Figure 2. Co-localization of CSI1, CESA complexes, and microtubules. (A) Wild-type seedlings co-expressing GFP-CESA6 and RFP-CSI1: the co-alignment of CSI1 and CESA complexes is evident in the merged time-averaged image. (B) Wild-type seedlings co-expressing YFP-TUA5 and RFP-CSI1: the co-alignment of CSI1 and microtubules is evident in the merged time-averaged image. (C) Wild-type seedlings co-expressing RFP-TUA5 and YFP-CESA6: the co-alignment of CESA complexes and microtubules is evident in the merged time-averaged image. (D) In csi1 seedlings co-expressing YFP-CESA6 and RFP-TUA5, CESA particles are randomly distributed, their time-averaged trajectories are apparently shorter and rarely co-localized with microtubules. Note that the large, roughly circular structures in the GFP-CESA6 (A) and YFP-CESA6 (C) images are Golgi bodies. The time-averaged images are projections of 60 frames (~5 min) acquired at 5 sec intervals. Bars = 10 µm. Methods described further in reference 15.