Potential of intense gamma-irradiation of host cells for analysis of virus-specified transcription and replication.

Intense gamma-irradiation from a cobalt source differentially affects macromolecular synthesis of cultured mammalian cells. Exposure of monkey BSC-1 or murine fibroblastic L2 cells to 40 or 70 krad (1 rad = 1 x 10(-2) J/kg) abolishes DNA and RNA synthesis almost entirely but reduces the formation of protein much less. A dose-response analysis of irradiation shows that synthesis of total RNA and the messenger component thereof, measured as the poly(A)-containing fraction, are equally diminished. Host cells in which formation of DNA and RNA are minimal can support normal or nearly normal replication and transcription rates of vesicular stomatitis and vaccinia viruses. Therefore, use of pretreatment with gamma-irradiation, as employed here, should prove to be generally useful in examining virus-related transcription under circumstances in which application of drugs affecting gene expression, such as actinomycin D, is deemed undesirable.