Figure 5.

YAP Promotes Pluripotency Induction Non-cell-Autonomously

(A) Experimental scheme illustrating the mixing of two populations of primary MEFs: one expressing GFP (EV or YAP) corresponding to the “feeder” cells and the other expressing OSKM-mCherry. The cells were FACS sorted and replated at varying ratios as indicated, at two plating densities (1 × 10⁴ or 2 × 10⁴ cells/cm²). Resulting iPSC colonies were scored on days 15–17 as shown in (B and C).

(B) Colony-forming efficiency (mCherry+) on day 15 of reprogramming.

(C) Nanog+ iPSC colonies on day 17, from cultures plated at 1 × 10⁴ cells/cm².

(D) Top: schema illustrating a co-culture device that allows physically separated cells to share medium. Each of two major wells has nine minor wells. After seeding cells in the individual minor wells, the major well was filled with medium so that it is shared among cells across the nine-minor-well unit. Bottom: schema illustrating the co-culture of mitotically inactivated feeders expressing either control (EV) or wtYAP fused to mCherry (YAP) in outer minor wells and reprogrammable GMPs in the central minor well.

(E) Representative images of Oct4:GFP+ iPSCs (bottom) formed in the center well, fed by either EV feeders or YAP feeders (top), on day 5 of reprogramming.

(F) Quantification of data shown in (E).

(G) Experimental scheme illustrating the preparation of conditioned medium.

(H) Quantification of Oct4:GFP+ iPSC colonies cultured with varying proportion of conditioned medium to fresh medium (in order from left to right: 10%, 25%, 50%, and 75%) on day 5 of reprogramming. Data from three biological replicates are displayed in (B, C, F, and H), repeated over at least three independent experiments.