Evidence for a transcription-control region of Simian virus 40 in the adenovirus 2--Simian virus 40 hybrid, Ad2+ND 1 .

The complementary DNA strands of the nondefective adenovirus 2 (Ad2)-simian virus 40 (SV40) hybrid virus, Ad2(+)ND(1), were separated by isopycnic banding in a CsCl density gradient in the presence of synthetic polyribonucleotides. Separated strands were used in DNA-RNA hybridization reactions with RNA from cells productively infected by Ad2 or SV40, and with complementary SV40 RNA transcribed asymmetrically in vitro. About five times as much Ad2 RNA hybridized to the light stand of Ad2(+)ND(1) as to the heavy strand. Complementary RNA and early SV40 RNA (RNA synthesized before viral DNA replication) had significant homology only with the light strand. Only half as much of a preparation of RNA synthesized before and after viral DNA replication (early-plus-late SV40 RNA) hybridized to the light strand as to the heavy strand. These results indicate that templates for both late and early SV40 RNA are present in Ad2(+)ND(1). Therefore, the small SV40 segment within this virus (10-18% of the SV40 genome) must contain a transcription-control region. Ad2(+)ND(1) should thus be useful in the selective study of transcription as it occurs in cells infected by the oncogenic virus SV40.