Low molecular weight RNAs with homologies to cellular DNA at sites of adenovirus DNA insertion in hamster or mouse cells.

The adenovirus type 2 (Ad2)-transformed hamster cell line HE5 contains one or very few integrated copies of Ad2 DNA. At the site of insertion of Ad2 DNA, the cellular DNA sequence has been completely preserved and has homologies to small unpolyadenylated, cytoplasmic RNAs of 300 nucleotides in length and to minority populations of smaller RNAs present in HE5 cells and in normal hamster cells. The 300-nucleotide RNA is present on average in approximately 20 copies per cell. This RNA, and shorter RNAs, reveal homologies to the hamster DNA sequence of approximately 400 nucleotides to the right of the site of insertion of Ad2 DNA, which is present in one or very few copies per genome. The nucleotide sequence of the DNA segment homologous to this RNA does not contain open reading frames in excess of a sequence encoding 18 amino acids. Thus, it is unlikely that the small RNAs are actually translated and their function is unknown. The nucleotide sequence does not exhibit similarities to known low mol. wt. RNAs of eukaryotic origin. The low mol. wt. cellular RNA has been found in HE5 cells, in other hamster cell lines and organs, and also in mouse cells. There are differences with respect to size and abundance in the RNAs smaller than 300 nucleotides between HE5 cells and LSH hamster embryo cells. The adenovirus type 12 (Ad12)-induced mouse tumor CBA-12-1-T carries greater than 30 copies of integrated Ad12 DNA. The cellular DNA sequence at the site of Ad12 DNA insertion exhibits homologies to small RNAs (approximately 300 nucleotides long) from mouse cells.(ABSTRACT TRUNCATED AT 250 WORDS)