Fig. 6. Angiopoietin signaling regulates Wnt7b expression and cell cycle stage-dependent cell death. (A,B) X-Gal staining of hyaloid vessels from Ang2^lacZ/+; Wnt7b^lacZ/+ (A) and Ang2^lacZ/lacZ; Wnt7b^lacZ/+ (B) animals. Macrophages are circled in red. (C) Wnt7b and Gapdh RT-PCR of laser captured macrophages from hyaloid vessels of P3 wild-type animals, injected intra-vitreally with Ang2 (Ang2) or sham injected (con). Data from three independent experiments are presented. (D) Ang1 and Gapdh RT-PCR from wild-type P5 hyaloid vessel mRNA. Whole eye RNA was used as a control. (E-H) Combined BrdU (green) and TUNEL (red) labeling of hyaloid vessels showing BrdU-positive VECs that are apoptotic (F, indicated by white arrowhead) and pairs of BrdU-positive daughter nuclei (G,H). (I,J) BrdU labeled cell fate mapping: red lines show the number of BrdU-TUNEL double labeled nuclei (I) and BrdU-positive daughter pairs (J) in left eye hyaloid vessels assessed over a 21 hour time-course after BrdU incorporation. The blue lines in I and J show similar quantification in the right, contralateral eye after Ang1 injection at t=6 hours. Significance levels: ^**P0.01, >0.001; ^***P0.001, >0.