Figure 5.

Overexpression of GAP Leads to Arrest of Germination and Growth.

(A) Overview picture of pollen tubes bombarded with LAT52-driven RhoGAP1 cDNA, together with YFP to visualize transfected pollen and pollen tubes, and YFP fusions of full-length RhoGAP1 proteins (top row). Bottom panels show images of pollen tubes transformed with YFP fusions of RhoGAP1 truncations: Nterm, N terminus of RhoGAP1 (amino acids 1 to 95); Ncrib, N terminus and CRIB domain (amino acids 1 to 143); crib, CRIB domain (amino acids 96 to 126); cribC, CRIB domain and C terminus (amino acids 96 to 391); Cterm, C terminus (amino acids 127 to 391). All truncated proteins were expressed with YFP attached to the N or C terminus, as indicated in the figure. Pictures were taken 20 h after bombardment. Arrows indicate nongerminating pollen expressing the respective YFP fusion protein. Background fluorescence is derived from nontransfected pollen grains. Bar = 100 μm.

(B) High magnification of a pollen tube overexpressing RhoGAP1 and YFP to visualize the tube, both under the LAT52 promoter. The top panel shows a projection of a confocal stack, and the bottom panel shows a differential interference contrast image of the same tube. Bar = 10 μm.