatitis Coronavirus A59 nucleocapsid protein is a type I interferon antagonist. 2007. Epub 2006 Dec 20. J Virol. 81(6):2554-63.
Verma, S., Lopez, L.A., Valerie Bednar and Hogue, B.G. 2007. Importance of coronavirus membrane protein penultimate charged residue in virus assembly. 2007. Epub Feb 28; PMID: 17329345. J. Virol. 81(8) Print copy May issue.
Verma, S., Bednar, V., Blount, A., and Hogue, B.G. 2006. Role of coronavirus nucleocapsid protein COOH terminal conserved amino acids in virus assembly. J. Virol. 80:4344-4355.
Lopez, L.A., Jones, A., Arndt, W.D., Hogue, B.G. 2006. Subcellular localization of SARS-CoV structural proteins. The Nidoviruses : The Control of SARS and other Nidovirus Diseases. Perlman and Holmes (editors) Kluwer Academic/Plenum Publishers, London, UK. Adv. Exp. Med. Bio. 581:297-300.
White, T.C. and Hogue, B.G. 2006. Mouse hepatitis coronavirus nucleocapsid phosphorylation. The Nidoviruses : The Control of SARS and other Nidovirus Diseases. Perlman and Holmes (editors) Kluwer Academic/Plenum Publishers, London, UK. Adv. Exp. Med. Bio. 581:157-162.
Ye, Y. and Hogue, B.G. 2006. Role of mouse hepatitis coronavirus envelope protein transmembrane domain. The Nidoviruses : The Control of SARS and other Nidovirus Diseases. Perlman and Holmes (editors) Kluwer Academic/Plenum Publishers, London, UK. Adv. Exp. Med. Bio. 581: 187-192.
Bednar, V., Verma, S., Blount, A. and Hogue, B.G. 2006. Importance of MHV-CoV nucleocapsid protein COOH-termina negative charges. The Nidoviruses : The Control of SARS and other Nidovirus Diseases. Perlman and Holmes (editors) Kluwer Academic/Plenum Publishers, London, UK. Adv. Exp. Med. Bio. 581: 127-132.
Spagnolo JF and Hogue BG. 2001. Requirement of the poly(A) tail in coronavirus genome replication. In The Nidoviruses. Lavi (ed), Kluwer Academic/Plenum Publishers, London, UK. Vol. 494
Cologna R and Hogue BG. 2000. Identification of a bovine coronavirus packaging signal. J. Virol. 74:580-583.
Cologna R, Spagnolo JF and Hogue BG. 2000. Identification of nucleocapsid binding sites within coronavirus-defective genomes. Virology 277:235-249.
Spagnolo JF and Hogue BG. 2000. Host protein interactions with the 3 end of bovine coronavirus RNA and the requirement of the poly(A) tail for coronavirus defective genome replication. J. Virol. 74:5053-5065.