Mechanism of interferon action: alpha and gamma interferons differentially affect mRNA levels of the catalytic subunit of protein kinase A and protein Mx in human cells.
Treatment of human HeLa and amnion U cells with gamma interferon (IFN-gamma), either alone or in combination with alpha interferon (IFN-alpha), reduced the steady-state level of mRNA encoding the catalytic (C) subunit of protein kinase A (PKA) as measured by Northern gel-blot (RNA) analysis. In addition, IFN-gamma treatment increased the ratio of C alpha to C alpha 2 (the two splice-site variants of PKA C alpha subunit mRNA produced in HeLa cells) as measured by a polymerase chain reaction assay. IFN-gamma greatly reduced the amount of a novel splice-site variant of PKA, C alpha 2, which retains introns G and H, relative to the amount of C alpha, which lacks introns G and H. IFN-alpha treatment in combination with IFN-gamma did not further reduce the level of PKA C alpha transcripts beyond that of IFN-gamma alone, as measured by Northern blots; however, IFN-alpha in combination with IFN-gamma did cause a synergistic increase in the level of human Mx transcripts.
Thomas
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DC
Department of Biological Sciences, University of California, Santa Barbara 93106-9610.
Samuel
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CE
D001483:Base Sequence; D015152:Blotting, Northern; D002384:Catalysis; D002460:Cell Line; D004279:DNA, Viral; D019204:GTP-Binding Proteins; D006367:HeLa Cells; D006801:Humans; D016898:Interferon-alpha / Q000378:metabolism*; D007371:Interferon-gamma / Q000378:metabolism*; D008969:Molecular Sequence Data; D064547:Myxovirus Resistance Proteins; D016133:Polymerase Chain Reaction; D011494:Protein Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
D004279:DNA, Viral; D016898:Interferon-alpha; D064547:Myxovirus Resistance Proteins; D011506:Proteins; D012333:RNA, Messenger; D007371:Interferon-gamma; D011494:Protein Kinases; D019204:GTP-Binding Proteins