Figure 17.

Protodermal gene expression during embryogenesis.

(A) At the octant stage AtML 1, PDF1 and PDF2 are expressed in all the apical cells of the embryo proper.

(B) At the dermatogen stage, expression of these genes is restricted to the outer cells and the expression of other genes such as WUSCHEL and the class III HD-ZIP genes are specifically upregulated within the inner cells.

(C–F) Images of fluorescent reporter constructs for the expression of AtML1. C: AtML1 reporter expression in both the apical and basal cell after division of the zygote. Images C–F reproduced/adapted from Takada and Jürgens (2007) with permission from The Company of Biologists.

(D) At the dermatogen stage the reporter has been downregulated in the inner cells.

(E, F) In the late globular and heart stages respectively, the AtML1 reporter marks the outer protodermal layer.