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Cytoskeletal organization of rat oocytes during metaphase II arrest and following abortive activation: A study by confocal laser scanning microscopy
Author(s) -
ZernickaGoetz Magdalena,
Kubiak Jacek Z.,
Antony Claude,
Maro Bernard
Publication year - 1993
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080350210
Subject(s) - microtubule , metaphase , microbiology and biotechnology , biology , microtubule organizing center , kinetochore , cytoplasm , advanced spaceborne thermal emission and reflection radiometer , spindle pole body , spindle apparatus , multipolar spindles , cytoskeleton , cell division , centrosome , genetics , chromosome , cell , cell cycle , remote sensing , geology , gene , digital elevation model
Abstract In metaphase II arrested rat oocytes (M il), microtubles were found in the taper‐shaped meiotic spindle and in the cytoplasm as asters and free microtubules. Whereas spindle microtubules were acetylated, those located in the cytoplasm were not. Cytoplasmic microtubules were also labile as assessed by mild cooling. In contast to mouse oocytes, rat microtubule organizing centers (MTOCs) did not react with MPM‐2 antibody by immunofluorescence despite the fact that this antibody reacts with several proteins as shown by immunoblot. However, cytoplasmic MTOCs in M II‐arrested rat oocytes could be detected by their nucleating capacity in the presence of taxol, a drug that induced the formation of numerous cytoplasmic asters. In addition, taxol caused a change in the spindle shape and the formation of astral microtubules at the spindle poles. Meiotic spindles (as well as chromosomes devoid of microtubules after nocodazoletreatment) were overlaid by an actin‐rich domain. Spontaneous abortive activation led to the extrusion of the second polar body followed by another metaphase arrest— metaphase III; however, normal spindles did not form and dispersed chromosomes surrounded by microtubles were observed. Electron microscopic studies confirmed these observations and revealed that the kinetochores are located deep within the chromosomes in contrast to mouse kinetochores, and this might be responsible for the absence of a metaphase III spindle in the rat oocyte. Induced activation caused transition to interphase with the formation of a characteristic microtubule network. This study shows that there are several significant differences in the cytoskeletal organization of rat and mouse oocytes. © 1993 Wiley‐Liss, Inc.