Cloning and molecular analysis of mdg4 retrotransposon from two Drosophila melanogaster lines differing in genetic instability
1991
Lyubomirskaya, N.V. | Arkhipova, I.R. | Il'in, Yu.V. | Kim, A.I.
We have investigated the structural organization of the Drosophila mobile element mdg4 (gypsy) in two lines, one of which (stable) possesses a small number of copies of this element whose location is constant. The second line (unstable) originating from the first shows an increase in both the number of copies of this element and the frequency of its transposition. We detected considerable structural differences in the mdg4 copies cloned from these two lines, involving point substitutions, deletions, and insertions at the level of the primary structure. Southern blot hybridization has shown that copies of one type only are present in a stable line and that mdg4 copies of another type are amplified in the unstable line. Furthermore we investigated the transcription activity of mdg4 in the given system and were able to show that despite density structural differences the DNA construction based on mdg4 copies of both the first and the second type show approximately the same transcription activity under transient expression conditions in the cell culture. While a high level of mdg4 transcriptions was observed, however, in the flies and embryos of the unstable line, it was not possible to detect the poly(A)+ RNA corresponding to mdg4 in the stable line.
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