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

Abstract

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-αs are expressed efficiently in NDV infected cells but only at low levels in poly rI·rC induced cells. MuIFN- β 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 α and β 1 mRNAs in the cells reached a maximum at 10 hr after the induction which indicates coordinate expression of α and β 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 β-actin gene was unaltered. These data indicate that enhancement of gene expression in virus infected cells in not limited to the interferon system.