UASt regulatory sequences drive expression of the complete open reading frame of the Hsap\NUMB 'PTB[L]PRR[S]' alternative isoform (isoform 2), which contains the long version of the PTB domain (contains an 11 amino acid residue insertion relative to the short form) and the short version of the PRR domain.
Overexpression of Hsap\NUMBScer\UAS.PTBL-PRRS (or Hsap\NUMBScer\UAS.PTBS-PRRS) leads to dramatic wing margin balding (much more severe than Hsap\NUMBScer\UAS.PTBS-PRRL), when driven by Scer\GAL4bbg-C96, compared to controls; this represents a transformation toward neuronal fate.