Increased turnover of vaccinia virus-specific immediate early RNAs in interferon-treated chick embryo fibroblasts.

The synthesis and steady state level of immediate early vaccinia virus-specific RNAs in interferon-treated chick embryo fibroblasts were determined by blot hybridization analysis using the cloned restriction endonuclease fragment pEJ 18 containing the gene of vaccinia virus WR-specific DNA polymerase as a probe. Even though early vaccinia virus WR RNA was still synthesized, accumulation of immediate early viral RNAs was strongly inhibited. Accumulation of beta-actin RNA was not affected. This indicated an enhanced degradation of vaccinia virus WR-specific early RNAs in interferon-treated chick embryo fibroblasts. This notion was supported by Northern blot analysis which revealed degradation of residual RNA of vaccinia virus WR-specific DNA polymerase. In contrast to interferon-treated mouse L 929 cells, ribosomal RNA is not degraded in interferon-treated vaccinia WR-infected chick embryo fibroblasts.