Expression analyses in Drosophila ovaries

Suppressor of Hairy-wing [Su(Hw)] is a multi-zinc finger DNA binding factor required for gypsy insulator function and female germline development in Drosophila. The enhancer-blocking and barrier functions of the gypsy retrotransposon involve Su(Hw) binding to twelve clustered Su(Hw) binding sites (SBSs) and recruitment of the Centrosomal Protein of 190 kD (CP190) and Modifier of mdg4 67.2 kD isoform (Mod67.2) insulator proteins. In contrast, the Su(Hw) germline function involves binding to non-clustered genomic SBSs and does not require CP190 or Mod67.2. Here, we use genome-wide expression analyses in the ovary to identify the first Su(Hw) regulated target genes. Ovaries for RNA isolation were dissected from 4-6 hour old virgin females of wild type (Canton S and BL15598) and su(Hw) null sterile mutants (su(Hw)A2663/v and su(Hw)Pb/2) Drosophila melanogaster. At this stage of development, ovaries only contain egg chamber stages 1-8. Loss of Su(Hw) causes apoptosis at stage 9. Thus, the experimental design compares transcriptional changes in the ovary prior to induction nof apoptosis in su(Hw) mutants.