1. We have been using mammalian reoviruses (MRV) and avian reoviruses (ARV) as models for understanding how multiple proteins and nucleic acids recognize each other and interact to generate a functionally active macromolecular complex. We have generated and characterized sets of assembly-defective temperature-sensitive (ts) mutants. These mutants, as well as normal wild-type virus, are being examined by biologic, molecular genetic, and mass spectroscopic methods to better understand virus assembly and disassembly. We also are conducting a variety of functional assays of viral RNA-dependent RNA polymerase, an enzyme unique to virtually all RNA viruses but absent from host cells to aid development of therapeutic strategies to combat RNA viruses.
2. Viruses are the primary cause of infectious gastroenteritis and, importantly, many cases are caused by unknown viruses. Thus, we also seek to discover and molecularly characterize novel viral agents. We have discovered two such potentially new viruses that are currently under molecular analyses to allow comparison to other known agents and to establish diagnostic and therapeutic strategies.
3. Recent work by Dr. Patrick Lee at the University of Calgary has shown that reovirus may have potential as an anti-cancer agent. To be used therapeutically, it will be necessary to grow industrial-sized quantities, and, because of dangers associated with bovine spongiform encephalopathies ("mad cow disease"), preferably in growth media devoid of animal products. In collaboration with Dr. Mike Butler in the Department of Microbiology at our University, we have been experimenting with growing industrial-sized amounts of virus in serum-free media.
4. There is increased concern about the safety of available drinking water and environmental consequences of contaminated waste water and water runoff. In collaboration with Dr. Jan Oleszkiewicz, of the Department of Engineering, we are using the MRV as “biomarkers” to test the efficiency of various treatments during disinfection of water and wastewater.
5. There are numerous strategies to combat infections by pathogenic organisms, including vaccination and anti-virals. We are testing the capacities of various anti-viral compounds to attenuate replication of reoviruses and influenza virus. We also are interested in selecting anti-viral-resistant mutants of each virus type to better understand molecular mechanisms of antiviral effects and resistance mechanisms.
6. Viruses induce profound changes in cells at both the genomic and protein levels. We are using state-of-the-art mass spectrometry-based, and shRNAi-based, Systems Biology approaches to understand the effects induced in the total cellular Proteome (entire protein repertoire, including all modifications) after various cells are infected with either reoviruses or influenza viruses.

1. Xu, W., A.T. Tran, M.K. Patrick, and K.M. Coombs . (2005). Assignment of avian reovirus temperature-sensitive mutants in recombination groups B, C, and D to genome segments. Virology 338: 227-235. [Cover illustration].

2. Hadžisejdic, I. , K. Cheng, J. Wilkins, W. Ens, and K.M. Coombs . (2006). High-resolution mass spectrometric mapping of reovirus digestion. Rapid Comm. Mass Spectrom. 20: 438-446.
3. Mendez, I.I., S.G. Weiner, Y.-M. She, M. Yeager, and K.M. Coombs . (2008). Conformational changes accompany activation of reovirus RNA dependent RNA transcription. J. Struct. Biol. [doi:10.1016/j.jsb.2008.01.006] In Press.
4. Tran, A.T., W. Xu, T. Racine, D.A. Silaghi, and K.M. Coombs . (2008). Assignment of avian reovirus temperature-sensitive mutants in recombination groups E, F, and G to genome segments. Virology [doi:10.1016/j.virol.2008.02.010] In Press.
5. Ao, Z., A. Patel, K. Tran, X. He, K. Fowke, K. Coombs , D. Kobasa, G. Kobinger, and X. Yao. (2008). Characterization of a trypsin-dependent avian influenza H5N1-pseudotyped HIV vector system for high throughput screening of inhibitory molecules. Antiviral Research. [doi:10.1016/j.antiviral.2008.02.001] In Press.
6. Yin, P., N.D. Keirstead, T.J. Broering, M.M. Arnold, J.S.L. Parker, M.L. Nibert, and K.M. Coombs. (2004). Comparisons of the M1 genome segments and encoded µ2 proteins of different reovirus isolates. Virol. J. 1:6. (online journal address: http://www.virologyj.com/content/1/1/6 )
7. Xu, W., M.K. Patrick, P.R. Hazelton, and K.M. Coombs. (2004). Avian reovirus temperature-sensitive mutant tsA12 has a lesion in the major core protein FA and is defective in assembly. J. Virol. 78:11142-11151. PMID: 15452234
8. Robertson, C.R., L.L. Hermann, and K.M. Coombs. (2004). Mycophenolic acid inhibits replication of avian reovirus. Antiviral Res. 64: 55-61. PMID: 15451179
9. Hermann, L.L. and K.M. Coombs. (2004). Inhibition of reovirus by mycophenolic acid is associated with the M1 genome segment. J. Virol. 78:6171-6179. PMID: 15163710
10. Mendez, I.I., Y.-M. She, W. Ens, and K.M. Coombs (2003) Digestion pattern of reovirus outer capsid protein sigma3 determined by mass spectrometry. Virology 311: 289-304. PMID: 12876456
11. Swanson, M.I., Y.-M. She, W. Ens, E.G. Brown, and K.M. Coombs.(2002). Mammalian reovirus core protein mu2 initiates at the first startcodon and is acetylated. Rapid Comm. Mass Spectrom. 16:2317-
    2324. PMID: 12478577
12. O'Hara, D., M. Patrick, D. Cepica, K.M. Coombs, and R. Duncan. (2001). Avian reovirus major m-class outer capsid protein influences efficiency of productive macrophage infection in a virus strain-specific manner. J. Virol. 75:5027-5035. PMID 11333882
13. Patrick, M., R. Duncan, and K.M. Coombs. (2001). Generation and genetic characterization of avian reovirus temperature-sensitive mutants. Virology 284:113-122. PMID 11352672
14. Butler, M., A. Burgener, M. Patrick, M. Berry, D. Moffatt, N. Huzel, N. Barnabé, and K. Coombs. (2000). Application of a serum-free medium or the growth of Vero cells and the production of reovirus. Biotech. Prog. 16:854-858. PMID 11027181
15. Becker MM, Goral MI, Hazelton PR, Baer GS, Rodgers SE, Brown EG, Coombs KM, Dermody TS. Reovirus sigmaNS protein is required for nucleation of viral assembly complexes and formation of viral inclusions.J Virol. 2001 Feb;75(3):1459-75. PMID: 11152519
16. Mendez, I.I., Hermann, L.L., Hazelton, P.R. and Coombs, K.M. Coombs. A comparative analysis of Freon substitutes in the purification of reovirus and calicivirus. J. Virol. Meth. 90:59-67 (2000). PMID: 11011081
17. Hazelton, P.R., and Coombs, K.M. The reovirus mutant tsA279 L2 gene is associated with generation of a spike-less core particle: Implications for capsid assembly. J. Virol. 73:2298-2308 (1999). PMID: 9971813 
18. Berry, J.M., Bérnaby,N., Coombs, K.M., and Butler, M. Production of reovirus type-1 and type-3 from Vero cells grown on solid and macroporous microcarriers. Biotech. Bioeng. 62:12-19 (1999). PMID: 10099508
19. Coombs, K.M. Temperature-sensitive mutants of reovirus. Curr. Topic Microbiol. Immunol. 233:69-107 (1998).
20. Keirstead, N.D., and Combs K.M. Absence of superinfection exclusion during asynchronous reovirus infections of mouse, monkey, and human cell lines. Virus Res. 54:225-235 (1998). PMID: 9696130
21. Coombs, K.M. Stoichiometry of reovirus structural proteins in virus, ISVP, and core particles. Virology 243:218-228 (1998). PMID: 9527931 
22. Shing, M., and Coombs, K.M. Assembly of the reovirus outer capsid requires mu 1/sigma 3 interactions which are prevented by misfolded sigma 3 protein in reovirus temperature-sensitive mutant tsG453. Virus Res. 46:19-29 (1996). PMID: 9029774
23. Nibert, M.L., Margraf, R.L., and Coombs, K.M. Non-random segregation of parental alleles in reovirus reassortants. J. Virol. 70:7295-7300 (1996). PMID: 8794386
24. Coombs, K.M. Identification and characterization of a dsRNA- reovirus temperature-sensitive mutant defective in minor core protein mu 2. J. Virol. 70:4237-4245 (1996). PMID: 8676444
25. Yin, P., Cheang, M, and Coombs, K.M. The M1 gene is associated with differences in the temperature optimum of the transcriptase activity in reovirus core particles. J. Virol. 70:1223-1227 (1996). PMID: 8551584 
26. Hazelton, P.R., and Coombs, K.M. The reovirus mutant tsA279 has temperature-sensitive lesions in the M2 and L2 genes: The M2 gene is associated with reduced viral protein production and blockade in transmembrane transport. Virology 207:46-58 (1995). PMID: 7871752
27. Coombs, K.M., Mak, S.-C., and Cox, L. Studies of the major reovirus core protein sigma 2: Reversion of the assembly-defective mutant tsC447 is an intragenic process and involves back mutation of Asp-383 to Asn. J. Virol. 68:177-186 (1994). PMID: 8254727 

Coombs Lab members, Summer of 2007
	Standing: Lou, Kola, Mark, Scott, Jieyuan, Peter; Front row: Shelly, Alicia, Alyson, Thais, Wanhong

Laboratory Members: