UASp regulatory sequences drive expression of a fusion protein in which the N-terminal 46 amino acids of Incenp (the Borealin-Survivin domain) have been replaced with borr coding sequence that lacks the C-terminal domain (only borr amino acids 1-17 are present). In addition, sequence encoding the two putative Su(var)205 protein interaction sites has been deleted from the Incenp sequence. Eight silent mutations have also been introduced into the region corresponding to Incenp amino acids 437-441; this renders the construct resistant to RNAi mediated by P{TRiP.GL00279}.