Differential effect of poly rI.rC and Newcastle disease virus on the expression of interferon and cellular genes in mouse cells.

The expression of type I murine interferon (MuIFN) genes and several other cellular genes was examined in poly rI.rC induced and Newcastle disease virus (NDV) infected mouse cells. Northern analysis of RNA from induced L cells revealed that the MuIFN-alpha s are expressed efficiently in NDV infected cells but only at low levels in poly rI.rC induced cells. MuIFN-beta 1, however, is expressed equally well in cells treated with poly rI.rC or infected with NDV. As shown by the use of a probe specific for poly rI.rC, interferon induction correlates with the cellular uptake of poly rI.rC into the cells. The relative levels of alpha and beta 1 mRNAs in the cells reached a maximum at 10 hr after the induction which indicates coordinate expression of alpha and beta 1 interferon genes. The effect of viral infection on the expression of two murine genes coinduced with interferon (pMIF20/11 and pMIF3/10) and several cellular genes was also examined. While pMIF20/11 is an inducible gene, the pMIF3/10 gene is expressed constitutively in mouse L cells. Viral infection, but not poly rI.rC treatment, enhanced the expression of the pMIF3/10 gene, as well as two other cellular genes; H-2 and c-myc, however, the expression of beta-actin gene was unaltered. These data indicate that enhancement of gene expression in virus infected cells in not limited to the interferon system.