Purification and characterization of a human Mx protein.
Human interferon-beta (IFN-beta) induces in human embryonic foreskin fibroblasts a cytoplasmic protein with antigenic similarities to mouse Mx protein, a nuclear protein implicated in inhibition of influenza virus replication. The human protein was purified to virtual homogeneity by immunoaffinity chromatography using a monoclonal antibody to mouse Mx protein. The purified protein has an apparent Mr of 78,000 and displays a strong tendency to self-aggregate. It can be resolved on two-dimensional gels into four spots with pIs between 6.0 and 6.2, each of which reacts with antibodies to mouse Mx protein. The partial amino-terminal sequence was determined for the affinity-purified protein. Cytoplasmic microinjection of the affinity-purified protein does not lead to efficient protection against infection with influenza virus. Cytoplasmic microinjection of the monoclonal Mx antibody, which increases suceptibility of IFN-treated mouse Mx cells to influenza virus, does not alter the viral susceptibility of IFN-treated human cells. These results suggest that, unlike the mouse Mx protein, the human Mx protein studied in this communication may not be sufficient to confer to cells a high degree of protection against influenza virus.
Weitz
G
G
Laboratory of Viral and Molecular Pathogenesis, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892.
Bekisz
J
J
Zoon
K
K
Arnheiter
H
H
D000595:Amino Acid Sequence; D000906:Antibodies / Q000008:administration & dosage; D000998:Antiviral Agents / Q000302:isolation & purification / Q000502:physiology; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins; D006801:Humans; D009980:Influenza A virus / Q000502:physiology; D007370:Interferon Type I / Q000494:pharmacology; D008845:Microinjections; D008969:Molecular Sequence Data; D008970:Molecular Weight; D064547:Myxovirus Resistance Proteins; D011506:Proteins / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000502:physiology; D014779:Virus Replication
D000906:Antibodies; D000998:Antiviral Agents; D007370:Interferon Type I; C579070:Mx1 protein, mouse; D064547:Myxovirus Resistance Proteins; D011506:Proteins; D019204:GTP-Binding Proteins