Arabidopsis EBP1 is expressed and localized in actively dividing tissues during root development. Representative differential interference contrast images of EBP1 expression in the primary root (A) and during lateral root development (B) in the transgenic pEBP1:GUS lines after 3h GUS staining. The images of the different stages of lateral root development belong to the same root. C, Confocal microscopy images in the propidium-iodide–stained root sample of the pEBP1:CFP lines. D to F, Confocal microscopy images represent the localization of the EBP1-YFP protein in the pgEBP1:YFP transgenic line in the primary (D) and secondary (E) meristems. The enlarged sections of the meristematic region in (F) and of a lateral root initial in (E) are showing cytoplasmic localization of the fusion protein (scale bar = 25 μm), whereas (G) and (H) illustrate the lower level of expression in the slowly dividing stem cells and QC. In each case, 5- to 6-d-old seedling were analyzed. White arrow points toward the QC, and the white arrowhead in (E) labels the occasional nuclear localization of the EBP1-YFP protein in the differentiation zone. The merged image in (A) is a composite of two consecutive overlapping images of the same root, taken with the same median focal plane. The enlarged image in (F) comes from the meristematic region, labeled by two white lines in (D). Scale bars = 50 μm, unless stated otherwise.