Alp7R and Alp7A interact; Alp7R is indispensable for the formation of dynamic Alp7A filaments. (A to D) Fluorescence microscopy images of strains expressing Alp7A-GFP by itself or in the presence of other components of the system (agarose pads containing 0.5% xylose; scale bar equals 1 μm, all panels are at the same scale). (A) JP3315 (PY79 with an integrated xylose-inducible copy of alp7A-gfp, carrying pPxylalp7R). Top, cell membranes (FM4-64) and GFP (Alp7A-GFP); middle, cell membranes (FM4-64) and DNA (DAPI); bottom, GFP (Alp7A-GFP) and DNA (DAPI). GFP panels were prepared from deconvolved images. (B) JP3311 (PY79 with an integrated xylose-inducible copy of alp7A-gfp and an integrated copy of alp7C, carrying pPxylalp7R). (C) JP3309 (PY79 with an integrated xylose-inducible copy of alp7A-gfp and an integrated copy of alp7C). (D) JP3161 (PY79 carrying an integrated xylose-inducible copy of alp7A-gfp). (B to D) Cell membranes and GFP. See also Fig. S5 to S7 in the supplemental material.