Epo1p links the cER to the bud tip of the cell. (A) Cells containing (top) or lacking (bottom) EPO1 and expressing GFP-Sec62p as the ER marker were analyzed by fluorescence microscopy. Arrows indicate the cortex at the tip of the cells. (B) Regions of absent cER at the bud tip were counted in GFP-Sec62p–expressing WT and Δepo1 cells. Dashed lines separate the results of cells according to the lengths of their buds (22 < n < 144). (C) Effect of EPO1 deletion on cER inheritance. (left) WT and Δepo1 cells expressing GFP-Sec62p were scored for three stages of cER inheritance (no, tubular, or cER) and classified according to the length of their buds (71 < n < 104). (right) Images of Δepo1 cells (top and middle images) and WT cells (bottom image) expressing GFP-Sec62p and Spa2-Cherry exemplifying the three stages of cER inheritance. The same representative images are shown again in Fig. S3 D. (D) The FI profiles at the circumference of the bud were quantified for WT (left, n = 6) and Δepo1 cells (right, n = 15) coexpressing GFP-Sec62p and Spa2-Cherry. (top) Representative image of the inspected WT and inspected Δepo1 cells. (bottom) FIs plotted against the position at the surface of the bud of the two cells shown in the top images. Intensities are given as relative values to the FIs in the cytosol of the mother cell. Bars, 3 µm.