Differential regulation of interferon‐induced mRNAs and c‐myc mRNA by α‐ and γ‐interferons

Abstract

The extent and kinetics of induction have been determined for eight mRNAs induced by .alpha.- and .gamma.-interferons in HeLa cells. The mRNAs which code for a 2-5A synthetase, metallothionien II, HLA class I antigen and five unknown proteins were induced 2- > 100-fold by .alpha.-interferons. In the continued presence of .alpha.-interferon some mRNAs were maintained at the induced levels until at least 40 h, whereas others were induced only transiently. When the effects of .alpha.- and .gamma.-interferons were compared, the induced levels and kinetics were very similar for one mRNA (1-8) but were significantly different for the others. One mRNA (6-16) was induced more than 100-fold by .alpha.-interferon but not significantly by .gamma.-interferon. Parallel analysis of the level of c-myc mRNA showed it to decrease twofold in response to .alpha.-interferon, but to increase more than threefold in response to .gamma.-interferon, despite a more profound inhibition of cell growth by the latter. There must, therefore, be differences in how the levels of different mRNAs are sustained by .alpha.-interferons and how .alpha.- and .gamma.-interferons regulate the levels of the same mRNAs.