Fig. 3. GL3 and EGL3 expression and function in embryos. (A) Analysis of GL3 and EGL3 promoter activity in the root of mature wild-type (WT) embryos using GL3::GUS and EGL3::GUS reporter lines. GL3 and EGL3 are expressed in the same H-cell pattern in the embryonic root as in the post-embryonic root. (B) Expression of the GL2::GUS and CPC::GUS reporters in hypocotyl and root epidermis of mature wild-type and gl3 egl3 mutant embryos. GL2 and CPC promoter activity is reduced in the gl3 egl3 mutant in both hypocotyl and root (except that no CPC::GUS activity is detected in the embryonic root epidermis in either line).