Previous Article | Next Article 
Journal of Virology, June 2000, p. 5647-5654, Vol. 74, No. 12
0022-538X/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Mouse Hepatitis Virus Replicase Proteins Associate
with Two Distinct Populations of Intracellular Membranes
Amy C.
Sims,1,2
Joachim
Ostermann,3,
and
Mark
R.
Denison1,2,*
Department of Microbiology and
Immunology,1 Department of
Biochemistry,3 and Department of
Pediatrics and the Elizabeth B. Lamb Center for Pediatric
Research,2 Vanderbilt University, Nashville,
Tennessee 37232
Received 2 December 1999/Accepted 23 March 2000
The coronavirus replicase gene (gene 1) is translated into two
co-amino-terminal polyproteins that are proteolytically processed to
yield more than 15 mature proteins. Several gene 1 proteins have been
shown to localize at sites of viral RNA synthesis in the infected cell
cytoplasm, notably on late endosomes at early times of infection.
However, both immunofluorescence and electron microscopic studies have
also detected gene 1 proteins at sites distinct from the putative sites
of viral RNA synthesis or virus assembly. In this study, mouse
hepatitis virus (MHV)-infected cells were fractionated and analyzed to
determine if gene 1 proteins segregated to more than one membrane
population. Following differential centrifugation of lysates of
MHV-infected DBT cells, gene 1 proteins as well as the structural N and
M proteins were detected almost exclusively in a high-speed small
membrane pellet. Following fractionation of the small membrane pellet
on an iodixanol density gradient, the gene 1 proteins p28 and helicase
cofractionated with dense membranes (1.12 to 1.13 g/ml) that also
contained peak concentrations of N. In contrast, p65 and p1a-22 were
detected in a distinct population of less dense membranes (1.05 to 1.09 g/ml). Viral RNA was detected in membrane fractions containing
helicase, p28, and N but not in the fractions containing p65 and
p1a-22. LAMP-1, a marker for late endosomes and lysosomes, was detected
in both membrane populations. These results demonstrate that multiple gene 1 proteins segregate into two biochemically distinct but tightly
associated membrane populations and that only one of these populations
appears to be a site for viral RNA synthesis. The results further
suggest that p28 is a component of the viral replication complex
whereas the gene 1 proteins p1a-22 and p65 may serve roles during
infection that are distinct from viral RNA transcription or replication.
*
Corresponding author. Mailing address: Department of
Pediatrics, Vanderbilt University Medical Center, D7235 MCN, Nashville, TN 37232-2581. Phone: (615) 343-9881. Fax: (615) 343-9723. E-mail: mark.denison{at}mcmail.vanderbilt.edu.

Present address: EMBL, 69012 Heidelberg,
Germany.
Journal of Virology, June 2000, p. 5647-5654, Vol. 74, No. 12
0022-538X/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Seo, J.-Y., Britt, W. J.
(2008). Multimerization of Tegument Protein pp28 within the Assembly Compartment Is Required for Cytoplasmic Envelopment of Human Cytomegalovirus. J. Virol.
82: 6272-6287
[Abstract]
[Full Text]
-
Zust, R., Miller, T. B., Goebel, S. J., Thiel, V., Masters, P. S.
(2008). Genetic Interactions between an Essential 3' cis-Acting RNA Pseudoknot, Replicase Gene Products, and the Extreme 3' End of the Mouse Coronavirus Genome. J. Virol.
82: 1214-1228
[Abstract]
[Full Text]
-
Sparks, J. S., Lu, X., Denison, M. R.
(2007). Genetic Analysis of Murine Hepatitis Virus nsp4 in Virus Replication. J. Virol.
81: 12554-12563
[Abstract]
[Full Text]
-
Zhou, H., Perlman, S.
(2007). Mouse Hepatitis Virus Does Not Induce Beta Interferon Synthesis and Does Not Inhibit Its Induction by Double-Stranded RNA. J. Virol.
81: 568-574
[Abstract]
[Full Text]
-
Graham, R. L., Denison, M. R.
(2006). Replication of Murine Hepatitis Virus Is Regulated by Papain-Like Proteinase 1 Processing of Nonstructural Proteins 1, 2, and 3. J. Virol.
80: 11610-11620
[Abstract]
[Full Text]
-
Seo, J.-Y., Britt, W. J.
(2006). Sequence Requirements for Localization of Human Cytomegalovirus Tegument Protein pp28 to the Virus Assembly Compartment and for Assembly of Infectious Virus.. J. Virol.
80: 5611-5626
[Abstract]
[Full Text]
-
Galan, C., Enjuanes, L., Almazan, F.
(2005). A Point Mutation within the Replicase Gene Differentially Affects Coronavirus Genome versus Minigenome Replication. J. Virol.
79: 15016-15026
[Abstract]
[Full Text]
-
Graham, R. L., Sims, A. C., Brockway, S. M., Baric, R. S., Denison, M. R.
(2005). The nsp2 Replicase Proteins of Murine Hepatitis Virus and Severe Acute Respiratory Syndrome Coronavirus Are Dispensable for Viral Replication. J. Virol.
79: 13399-13411
[Abstract]
[Full Text]
-
Schelle, B., Karl, N., Ludewig, B., Siddell, S. G., Thiel, V.
(2005). Selective Replication of Coronavirus Genomes That Express Nucleocapsid Protein. J. Virol.
79: 6620-6630
[Abstract]
[Full Text]
-
Brockway, S. M., Lu, X. T., Peters, T. R., Dermody, T. S., Denison, M. R.
(2004). Intracellular Localization and Protein Interactions of the Gene 1 Protein p28 during Mouse Hepatitis Virus Replication. J. Virol.
78: 11551-11562
[Abstract]
[Full Text]
-
Chen, C.-J., Sugiyama, K., Kubo, H., Huang, C., Makino, S.
(2004). Murine Coronavirus Nonstructural Protein p28 Arrests Cell Cycle in G0/G1 Phase. J. Virol.
78: 10410-10419
[Abstract]
[Full Text]
-
Denison, M. R., Yount, B., Brockway, S. M., Graham, R. L., Sims, A. C., Lu, X., Baric, R. S.
(2004). Cleavage between Replicase Proteins p28 and p65 of Mouse Hepatitis Virus Is Not Required for Virus Replication. J. Virol.
78: 5957-5965
[Abstract]
[Full Text]
-
Prentice, E., Jerome, W. G., Yoshimori, T., Mizushima, N., Denison, M. R.
(2004). Coronavirus Replication Complex Formation Utilizes Components of Cellular Autophagy. J. Biol. Chem.
279: 10136-10141
[Abstract]
[Full Text]
-
Ebert, D. H., Kopecky-Bromberg, S. A., Dermody, T. S.
(2004). Cathepsin B Is Inhibited in Mutant Cells Selected during Persistent Reovirus Infection. J. Biol. Chem.
279: 3837-3851
[Abstract]
[Full Text]
-
Brockway, S. M., Clay, C. T., Lu, X. T., Denison, M. R.
(2003). Characterization of the Expression, Intracellular Localization, and Replication Complex Association of the Putative Mouse Hepatitis Virus RNA-Dependent RNA Polymerase. J. Virol.
77: 10515-10527
[Abstract]
[Full Text]
-
Yount, B., Denison, M. R., Weiss, S. R., Baric, R. S.
(2002). Systematic Assembly of a Full-Length Infectious cDNA of Mouse Hepatitis Virus Strain A59. J. Virol.
76: 11065-11078
[Abstract]
[Full Text]
-
Ng, L. F. P., Liu, D. X.
(2002). Membrane Association and Dimerization of a Cysteine-Rich, 16-Kilodalton Polypeptide Released from the C-Terminal Region of the Coronavirus Infectious Bronchitis Virus 1a Polyprotein. J. Virol.
76: 6257-6267
[Abstract]
[Full Text]
-
Nanda, S. K., Leibowitz, J. L.
(2001). Mitochondrial Aconitase Binds to the 3' Untranslated Region of the Mouse Hepatitis Virus Genome. J. Virol.
75: 3352-3362
[Abstract]
[Full Text]