Adenovirus late sequences linked to herpes simplex virus thymidine kinase may be introduced into eukaryotic cells and transcribed.

LTK-cells have been transformed to the TK+ phenotype by treatment with size-defined concatamers of HSV-1 TK DNA and Ad2 Bam H1 C fragment (42.0 - 59.5 map units). All TK+ transformants contained Ad2 DNA as well as HSV-1 TK sequences. In most cases several inserts of virus DNA were present, many in high copy numbers. Although no Ad2 transcription promoter was present in the transforming DNA, Ad2-specific sequences were detected in polyadenylated cytoplasmic RNA species from several cell lines.