Fig. 8. Cell proliferation and programmed cell death in the PSM of rs/rs. BrdU incorporation (A,B) and TUNEL (C,D) assays were performed on serial frozen sections of E10.5 control (A,C) and rs/rs (B,D) embryos. Note that a number of BrdU-positive cells are present in the PSM (psm) as well as in somites (so) of both rs/rs (B) and control (A). The numbers of apoptotic cells detected by TUNEL in the PSM (examples indicated by the black arrowheads in C,D) are comparable between control and rs/rs. Tb, tail bud. Scale bars: 100 µm.