COMPARATIVE-ANALYSIS OF STRUCTURE AND RETROTRANSPOSITION ACTIVITY IN 2 VARIANTS OF DROSOPHILA MOBILE ELEMENT MDG4 (GYPSY)

Two variants of mdg4 were isolated from Drosophila melanogaster strain s differing in the activity of its transposition, and comparatively an alyzed. Their long terminal repeats differed by point substitutions, i nsertions, and deletions. In total, about 5% of nucleotides were chang ed. In the coding region, about 0.6% of nucleotides were changed by po int substitutions, only 14 of which resulted in amino acid changes. Hy brid constructs containing fragments of both variants in various combi nations were used to transform a D. hydei cell line. Analysis of their ability to form new genomic copies showed that the efficiency of tran sposition is affected by two mutations located at the boundary of the putative protease and revertase domains and resulting in amino acid su bstitutions Thr --> Asp and Lys --> Arg.