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The Cytoskeleton and Nuclear Disassembly during Germinal Vesicle Breakdown in Starfish Oocytes
Author(s) -
Stricker Stephen A.,
Schatten Gerald
Publication year - 1991
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.1991.00163.x
Subject(s) - nocodazole , colcemid , germinal vesicle , microbiology and biotechnology , microfilament , microtubule , biology , oocyte , cytoskeleton , colchicine , cytochalasin d , cytochalasin b , cytochalasin , biochemistry , genetics , cell , embryo
In response to maturation‐inducing hormone, prophase‐arrested oocytes of the starfish Pisaster ochraceus resume meiosis and undergo nuclear disassembly during a process referred to as germinal vesicle breakdown (GVBD). Time‐lapse video recordings of maturing oocytes reveal that the nucleus lengthens along the animal‐vegetal axis of the oocyte directly prior to GVBD. Neither taxol (10 μM) nor microtubule‐depolymerizing agents [colcemid (50 μM), colchicine (250 μM), or nocodazole (1 μM)] prevent the pre‐GVBD changes in nuclear shape from occurring, although correlative microscopical studies demonstrate that microtubules are nucleated (taxol) or depolymerized (colcemid, colchicine, nocodazole) at the concentrations listed above. The microtubule‐altering drugs also do not affect the time at which GVBD begins or ends. A 10 μM solution of the microfilament‐disrupting drug cytochalasin B (CB), on the other hand, essentially eliminates the pre‐GVBD elongation of the nucleus. CB also slightly delays the onset of GVBD and significantly lengthens the time required to complete GVBD. Such studies suggest that: (i) drug‐sensitive microtubules are not required for GVBD to proceed in a normal fasion; (ii) the pre‐GVBD changes in nuclear shape involve microfilament‐mediated events; and (iii) cytochalasin‐induced depolymerization of microfilaments retards the normal timing of GVBD.