THE GAG POLYPEPTIDES OF THE DROSOPHILA-1731 RETROTRANSPOSON ARE ASSOCIATED TO VIRUS-LIKE PARTICLES AND TO NUCLEI

1731 is a Drosophila melanogaster retrotransposon whose nucleotide seq uence shows a proviral architecture with two long terminal repeats (LT Rs) framing two internal Open Reading Frames (ORFs), The pol ORF2 of t his mobile genetic element was demonstrated to code for an active Reve rse Transcriptase (RT) and the ORF1 is expected to code for the struct ural Gag proteins of the virus-like particles (VLP), Using specific an ti-Gag antibodies, me have characterized the 1731 Gag polypeptides exp ressed either in vitro or in Kc Drosophila melanogaster cultured cells , Together with the 1731 RT, the largest, likely post-translationaly-m odified Gag polypeptides are gathered into cytoplasmic virus-like part icles, Moreover and consistent with the nuclear localization signal pr esent in the Gag sequence, we observed that a short 1731 Gag polypepti de is associated to the cell nuclei.