Drosophila telomere transposons: genetically active elements in heterochromatin.

摘要: In Drosophilatwo non-LTR retrotransposons, HeT-Aand TART, offer a novel experimental system for the study of heterochromatin. These elements, found only in heterochromatin, form Drosophilatelomeres by repeated transposition onto chromosome ends. Their yields arrays repeats larger and more irregular than produced telomeras; nevertheless, transpositions are, principle, equivalent to telomere-building action telomerase. The identification HeT-Apromoter has given first view molecular structure promoter active telomere-specific elements are unusual having large amount non-coding sequence. Like many other heterochromatic sequences, HeT-Anon-coding sequence repetitive organization strongly conserved within species, although itself can undergo significant change between species (atypical example concerted evolution). Such sequences could be important cell, perhaps as docking stations essential proteins.