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Cytoplasmic factors that control nuclear behavior in mammalian oocytes: A re‐evaluation of studies performed as a student of Yoshio Masui
Author(s) -
Clarke Hugh J
Publication year - 1998
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1111/j.1768-322x.1998.tb01063.x
Subject(s) - germinal vesicle , biology , oocyte , metaphase , premature chromosome condensation , meiosis , microbiology and biotechnology , cytoplasm , chromatin , prophase , histone , somatic cell , sperm , chromosome segregation , dna replication , chromosome , genetics , dna , embryo , gene
Studies performed by the author in the laboratory of Dr Yoshio Masui are reviewed and interpreted in the light of subsequent findings. The first series of studies indicated that that chromosome condensation during meiotic maturation of mouse oocytes is controlled initially by a stable protein that decays during maturation and subsequently by an unstable protein synthesized after germinal vesicle breakdown. Cyclin B is present in immature oocytes, becomes partially degraded near metaphase I and then re‐accumulates, suggesting that this may be protein whose activity was inferred from the original results. The second series of experiments indicated that factors which appear in the oocyte cytoplasm during maturation are able to remodel the sperm into metaphase‐like chromosomes, and that the supply of these factors is limited. Recent work indicates that these factors are required for the assembly of histones onto the sperm DNA, and has identified two molecular species, mNAP‐1 and NPM‐3, known to promote replication‐independent chromatin assembly in somatic cells, that are expressed in oocytes.