Three-dimensional analysis of protein aggregate body in Saccharomyces cerevisiae cells.
Modified genes of peroxisomal isocitrate lyase of Candida tropicalis (CT-ICL) were constructed and expressed in Saccharomyces cerevisiae cells. We observed subcellular localization of expressed products of the mutant CT-ICL genes by immunoelectron microscopy. An unknown structure termed a protein aggregate body (PAB) storing the expressed product was observed in cytoplasm in various mutants (Kamasawa et al. (1996) J. Electron Microsc. 45: 491-497). We chose two typical cells harbouring the mutant ICL genes delta 550 and delta 237-339 to analyse the ultrastructure and three-dimensional (3D) structure of PABs. The PABs had a homogeneous matrix with a wavy periphery in the cell image using a high-pressure freezing fixation method. Although PABs could not be separated from the cytoplasm or mitochondria under a confocal fluorescence microscope, 3D reconstruction of serial electron micrographs clearly showed the PAB was an independent structure of varying size and had the shape of an incomplete sphere. A cell was sometimes observed to have multiple PABs.
Kamasawa
N
N
Department of Chemical and Biological Sciences, Faculty of Science, Japan women's University, Tokyo, Japan.
Yoshida
T
T
Ueda
M
M
Tanaka
A
A
Osumi
M
M
D002175:Candida / Q000201:enzymology / Q000235:genetics; D005615:Freezing; D007091:Image Processing, Computer-Assisted; D002479:Inclusion Bodies / Q000201:enzymology / Q000648:ultrastructure*; D007522:Isocitrate Lyase / Q000032:analysis* / Q000235:genetics; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000648:ultrastructure
D007522:Isocitrate Lyase