Transposition of the LINE-like retrotransposon TART to Drosophila chromosome termini.

TART, a telomere-associated DNA element from Drosophila, is shown in this paper to have structural homology to LINE (long interspersed element)-like retrotransposons and to transpose to broken chromosome ends. TART DNA was detected by in situ hybridization in 7 of 10 independent additions of DNA to a chromosome end. We found evidence that a TART element had transposed to the chromosome end in each of two additions that were examined in detail. From the DNA sequence of a TART element that recently transposed, we infer that TART encodes two proteins having significant sequence similarity to the putative proteins of many LINEs. These results support the hypothesis that TART elements preferentially retrotranspose to the termini of chromosomes as part of the essential process by which Drosophila telomeres are maintained.