Disease relevance of MoV3sS1gp1

• The mammalian reovirus haemagglutinin (sigma 1 protein), which is an outer capsid protein, has been shown to be a major factor in determining virus-host cell interactions [1].
• The identification of sigma 1 residues important for HA and glycophorin binding suggests that tail-forming sequences are exposed on the virion surface, where they interact with carbohydrate residues on the surface of cells [2].
• In this report, we study the reovirus serotype 3 (strain Dearing) sigma 1 protein obtained from various sources: from Escherichia coli expressing sigma 1 protein, from reovirus-infected mouse L cells, and from purified reovirions [3].
• High edge binding of reovirus type 1 to microtubules is correlated with the presence of type 1 or sigma 1 polypeptide [4].
• Analysis of reassortant viruses isolated from an in vitro coinfection with T3 Abney and T1 Lang indicated a strong association of the hepatobiliary disease-producing phenotype with the T3 Abney S1 gene, which encodes the viral cell attachment protein, sigma 1 [5].

Psychiatry related information on MoV3sS1gp1

• Thus, the interaction of reovirus with host defense mechanisms, and the age-dependent restriction of spread of type 3 reovirus from the intestine are mediated by the viral sigma 1 protein [6].

High impact information on MoV3sS1gp1

• Previous studies have identified an area of amino acid sequence similarity shared by the reovirus type 3 cell-attachment protein sigma 1 and an anti-idiotypic/antireceptor monoclonal antibody (mAb) 87.92.6 that mimics reovirus type 3 by attaching to the same cell-surface receptor [7].
• We have shown this monoclonal antibody to be anti-idiotypic in a series of inhibition studies with purified sigma 1 (hemagglutinin) protein and with absorption studies on the idiotypic R1.1 cell line [8].
• The first reading frame has a coding capacity of 455 amino acids, sufficient to account for the known S1 product, protein sigma 1 (42,000 MW) [9].
• Hemolysis was preceded by a major structural transition in ISVPs, characterized by conformational change in micro 1 and elution of fibrous attachment protein sigma 1 [10].
• In contrast to the decrease in infectivity, chymotrypsin treatment of T3D virions leading to generation of ISVPs resulted in a 10-fold increase in their capacity to produce hemagglutination, indicating that a domain of sigma 1 important for binding to sialic acid remains associated with viral particles after sigma 1 cleavage [11].

Chemical compound and disease context of MoV3sS1gp1

• Neuraminidase treatment of L cells substantially decreased the yield of T3D ISVPs in comparison with the yield of virions, indicating that a sigma 1 domain important for binding sialic acid also can mediate attachment of T3D ISVPs to L cells and lead to productive infection [11].

Biological context of MoV3sS1gp1

• A sigma 1 region important for hemagglutination by serotype 3 reovirus strains [2].
• The S1 gene nucleotide sequences of 10 type 3 (T3) reovirus strains were determined and compared with the T3 prototype Dearing strain in order to study sequence diversity in strains of a single reovirus serotype and to learn more about structure-function relationships of the two S1 translation products, sigma 1 and sigma 1s [12].
• It has previously been shown that of all the soluble reovirus-specified proteins present in the infected cell lysate, protein sigma 1 alone possesses the capacity to bind to host cells (P.W.K. Lee, E.C. Hayes, and W.K. Joklik, 1981, Virology 108, 156-163) [13].
• Results obtained with transient and stable expression systems demonstrate that production of serotype 3 sigma 1 and p14 together or individually is not sufficient to change the kinetics of DNA replication in uninfected cells [14].
• Interaction of the sigma 1 protein with serotype-specific receptor molecules located on the surface of target cells determines the tropism and virulence of the virus and mediates viral inhibition of target cell growth [15].

Anatomical context of MoV3sS1gp1

• Exposure of labeled virus to monoclonal antibodies directed against the viral hemagglutinin (sigma 1 protein) inhibited binding, demonstrating that the attachment of reovirus to endothelial cells is mediated by the hemagglutinin for both serotypes [16].
• Hemagglutination (HA) by the mammalian reoviruses is mediated by interactions between the viral sigma 1 protein and sialoglycoproteins on the erythrocyte surface [2].
• Like authentic soluble sigma 1 from reovirus-infected cells, the expressed protein is capable of attaching to mammalian cells (mouse L fibroblasts) in a specific manner and of competing with reovirus particles for cell surface receptors [17].
• The sigma 1 protein determines the extent of spread of reovirus from the gastrointestinal tract of mice [6].

Associations of MoV3sS1gp1 with chemical compounds

• The limited number of sequence differences in the sigma 1 proteins of these seven strains allowed us to identify single unique amino acid residues in each of the HA-negative strains (aspartate 198 in T3C43, leucine 204 in T3C44, and tryptophan 202 in T3C84) that cluster within a discrete region of the sigma 1 tail [2].
• We found that sigma 1 from urea-disrupted reovirus particles was also capable of such specific binding [13].
• Biophysical characterization of purified sigma 1 using column filtration and sucrose gradient sedimentation analysis confirmed the highly asymmetric shape of sigma 1 and allowed us to determine the molecular weight of the native protein to be approximately 132K (a trimer) [18].

Analytical, diagnostic and therapeutic context of MoV3sS1gp1

• Amino acid residues within the sigma 1 protein that were unique to disease-producing T3 strains were identified by comparative sequence analysis [5].
• This analysis has allowed us to investigate molecular epidemiology of T3 reovirus strains and to identify conserved and variable sequence motifs in the S1 translation products, sigma 1 or sigma 1s [12].
• One of the induced proteins had a relative molecular mass (Mr) of approx. 46,000 and corresponded to sigma 1, as shown by immunoprecipitation with goat anti-reovirus antibody and a monoclonal antibody against sigma 1 [19].

References