Interferon modulation of c-myc expression in cloned Daudi cells: relationship to the phenotype of interferon resistance.

Abstract

Treatment of interferon-sensitive Daudi cell with electrophoretically pure human interferon alpha markedly reduced the level of c-myc mRNA, increased the level of class I histocompatibility antigen (HLA) mRNA, and did not affect the level of actin mRNA within the same cells. In contrast, the level of c-myc mRNA or HLA mRNA did not change significantly following interferon treatment in different clones of Daudi cells selected for resistance to the antiproliferative action of interferon. These cells possessed interferon receptors, however, and responded to interferon modulation of other genes, including 2',5' oligoisoadenylate synthetase (M. G. Tovey, M. Dron, K. E. Mogensen, B. Lebleu, N. Metchi, and J. Begon-Lours, Guymarho, J. Gen. Virol., 64:2649-2653, 1983; M. Dron, M. G. Tovey, and P. Eid, J. Gen. Virol., 66:787-795, 1985). A clone of interferon-resistant Daudi cells which had reverted to almost complete sensitivity to both the antiproliferative action of interferon and the interferon-enhanced expression of HLA mRNA remained refractory, however, to interferon modulation of c-myc expression, suggesting that a reduced level of c-myc mRNA may not be a prerequisite for inhibition of cell proliferation in interferon-treated cells. Our results do not exclude the possibility, however, that posttranscriptional modification(s) of c-myc expression may precede an inhibition of cell proliferation in interferon-treated cells.

N-myc amplification causes down-modulation of MHC class I antigen expression in neuroblastoma

“…Indeed, others have shown that interferon strongly inhibits expression of the related c-myc gene (Jonak and Knight, 1984;Dron et al, 1986). However, in the present case N-myc expression is unaffected following interferon treatment (Figure 56).…”

Interferon regulatory factor-1 (IRF-1) is a mediator for interferon-γ induced attenuation of telomerase activity and human telomerase reverse transcriptase (hTERT) expression

“…IFNs suppress c-Myc expression post-transcriptionally in some cell systems (Jonak and Knight, 1984;Dron et al, 1986). To determine whether c-Myc is involved in IFN-g-induced downregulation of telomerase activity in human cervical Relation between telomerase activity and G1 arrest IFN-g causes cell growth arrest at the G1 phase of the cell cycle (Bromberg et al, 1996;Horvath et al, 1996).…”

Priming affects the activity of a specific region of the promoter of the human beta interferon gene.

“…Clone DIF3 REV5, which had reverted to almost full sensitivity to both the antiviral and . Polyadenylated RNA (5 ,ug) was then electrophoresed in a denaturing agarose gel and transferred to a nitrocellulose filter as described previously (4). The blot was hybridized with the same human IFN-P probe as described above and exposed for 24 h at -800C.…”