Shutdown is the only FKBP-family protein required for transposon silencing. (A) Above are shown the critical residues for the FKBP family peptidyl-prolyl cis-trans isomerase active site and the HSP90-interacting region in the TPR, as indicated, comparing the site in Drosophila Shutdown with those present in other family members. Residues in green indicate highly conserved residues with a known impact on PPIase activity, while those in yellow indicate a more poorly conserved region that has also been implicated. Below are evolutionary trees comparing each domain with family members present in other species. (B) The domain structures of the eight Drosophila FKBP family members are shown schematically. (C) Relative expression levels of Drosophila FKBP family members are shown for ovary and OSS RNAseq data sets. Relative enrichment in ovary versus other tissues is also shown. (D) Shown are relative HetA expression levels detected in ovaries from Drosophila engineered to express dsRNAs corresponding to each family member in the germline lineage. To the right is indicated whether dsRNA-expressing females are fertile (+) or sterile (−).
