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DISTRIBUTION OF MATURATION‐PROMOTING FACTOR IN STARFISH OOCYTE STRATIFIED BY CENTRIFUGATION
Author(s) -
KISHIMOTO TAKEO,
KUBOTA JUNKO,
KANATANI HARUO
Publication year - 1977
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1111/j.1440-169x.1977.00283.x
Subject(s) - cytoplasm , starfish , organelle , oocyte , golgi apparatus , microbiology and biotechnology , ultrastructure , vesicle , ficoll , centrifugation , biology , hyaline , germinal vesicle , biophysics , chemistry , anatomy , endoplasmic reticulum , biochemistry , botany , embryo , ecology , peripheral blood mononuclear cell , membrane , in vitro
In starfish, cytoplasm taken from maturing oocytes is capable of inducing breakdown of the germinal vesicle and subsequent maturation when injected into immature oocytes. The cytoplasmic factor has been designated as “maturation‐promoting factor” (MPF). Ooplasm was stratified by centrifugation of maturing oocytes in density‐graded Ficoll‐seawater, without disrupting the cell. Three strata were distinguished beginning with the centripetal side: oil cap, hyaline layer and yellow layer. MPF activity was shown to be localized in the hyaline layer. Electron microscopic observation revealed that the hyaline layer contains Golgi complexes, many lucent vesicles and multi‐vesicular bodies as distinct organelles, but seldom contains such inclusions as the lipid droplets forming the oil cap, mitochondria, yolk and pigment granules contained in the yellow layer. Based on these observations, a possible cytoplasmic component with MPF activity is discussed.