Disease relevance of RPVgp4

• Measles-virus proteins in the brain tissue of patients with subacute sclerosing panencephalitis: absence of the M protein [1].
• Here, extant MV mutants and chimeras were used to determine the role of M protein in the transport of viral glycoproteins and release of progeny virions in polarized epithelial CaCo2 cells [2].
• These results offer concrete evidence that the M protein of an SSPE virus is functionally different from that of its progenitor acute measles virus [3].
• Conversely, the Nagahata M protein can bind to the Biken viral nucleocapsids, although this association is not as stable at physiological salt concentration [3].
• The M protein occurs in the infected cells as two distinct bands, and, as in the case of Sendai virus, one of these two M protein bands represents a phosphorylated form of the other [4].

High impact information on RPVgp4

• The Nagahata viral M protein is associated with the intracellular viral nucleocapsids and the plasma membrane, whereas the Biken viral M protein is localized mainly in the cytosol [3].
• The results suggest that in patients with SSPE there is either diminished synthesis of M, or it is not recognized normally by the immune system, and that an abnormality in M protein is involved in the pathogenesis of SSPE [5].
• P64S and E89K substitutions were responsible for the ability of the M protein to make virus grow efficiently in Vero cells, while the first half of the Edmonston L gene was important for better replication [6].
• The long 3' UTR of the M mRNA was shown to have the ability to increase the M protein production, promoting virus replication [7].
• Whereas the M protein appears dispensable altogether, partial preservation of F-protein function and H-protein function seems to be required, presumably to allow local cell fusion [8].

Biological context of RPVgp4

• The interaction of paramyxovirus M protein with actin and the subsequent production of antibodies to new antigenic sites may serve as a model for one of the mechanisms of virus-induced autoimmunity [9].
• The binding site for M protein on actin is different from the binding sites for antiactin antibodies [9].
• In SSPE brain, the viral M-protein defect is not a deletion of the M gene, but rather a block in gene expression [10].
• M protein was not produced in the same cells even though the M cistron could direct M protein synthesis in vitro once excised from the upstream P cistron [11].
• The M protein amino acid sequence was compared to the homologous proteins from other members of the Paramyxoviridae family [12].

Anatomical context of RPVgp4

• Antibodies to the M protein, as well as to other proteins, were detected (by immunoprecipitation) in the serum and cerebrospinal fluid of the patient [13].
• M protein instability and lack of H protein processing associated with nonproductive persistent infection of HeLa cells by measles virus [14].
• In addition, the M protein was detected occasionally in the nucleus of neurons and reactive astrocytes [15].
• All these results suggest that SSPE virus isolated with a lymphoid cell line is similar in neuropathogenicity to that isolated with a nonlymphoid cell lines, irrespective of differences in the molecular mechanism of M protein defectiveness [16].
• Unexpectedly, plasmid-encoded M protein was rarely found to accumulate at surface membranes [17].

Associations of RPVgp4 with chemical compounds

• As a result, the Biken virus M protein loses conformation-specific epitopes that are conserved in the M proteins of Nagahata and Edmonston strain acute measles viruses [18].
• The synthesis of various viral mRNAs in the presence of actinomycin D decreased gradually at similar rates after a shift to 39 degrees C. No specific disappearance of the mRNA coding for the M protein was observed when viral RNAs isolated from the infected cells were compared before and after a shift up by Northern blot analysis [19].
• The molecular weight (38,670), deduced from the amino acid sequence, is in agreement with the molecular weight of the viral M protein estimated by polyacrylamide gel electrophoresis (39-40 kDa) [20].

Other interactions of RPVgp4

• However, limited proteolysis has shown that this protein is not a phosphorylated form of the M protein, but appears related to the P protein of measles virus [21].
• The synthesis of H, N and possibly F protein was seen in both lytic and persistent infections, but the synthesis of M protein was only detected in the lytic infection [22].

Analytical, diagnostic and therapeutic context of RPVgp4

• This phenomenon was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total cytoplasmic lysates and immunoprecipitation with monoclonal antibody against the M protein in short-time labeling experiments [19].
• The sequences of the human parainfluenza virus type 3 (PIV3) matrix (M) mRNA [1150 nucleotides exclusive of poly(A)] and predicted M protein (353 amino acids) were determined by sequence analysis of cloned cDNA and viral genomic RNA [23].
• In situ hybridization with a tritiated cloned cDNA probe was used to search for RNA encoding M protein [24].
• In the culture SSPE virus isolate, the results were the same until the infected cells were examined by electron microscopy and a very limited expression of M protein was revealed [24].
• By immunocytochemistry using the anti-M monospecific serum, M protein was detected in all of the virus-infected cells regardless of cell-free virus production [25].

References