Fig. 5. Rx3 accounts for the higher proliferation of eye field versus telencephalic precursors. (A,B) Immunodetection of the M-phase marker Phosphohistone-H3 (red nuclei) in the anterior neural plate of ckh^ne2611 mutants (right panel) and their wild-type siblings (left panel) at tail-bud stage (dorsal views, anterior left). tlc expression (ISH, blue) serves as a marker of the presumptive telencephalon in wild-type embryos and of the telencephalon+eye field in ckh^ne2611. (C,D) Schematic representation of the embryos in A,B to localize the presumptive telencephalic and eye fields in wild-type embryos (domains 3 and 1, respectively) and the corresponding territories in ckh^ne2611 siblings (domains 4 and 2, respectively) at tail-bud stage. (E) Number of PH3-positive cells in domains 1-4 (see C,D) in wild-type (red) versus ckh^ne2611 (gray) embryos. Bars indicate standard errors. Proliferation is significantly decreased in the presumptive eye field, but is unaltered in the presumptive telencephalon, in ckh^ne2611 compared with wild-type embryos at tail-bud stage (two-sample independent Student's t-test, P values are given in the text).