The yeast transposon Ty1 generates duplications of target DNA on insertion

• Published in: Nature (London) 1980-07, Vol.286 (5771), p.414-418
• Main Authors: Gafner, Jürg, Philippsen, Peter
• Format: Article
• Language: English
• Subjects: Base Sequence; DNA Transposable Elements; DNA, Fungal - genetics; Humanities and Social Sciences; letter; multidisciplinary; Recombination, Genetic; Saccharomyces cerevisiae - genetics; Science; Science (multidisciplinary)
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/286414a0

Genetic elements which can transpose into different chromosomal sites causing modulation of gene expression have been found in maize 1 and several other organisms 2 . Most intensively characterized are those in enterobacteria: the insertion sequences, short DNA segments with probably no coding information, the transposable drug-resistance genes and the phage Mu (refs 2–4). The molecular details of transpositions in bacteria are under investigation; important results are the duplication of short target sequences at the integration site. 5–15 . and the identification of a transposase protein 16,17 . The yeast transposable element Ty 1 is present in about 35 copies per genome; it is 5,600 nucleotide pairs long with terminal direct repeats of 300 nucleotide pairs and is able to integrate into new chromosomal sites 18 . The resemblance of this yeast element to mobile elements in Drosophila melanogaster 19,20 is striking. The best characterized element, called copia, is present in about 30 copies in the Drosophila genome 19,21 and can integrate into many sites 22 , in some cases as part of a large transposable segment 23 . Another remarkable structural resemblance exists with the proviral DNA of retrovirus, which can insert into different chromosomal sites, as found in avian sarcoma virus transformed rat cells 24 . We focus here on the DNA sequence at the termini of element Ty 1 (ref. 18). Our sequence data show that transposition in yeast and bacteria have several features in common, such as integration into different sites without any apparent sequence specificity and duplication of five nucleotide pairs of target DNA at the integration site. In addition, we find that the terminal repeats in two Ty 1 elements consist of identical 338 nucleotide pairs.