(2'-5')An-dependent endoribonuclease: enzyme levels are regulated by IFN beta, IFN gamma, and cell culture conditions.
The levels of a (2'-5')An-dependent endonuclease (RNase L) were determined in extracts prepared from murine L cells and Ehrlich ascites tumor (EAT) cells by measuring specific binding of protein to a labeled derivative of (2'-5')An, (2'-5')A3[32P]pCp. RNase L levels were found to depend both on interferon (IFN) treatment and on cell growth conditions. Treatment of murine L cells and EAT cells with 100-2,000 IRU IFN beta or IFN gamma resulted in a similar 2-4-fold increase in the levels of RNase L when cells were present at low density. The levels of RNase L were also shown to increase 2-3-fold as cells approached saturation density. Serum-starved cells also displayed relatively high levels of RNase L. RNase L levels in cells maintained at high cell density did not change appreciably following treatment with IFN beta or IFN gamma. Regulation of RNase L levels by cell growth conditions as well as by IFN beta or IFN gamma treatment suggests that RNase L may play an important role in regulating the levels of cellular mRNAs as well as acting to degrade viral RNAs.
Floyd-Smith
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Department of Zoology, Arizona State University, Tempe 85287.
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000201:enzymology*; D002460:Cell Line; D046508:Culture Techniques / Q000379:methods; D004722:Endoribonucleases / Q000378:metabolism*; D007370:Interferon Type I / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology*; D007700:Kinetics; D007739:L Cells / Q000201:enzymology; D051379:Mice
D007370:Interferon Type I; D007371:Interferon-gamma; D004722:Endoribonucleases; C031956:2-5A-dependent ribonuclease