Characterization and purification of DNA-RNA complexes related with 1731 and copia-like transposable elements in a Drosophila cell line.

DNA-RNA complexes were characterized and purified in a Drosophila melanogaster cell line. Such duplexes were shown to be specific of 1731 and other "copia-like" transposable elements. DNA-RNA complexes were purified through a Sephadex G-75 column from a global nucleic acid preparation or from a total RNA fraction prior to DNA-A and RNA-A treatment. They incorporated both labelled thymidine and uridine and their resistance or sensibility to enzymes or chemicals was consistent with that being expected with such hybrid molecules. From that intermediate form of reverse transcription, the resulting labelled cDNAs were obtained and were shown to be homologous to different drosophila "copia-like" transposable elements. These results suggest that most of the "copia-like" transposable elements were amplified through a reverse transcription pathway in Drosophila melanogaster.