Figure 12.

Embryonic expression of WUS.

WUS transcripts are first detected in 16-cell dermatogen-stage embryos (red). Initially expressed in all subepidermal cells of the apical domain, WUS transcripts become gradually restricted to more central positions and deeper layers at the base of the shoot meristem. No functions have been assigned to WUS expression prior to the heart-stage and the molecular basis of WUS regulation is unclear. Precise regulation of WUS expression is critical to the formation of the apical pattern, since ectopic expression of WUS seems to confer stem cell identity at inappropriate sites (Gallois et al., 2004). Modified from Mayer and Jurgens (1998).