scholarly journals Association of L* Protein of Theiler's Murine Encephalomyelitis Virus with Microtubules in Infected Cells

Virology ◽  
2001 ◽  
Vol 289 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Masatsugu Obuchi ◽  
Takato Odagiri ◽  
Kunihiko Asakura ◽  
Yoshiro Ohara
Keyword(s):  
Theiler's Murine Encephalomyelitis Virus ◽  
L Protein ◽  
Theiler’S Murine Encephalomyelitis Virus ◽  
Encephalomyelitis Virus ◽  
Infected Cells

scholarly journals Epitope-Tagged L* Protein of Theiler's Murine Encephalomyelitis Virus Is Expressed in the Central Nervous System in the Acute Phase of Infection

2002 ◽  
Vol 76 (24) ◽  
pp. 13049-13054 ◽  
Author(s):  
Kunihiko Asakura ◽  
Harunobu Murayama ◽  
Toshiki Himeda ◽  
Yoshiro Ohara
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Acute Phase ◽  
Wild Type Virus ◽  
Theiler's Murine Encephalomyelitis Virus ◽  
L Protein ◽  
Theiler’S Murine Encephalomyelitis Virus ◽  
Encephalomyelitis Virus ◽  
The Central Nervous System ◽  
Resistant Strains

ABSTRACT TO subgroup strains of Theiler's murine encephalomyelitis virus (TMEV) synthesize L* protein from an alternative initiation codon. We first demonstrated L* expression in the central nervous system (CNS) of TMEV-infected mice during the acute phase of infection by immunoprecipitation and immunoblotting with anti-L* antibody. In addition, we generated mutant viruses which synthesize FLAG or 3xFLAG epitope-tagged L* protein. With a mutant virus expressing 3xFLAG epitope-tagged L*, designated DA/3xFLAGL*, we investigated L* in the CNS in the acute phase of infection. DA/3xFLAGL* did not change the virus tropism in comparison with wild-type virus, and L* was clearly identified in the CNS in both susceptible and resistant strains of mice. Double immunolabeling studies showed that L* is colocalized with TMEV polyprotein and exclusively expressed in neurons.

scholarly journals Nonstructural Protein L* Species Specificity Supports a Mouse Origin for Vilyuisk Human Encephalitis Virus

2017 ◽  
Vol 91 (14) ◽  
Author(s):  
Melissa Drappier ◽  
Fred R. Opperdoes ◽  
Thomas Michiels
Keyword(s):  
Encephalitis Virus ◽  
Species Specificity ◽  
Functional Assay ◽  
Rnase L ◽  
Theiler's Murine Encephalomyelitis Virus ◽  
L Protein ◽  
Theiler’S Murine Encephalomyelitis Virus ◽  
Human Rnase ◽  
Encephalomyelitis Virus ◽  
Species Specific

ABSTRACT Vilyuisk human encephalitis virus (VHEV) is a picornavirus related to Theiler's murine encephalomyelitis virus (TMEV). VHEV was isolated from human material passaged in mice. Whether this VHEV is of human or mouse origin is therefore unclear. We took advantage of the species-specific activity of the nonstructural L* protein of theiloviruses to track the origin of TMEV isolates. TMEV L* inhibits RNase L, the effector enzyme of the interferon pathway. By using coimmunoprecipitation and functional RNase L assays, the species specificity of RNase L antagonism was tested for L* from mouse (DA) and rat (RTV-1) TMEV strains as well as for VHEV. Coimmunoprecipitation and functional assay data confirmed the species specificity of L* activity and showed that L* from rat strain RTV-1 inhibited rat but not mouse or human RNase L. Next, we showed that the VHEV L* protein was phylogenetically related to L* of mouse viruses and that it failed to inhibit human RNase L but readily antagonized mouse RNase L, unambiguously showing the mouse origin of VHEV. IMPORTANCE Defining the natural host of a virus can be a thorny issue, especially when the virus was isolated only once or when the isolation story is complex. The species Theilovirus includes Theiler's murine encephalomyelitis virus (TMEV), infecting mice and rats, and Saffold virus (SAFV), infecting humans. One TMEV strain, Vilyuisk human encephalitis virus (VHEV), however, was isolated from mice that were inoculated with cerebrospinal fluid of a patient presenting with chronic encephalitis. It is therefore unclear whether VHEV was derived from the human sample or from the inoculated mouse. The L* protein encoded by TMEV inhibits RNase L, a cellular enzyme involved in innate immunity, in a species-specific manner. Using binding and functional assays, we show that this species specificity even allows discrimination between TMEV strains of mouse and of rat origins. The VHEV L* protein clearly inhibited mouse but not human RNase L, indicating that this virus originates from mice.

scholarly journals Expression of L* protein of Theiler's murine encephalomyelitis virus in the chronic phase of infection

2007 ◽  
Vol 88 (8) ◽  
pp. 2268-2274 ◽  
Author(s):  
Kunihiko Asakura ◽  
Harunobu Murayama ◽  
Toshiki Himeda ◽  
Yoshiro Ohara
Keyword(s):  
Chronic Phase ◽  
Mutant Virus ◽  
Zinc Binding ◽  
Binding Motif ◽  
Theiler's Murine Encephalomyelitis Virus ◽  
Flag Epitope ◽  
L Protein ◽  
Theiler’S Murine Encephalomyelitis Virus ◽  
Encephalomyelitis Virus ◽  
Zinc Binding Motif

The DA strain and other members of the TO subgroup of Theiler's murine encephalomyelitis virus synthesize the L* protein from an alternative initiation codon. L* is considered to play a key role in viral persistence and demyelination in susceptible strains of mice, although this hypothesis is still controversial. By using a mutant virus that expresses FLAG epitope-tagged L*, it was demonstrated previously that L* is expressed exclusively in neurons in vivo in the acute phase of infection in the central nervous system (CNS). However, in the mutant virus, the C-H-C-C zinc-binding motif in the leader protein (L) was disrupted by the insertion of the FLAG epitope, resulting in clearance of the virus from the CNS. Therefore, a further two mutant viruses were newly generated, expressing FLAG epitope-tagged L* in which the C-H-C-C zinc-binding motif within L is spared. Both mutant viruses caused persistence and demyelination successfully in spinal cords and enabled us to identify L* immunohistochemically in the demyelinating lesions.

scholarly journals L* Protein of the DA Strain of Theiler’s Murine Encephalomyelitis Virus Is Important for Virus Growth in a Murine Macrophage-Like Cell Line

1998 ◽  
Vol 72 (6) ◽  
pp. 4950-4955 ◽  
Author(s):  
Hisashi Takata ◽  
Masatsugu Obuchi ◽  
Jiro Yamamoto ◽  
Takato Odagiri ◽  
Raymond P. Roos ◽  
...  
Keyword(s):  
Cell Line ◽  
Demyelinating Disease ◽  
Critical Role ◽  
Murine Macrophage ◽  
Coding Region ◽  
Theiler's Murine Encephalomyelitis Virus ◽  
Virus Growth ◽  
L Protein ◽  
Theiler’S Murine Encephalomyelitis Virus ◽  
Encephalomyelitis Virus

ABSTRACT Strain GDVII and other members of the GDVII subgroup of Theiler’s murine encephalomyelitis virus (TMEV) are highly virulent and cause acute polioencephalomyelitis in mice. Neither viral persistence nor demyelination is demonstrated in the few surviving mice. On the other hand, strain DA and other members of the TO subgroup of TMEV are less virulent and establish a persistent infection in the spinal cord, which results in a demyelinating disease. We previously reported that GDVII does not actively replicate in a murine macrophage-like cell line, J774-1, whereas DA strain productively infects these cells (M. Obuchi, Y. Ohara, T. Takegami, T. Murayama, H. Takada, and H. Iizuka, J. Virol. 71:729–733, 1997). In the present study, we used recombinant viruses between these strains of the two subgroups to demonstrate that the DA L coding region of DA strain is important for virus growth in J774-1 cells. Additional experiments with a mutant virus indicate that L* protein, which is synthesized out of frame with the polyprotein from an additional alternative initiation codon in the L coding region of TO subgroup strains, is a key determinant responsible for the cell-type-specific restriction of virus growth. L* protein may play a critical role in the DA-induced restricted demyelinating infection by allowing growth in macrophages, a major site for virus persistence.

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