Premium
Effects of spindle removal on MPF and MAP kinase activities in porcine matured oocytes
Author(s) -
Goto Seitaro,
Naito Kunihiko,
Ohashi Satoshi,
Sugiura Koji,
Naruoka Haruna,
Iwamori Naoki,
Tojo Hideaki
Publication year - 2002
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.90022
Subject(s) - biology , microbiology and biotechnology , metaphase , kinase , maturation promoting factor , mitogen activated protein kinase , cyclin dependent kinase 1 , cell cycle , cell , biochemistry , chromosome , gene
Intracellular localization of maturation/M‐phase promoting factor (MPF) and mitogen activated protein (MAP) kinase in mature oocytes has been examined by immunocytochemical methods and the authors of these studies have reported that they are localized on spindles during M‐phase. Although these reports showed the relative localization of MPF and MAPK on spindles, it has never been shown whether these kinases are present in the cytoplasm and, if they are present, how many parts of the kinases are localized on the metaphase spindle. In the present study, we made quantitative analyses of MPF and MAP kinase localized on oocyte spindles by kinase assays and immunoblotting after removal of the spindles from porcine mature oocytes. First, we certified their intracellular distribution by immunocytochemical methods and observed sharp signals of cyclin B1 on spindle poles and MAP kinase signals on the microtubule of metaphase spindles. In contrast to these results by immunostaining, the amounts of MPF and MAP kinase localized on spindles examined by immunoblotting and kinase assays were undetectable and less than 20%, respectively. These results indicate that the immunocytochemical technique is a powerful method for showing relative localization, but it is not suitable for quantitative analysis, and that the removal of metaphase spindles from mature oocytes does not have a severe negative impact on the subsequent MPF and MAP kinase activity and on the cell cycle progression in early embryo development. Mol. Reprod. Dev. 63: 388–393, 2002. © 2002 Wiley‐Liss, Inc.