Polarity screen to identify agonists of HSC expansion. (A) Schematic representation of the screening approach. (B) Summary of the HSC polarity genes in vitro to in vivo gain of function screen. Respective gene plasmids are labeled (∧ or *) in relation to respective vector backbones (see also supplemental Table 2). (C) Mean ± SEM of 3 validation experiments. (D) Protein expression of AP2A2 in transfected GP+E-86 cells. (E) Southern blot analysis on DNA extracted from BM (BM) and thymic tissues of 2 mice (mice 1 and 2), and hybridized with a green fluorescent protein–specific probe. (F) Flow cytometry from an Ap2a2-transduced recipient mouse sorted on donor CD45.1 cells.