Isolation of cDNA clones for the interferon-induced 67,000-dalton protein: direct induction of a family of mRNAs by human interferon-alpha and interferon-gamma.
A partial cDNA clone for the interferon (IFN)-induced 67,000-dalton (67K) protein was isolated by immunological screening and used as a probe to study the expression of mRNAs encoding this protein. Northern blot analyses of RNA from IFN-treated GM2767 cells revealed the presence of two major 67K-specific RNA species, 2.7 and 4.3 kb in length, and two minor RNA species, 5.7 and 7.2 kb long. All of these 67K-specific RNAs were polyadenylated. Multiple 67K-specific mRNAs were observed to be induced in several cell lines. IFN-gamma was more effective at inducing these mRNAs than was IFN-alpha. In IFN-alpha-treated GM2767 cells, the 67K-specific mRNAs were detectable 6 h following IFN treatment, but not 12, 18, or 24 h following treatment. In IFN-gamma-treated cells, these mRNAs were detectable 6 h after treatment and continued to be present 24 h after treatment. The induction of the 67K-specific mRNAs in GM2767 cells did not require protein synthesis as the RNAs were induced by IFN-alpha or IFN-gamma in the presence of cycloheximide (CHX, 50 micrograms/ml). Treatment of cells with the combination of CHX and IFN-alpha mediated an enhanced accumulation of the 67K-specific mRNAs, suggesting that ongoing protein synthesis may downregulate the induction or accumulation of the IFN-alpha-induced 67K-specific mRNAs. Western blot analysis employing a monoclonal antibody to the 67K protein revealed that several distinctly sized but immunologically related proteins were induced in IFN-treated cells.
Margolis-Nunno
H
H
New York Blood Center, NY 10021.
Rubin
B Y
BY
Anderson
S L
SL
Lunn
R M
RM
Roy
S N
SN
Dizik
M
M
Sen
G C
GC
D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D004247:DNA / Q000235:genetics*; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D007372:Interferons / Q000494:pharmacology*; D007700:Kinetics; D008970:Molecular Weight; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*
D007370:Interferon Type I; D011506:Proteins; D012333:RNA, Messenger; D007371:Interferon-gamma; D004247:DNA; D007372:Interferons; D003513:Cycloheximide