title: Structure and reversion of an adenovirus type 2 mutant containing a duplication of the left end of the genome at the right end.
abstract: A mutant (dp 201) of human adenovirus type 2 has been isolated that has the left 3% (1110 bp) of the genome duplicated at the right terminus. The structure of the mutant genome was studied by restriction endonuclease analysis and by direct DNA sequence analysis. The duplication has resulted in a deletion of 10 bp of the right inverted terminal repeat (ITR) at the junction of right and left end sequences. This internal ITR is not active in initiation or termination of DNA synthesis. Two subclones of dp 201 that bear a deletion between map positions 2.1 and 6.8 encompassing early gene blocks E1a and E1b were also isolated. One of these isolates (dl 201.1) retains the left end duplication and the other isolate (dl 201.2) lacks the left end duplication and is an apparent revertant of dl 201.1. The original mutant dp 201 also reverts to a wild type sequence at a low rate. Since 10 base pairs of the right ITR are deleted in the mutant, reversion must involve a repair mechanism using one of the two complete left end ITRs in the mutant genome. The mechanisms by which this reversion may occur are discussed.
mesh_terms: D000260:Adenoviruses, Human / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D004260:DNA Repair; D004261:DNA Replication; D004279:DNA, Viral / Q000378:metabolism; D005814:Genes, Viral; D009154:Mutation; D012091:Repetitive Sequences, Nucleic Acid; D014779:Virus Replication
chemical_list: D004279:DNA, Viral