Effect of temperature on ppp(A2′ p)nA binding protein activities in rabbit reticulocyte lysates and other mammalian extracts

Wu, Joseph M.; Eslami, Behruz; Semproni, Anthony R.

doi:10.1016/0006-291x(83)91540-1

Cited by 9 publications

(2 citation statements)

References 23 publications

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“…Oligomers of greater length than the trimer bind to and activate the enzyme approximately equally well. There is limited evidence for tissuespecific differences in oligomer size activation requirements for RNase L (Krause and Silverman, 1993;Wu et al, 1983).…”

Section: Cleawage Specificitymentioning

confidence: 99%

The 2–5 A system: Modulation of viral and cellular processes through acceleration of RNA degradation

Player

Torrence

1998

Pharmacology & Therapeutics

245

195

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The 2-5A system is an RNA degradation pathway that can be induced by the interferons (IFNs). Treatment of cells with IFN activates genes encoding several double-stranded RNA (dsRNA)-dependent synthetases. These enzymes generate 5'-triphosphorylated, 2',5'-phosphodiester-linked oligoadenylates (2-5A) from ATP. The effects of 2-5A in cells are transient since 2-5A is unstable in cells due to the activities of phosphodiesterase and phosphatase. 2-5A activates the endoribonuclease 2-5A-dependent RNase L, causing degradation of single-stranded RNA with moderate specificity. The human 2-5A-dependent RNase is an 83.5 kDa polypeptide that has little, if any, RNase activity, unless 2-5A is present. 2-5A binding to RNase L switches the enzyme from its off-state to its on-state. At least three 2',5'-linked oligoadenylates and a single 5'-phosphoryl group are required for maximal activation of the RNase. Even though the constitutive presence of 2-5A-dependent RNase is observed in nearly all mammalian cell types, cellular amounts of 2-5A-dependent mRNA and activity can increase after IFN treatment. One well-established role of the 2-5A system is as a host defense against some types of viruses. Since virus infection of cells results in the production and secretion of IFNs, and since dsRNA is both a frequent product of virus infection and an activator of 2-5A synthesis, the replication of encephalomyocarditis virus, which produces dsRNA during its life cycle, is greatly suppressed in IFN-treated cells as a direct result of RNA decay by the activated 2-5A-dependent RNase. This review covers the organic chemistry, enzymology, and molecular biology of 2-5A and its associated enzymes. Additional possible biological roles of the 2-5A system, such as in cell growth and differentiation, human immunodeficiency virus replication, heat shock, atherosclerotic plaque, pathogenesis of Type I diabetes, and apoptosis, are presented.

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Section: Cleawage Specificitymentioning

confidence: 99%

The 2–5 A system: Modulation of viral and cellular processes through acceleration of RNA degradation

Player

Torrence

1998

Pharmacology & Therapeutics

245

195

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“…The protocol for binding of RNase L to a labeled derivative of (2'-5')A3, [32P](2'-5')A3pCp (S.A. 3,000 Ci/mmol) in a complex that is retained on nitrocellulose filters has been described [20]. Extracts were always thawed on ice to avoid inactivation of RNase L [22]. Photo-crosslinking of RNase L to (2'-5')A3pCp and analyses of the labeled proteins were performed essentially as described [20,23].…”

Section: Assays For Rnase Lmentioning

confidence: 99%

(2′‐5′)A_n‐dependent endoribonuclease: Enzyme levels are regulated by IFNβ, IFNγ, and cell culture conditions

Floyd-Smith

1988

J of Cellular Biochemistry

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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.

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Some properties of 2-5A binding/nucleolytic activities in gel filtered rabbit reticulocyte lysates

Wertheimer

Eslami

et al. 1985

Bioscience Reports

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Rabbit reticulocyte lysates, gel filtered on Sephadex G-25 with or without ATP (or its analogs), were preincubated at 37 degrees C and their subsequent binding to p3A4,3'-[32P]pCp was studied. Lysates filtered without ATP or in the presence of 0.1 mM 8-bromo-ATP, 1,N6-etheno-ATP, or ITP showed a time-dependent decrease in binding activity. This decrease was completely prevented when lysates were filtered with 0.1 mM ATP, 2'-deoxy-ATP, beta-gamma-methylene-ATP, or ATP-gamma-S. The stability of binding provided by ATP or 2'-deoxy-ATP analogs corresponds to a more active 2-5A dependent endonucleolytic (RNAase L) activity based on studies using [3H] viral mRNA. Chromatography on heparin-agarose showed that ATP-supplemented gel-filtered reticulocyte lysates had a different p3A4,3'-[32P]pCp binding activity elution-profile than lysates gel-filtered in the absence of ATP. Covalent cross-linking of periodate-oxidized p3A4,3'-[32P]pC to gel-filtered lysates, preincubated at 0 degree C or 37 degrees C for 30 min, showed the following results: all lysates gave a major cross-linking of the radioactive ligand to an 80 000 dalton polypeptide, regardless of the temperature of preincubation, lysates gel-filtered without ATP, with 0.1 mM ITP, or beta-gamma-methylene-ATP, showed a significant reduction in the cross-linking of the 80 000 dalton protein, after preincubation at 37 degrees C for 30 min. This decrease was accompanied by an increase in the labeling of two smaller polypeptides.

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Effect of temperature on ppp(A2′ p)nA binding protein activities in rabbit reticulocyte lysates and other mammalian extracts

Cited by 9 publications

References 23 publications

The 2–5 A system: Modulation of viral and cellular processes through acceleration of RNA degradation

The 2–5 A system: Modulation of viral and cellular processes through acceleration of RNA degradation

(2′‐5′)A_n‐dependent endoribonuclease: Enzyme levels are regulated by IFNβ, IFNγ, and cell culture conditions

Some properties of 2-5A binding/nucleolytic activities in gel filtered rabbit reticulocyte lysates

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Effect of temperature on ppp(A2′ p)nA binding protein activities in rabbit reticulocyte lysates and other mammalian extracts

Cited by 9 publications

References 23 publications

The 2–5 A system: Modulation of viral and cellular processes through acceleration of RNA degradation

The 2–5 A system: Modulation of viral and cellular processes through acceleration of RNA degradation

(2′‐5′)An‐dependent endoribonuclease: Enzyme levels are regulated by IFNβ, IFNγ, and cell culture conditions

Some properties of 2-5A binding/nucleolytic activities in gel filtered rabbit reticulocyte lysates

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(2′‐5′)A_n‐dependent endoribonuclease: Enzyme levels are regulated by IFNβ, IFNγ, and cell culture conditions