Fertilisability and developmental ability of mouse oocytes with reduced amounts of cytoplasm
T Wakayama, R Yanagimachi - Zygote, 1998 - cambridge.org
T Wakayama, R Yanagimachi
Zygote, 1998•cambridge.orgTo determine the minimal amount of cytoplasm necessary to support normal development of
mouse oocytes, mature unfertilised oocytes were reduced in size into approximately 1/2, 1/4
and 1/8 by removing the cytoplasm, then inseminated. More than 80% of 1/2-size oocyte
were fertilised normally and almost all fertilised eggs developed to blastocysts. When
transferred to foster females, 31% of the blastocysts developed into normal offspring. In
contrast, 1/4-and 1/8-size oocytes, although they were penetrable by spermatozoa and …
mouse oocytes, mature unfertilised oocytes were reduced in size into approximately 1/2, 1/4
and 1/8 by removing the cytoplasm, then inseminated. More than 80% of 1/2-size oocyte
were fertilised normally and almost all fertilised eggs developed to blastocysts. When
transferred to foster females, 31% of the blastocysts developed into normal offspring. In
contrast, 1/4-and 1/8-size oocytes, although they were penetrable by spermatozoa and …
To determine the minimal amount of cytoplasm necessary to support normal development of mouse oocytes, mature unfertilised oocytes were reduced in size into approximately 1/2, 1/4 and 1/8 by removing the cytoplasm, then inseminated. More than 80% of 1/2-size oocyte were fertilised normally and almost all fertilised eggs developed to blastocysts. When transferred to foster females, 31% of the blastocysts developed into normal offspring. In contrast, 1/4- and 1/8-size oocytes, although they were penetrable by spermatozoa and extruded the second polar bodies, could not reach the 2-cell stage. In these oocytes, sperm nuclei did not develop into full-sized pronuclei. These results suggest that an oocyte can develop to full term after losing about half its cytoplasm, but not more.
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