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A copy of repetitive element 1360 is required for silencing of a pericentric transgene in Drosophila melanogaster
Author(s) -
Haynes Karmella A.,
Caudy Amy A.,
Elgin Sarah C.R.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a468-c
Subject(s) - euchromatin , heterochromatin , biology , position effect , genetics , drosophila melanogaster , gene silencing , constitutive heterochromatin , heterochromatin protein 1 , centromere , chromosome , gene
Drosophila melanogaster heterochromatin is located around centromeres, at telomeres and across chromosome four. The small fourth chromosome is mostly heterochromatic, yet its gene density is similar to the euchromatic domains. We used a mobile P element carrying the visible marker hsp70‐white to access heterochromatin for genetic and biochemical studies. Heterochromatic P inserts exhibit position effect variegation (PEV), the mosaic silencing of a euchromatic gene placed in or near heterochromatin. Our insert map suggests at least five heterochromatic and four euchromatic domains on the fourth, interspersed. We also found that deletions and duplications of genomic DNA flanking a P insert can alter reporter expression. A map of these end‐points suggests that silencing is dependent upon proximity to transposon 1360 ( hoppel ). We directly tested 1360 silencing function in vivo using P constructs carrying 1360 upstream of hsp70‐white . We find that 1360 is not sufficient to induce silencing within euchromatin. However, silencing is dependent upon 1360 at a pericentric locus. The presence of short RNA’s (~22n.t.) corresponding to 1360 points towards an RNAi‐driven mechanism for 1360 ‐mediated silencing.