DELAYED PRONUCLEUS FORMATION IN MOUSE EGGS DERIVED FROM c-MOS-HETEROZYGOUS OOCYTES

摘要

The c-mos proto-oncogene product is essential for the meiotic arrest at the second metaphase in mouse oocytes (Hashimoto et al., 1994). c-mos-deficient oocytes are parthenogenen'cally activated and lose the ability to be fertilized. In contrast, c-mos-heterozygous mutant oocytes could be fertilized and then develop and grow into adult mice. Detailed cytological analysis revealed that the pronucleus formation in fertilized eggs derived from the c-mos-heterozygous mutant oocytes were significantly delayed comparing with wild-type eggs. Then the delay of early development was overcome prior to the first cleavage. Present results suggest that the timing of pronucleus formation in mouse eggs is controlled under the influences of c-mos expression levels.