Fig. 4. Immunolocalization of actin using subfamily-specific antibodies. (A) Western blot analysis of affinity-purified anti-act4-1 antibody (lanes 1-3) and anti-act5-1 antibody (lanes 4-6) against the recombinant act1-1 (L₂₆₁-G₃₆₆; lanes 1, 4), act4-1 (M₁-A₁₆₀; lanes 2, 5) and act5-1 peptides (H₁₇₅-L₂₉₀; lanes 3, 6), respectively. There is no crossreactivity between the isoforms. The double band in lane 2 is probably due to formation of dimers. (B-E) Localization of act4. (B,C) Median and superficial focus plane showing labeling of the oral cavity (oc), around a nascent food vacuole (fv), of cilia and at the cell cortex. (D,E) Median and superficial plane of a dividing cell. Note labeling of the cleavage furrow (cf) and of the old and new oral cavity (oc). (F) Superficial plane of a cell in an earlier stage of division. Again the cleavage furrow is labeled, as well as the old and the new oral cavities. (G) For comparison, a cell in the same dividing state as F, but labeled with an anti-act5 antibody, reveals no labeling of the cleavage furrow. Bars, 10 µm.