Studies of the UV-sensitivity of virus-specific RNA synthesis in cells infected or transformed by adenovirus 5 and SV 40.

The effect of UV-irradiation on host and virus-specific RNA synthesis in cells infected or transformed by tumor viruses (Ad 5 and SV 40) was studied. It was found that the synthesis of host and Ad 5 RNA in infected KB cells was almost euqally inhibited upon UV-irradiation; the transcription of the EcoRI produced fragements--fragment B was inhibited to a greater extent than fragment A, suggesting that the transcription of the whole Ad 5 genome starts from the left side. The transcription of viral sequences in transformed cells, on the other hand, was more resistant to UV-irradiation than the transcription of the host ones. The results obtained suggest that the small size of the virus transcriptions, or their location at the beginning of large host transcriptions, may be responsible for the observed data.