Figure 2.

MPC Expression in the Seed Is Endosperm Specific, and a Translational but Not Transcriptional Reporter Is Imprinted.

(A) to (C), (E), and (F) Nuclear-targeted translational MPC reporter containing the MPC promoter and gene body fused to GFP (proMPC-MPC-GFP).

(A) The reporter is active in the central cell of an unfertilized ovule (arrow and inset).

(B) Reporter expression increases after fertilization; this seed from a self-fertilized proMPC-MPC-GFP plant shows the four nuclei resulting from the first two endosperm divisions. The arrow points to one of the nuclei that lies in a different focal plane to the other three and is therefore fainter.

(C) proMPC-MPC-GFP × proMPC-MPC-GFP.

(D) Wild-type Col (Col × Col).

(E) and (F) The translational reporter is imprinted.

(E) proMPC-MPC-GFP (♀) × Col (♂).

(F) Col (♀) × proMPC-MPC-GFP (♂).

(G) and (H) Nuclear-targeted transcriptional reporter (proMPC-GFP). Confocal images with GFP in green and chlorophyll autofluorescence in red. Some images show green autofluorescence in the seed coat. The transcriptional reporter is expressed when contributed by either parent. All seeds in (C) to (H) are at 4 DAP.

(G) proMPC-GFP (♀) × Col (♂).

(H) Col (♀) × proMPC-GFP (♂).

Bars = 2 μm in (A) and (B) and 100 μm in (C) to (H).