Interferon action: induction of specific proteins in mouse and human cells by homologous interferons.

Abstract

Treatment of mouse (Ehrlich ascites tumor and L929) and human (FS4, GM258, etc.) cells with homologous interferons results in the induction of several proteins. Extracts obtained from cells labeled with [35Simethionine in the absence or presence of interferon were fractionated on poly(I)poly(Cagarose columns. The proteins retained on the columns revealed, upon sodium dodecyl sulfate/polyacrylamide gel electrophoresis, three protein bands in mouse cells (Mr 120,000; 80,000; and 67,000) and two in human cells (Mr 120,000 and 80,000) which were detected in the extracts of interferon-treated but not of untreated cells. These proteins were retained on double-stranded RNA [poly(I)poly(C)agarosej columns but very poorly, if at all, on single-stranded RNA [poly(I) or poly(C)agaroseJ columns, suggesting that they have an affinity for double-stranded RNA. In addition, interferon treatment of human fibroblasts greatly increased the labeling of three other protein bands (Mr 88,000; 67,000; and 56,000) which were detected in whole extracts but were not appreciably retained on poly(I).poly(C)agarose columns. The appearance of the induced proteins was blocked by actinomycin D if added together with interferon, indicating that transcription of certain genetic information is required. The possible correlation between the induced proteins described here and the elevated levels of certain enzymes in interferontreated cells (a protein kinase and 2'-5'-oligoadenylate synthetase) is at present unclear.Interferons are known for their potent antiviral activity. The replication of a wide variety of RNA and DNA viruses is blocked in cells pretreated with interferon (1, 2). Interferon treatment also results in various other effects, such as: alterations at the cell surface, inhibition of cell multiplication, antitumor effects in experimental animals and in man, effects on immune functions, etc. (3, 4). The mechanism(s) whereby interferon treatment results in various biological effects remains to be elucidated.The establishment of the antiviral effect of interferon is blocked by actinomycin D (5-7) and by inhibitors of protein synthesis (6-8), suggesting that the expression of certain cellular genetic information is required. This is supported by experiments showing that enucleated cells fail to develop an antiviral effect upon interferon treatment (9, 10). Studies from various laboratories have revealed that the level of at least two enzymes is greatly elevated in various cell types upon interferon treatment. These are: (i) a protein kinase(s) which, in the presence of ATP and double-stranded (ds) RNA, phosphorylates at least two proteins of Mrs 64,000-67,000 and 35,000-38,000, and histones (11-14). The Mr 35,000-38,000 protein appears to be the small subunit of the initiation factor eIF-2 required for protein synthesis (15, 16). (ii) The other is an enzyme (2'-5'-oligoadenylate synthetase) which synthesizes 2'-5'-linked oligoadenylates with the structure pppA(2'p5'A)n from ATP in the presence of ds RNA (17, 18). These oligonucle...

Isolation of Daudi Cells with Reduced Sensitivity to Interferon. III. Interferon-induced Proteins in Relation to the Phenotype of Interferon Resistance

“…Furthermore, treatment of cells with actinomycin D blocked the induction of these proteins, indicating a requirement for the synthesis of new mRNA. There is now considerable evidence to suggest that a number of interferon-induced polypeptides are the products of de novo transcription and translation (Gupta et al, 1979;Knight & Korant, 1979;Rubin & Gupta, 1980). Indeed, Colonno (1983) has recently demonstrated the appearance of new mRNAs in human fibroblasts as early as 2 h after interferon treatment.…”

“…The expression of certain cellular gene(s) appears to be required for the development of interferon action (Taylor, 1964: Lockart, 1964 and the levels of a number of enzymes are markedly enhanced in interferon-treated cells (Kerr & Brown, 1978 ;Roberts et al, 1976: St Laurent et al, 1983. In addition, interferon appears to induce several proteins of unknown function (Ball, 1979: Colonno, 1983: Cooper et al, 1982: Farell et al, 1979: Gupta et al, 1979Horisberger et al, 1983: Knight & Korant, 1979: Leanderson et al, 1982: Rubin & Gupta, 1980Sundstr6m et al, 1983;Well et al, 1983). Cellular mutants resistant to interferon provide a valuable means~of studying the role of induced proteins in interferon action.…”

Increased rate of degradation of c-myc mRNA in interferon-treated Daudi cells.

“…For each time point, 10,tg of poly(A)+ RNA was prepared and analyzed as in Fig. 1 (26,27), histocompatibility antigens (23)(24)(25), and a number of proteins of unknown functions (28)(29)(30)(31)(32)(33). Although this was not the main purpose of these studies, it is worth noting that IFN increases rapidly but transiently the transcriptional activity of HLA-A2, whereas its mRNA accumulates over longer periods of time, in agreement with published data (23)(24)(25) Similar data reporting the absence of any significant modulation of the transcription rate of c-myc gene by IFN have been obtained recently (39).…”

Interferon Induction by Viruses. XVI. 2-Aminopurine Blocks Selectively and Reversibly an Early Stage in Interferon Induction

“…The concept was elaborated on recently with a model in which candidate molecules for a postulated interferon inducer receptor exist in the form of cellular proteins with high affinity binding for dsRNA (Marcus, 1984). The best defined of this class of molecules, some of which are inducible by IFN, are the dsRNA-dependent 2'-5' oligo(A) synthetase and protein kinase (Gupta et al, 1979;Penn & Williams, 1985;Lengyel, 1982).…”