Figure 3.

Labeling of the endosomal structures accumulated in various mutants with positively charged Nanogold. Spheroplasts obtained from the MBY3 (vps4Δ) and CWY40 (vam3Δ) strains were incubated in the presence of 4 nmol of positively charged Nanogold at 4C for 15 min before being transferred to room temperature for 30 min. Spheroplasts were then fixed and processed as described in Materials and Methods. (A,B) The class E compartment typical of the vps4Δ cells. (A) A preparation in which the lumen of the vesicles and tubules composing this compartment has been lost, probably because it was not optimally fixable. (B) An example in which the lumen of these organelles remained preserved. (C,D) The MVB accumulated in the vam3Δ strain (arrows). M, mitochondria; MVB, multivesicular body; PM, plasma membrane; V, vacuole. Bar = 200 nm.