Effect of genetic background and activating stimulus on the timing of meiotic cell cycle progression in parthenogenetically activated mouse oocytes.

P-22: Time Dependent Effect of Post Warming Interval on Microtubule Organization, Meiotic Status, and Parthenogenetic Activation of Vitrified In vitro Matured Sheep Oocytes

Background: It is a common practice to rest vitrified-warmed matured oocytes for 1-3 hours, as a treatment to recover spindle and cytoskeleton, before commencing a further treatment. Vitrified-warmed matured oocytes, however, are very sensitive and may resume meiosis spontaneously during this recommended rest time. Therefore, the aim of this study was to assess spindle and chromosome status as ...

I-18: The Role of Sex Chromosomes in Female Germ Cell Differentiation

Background When gonadal sex reversal occurs in mammalian species, the resultant XX males and XY females become infertile or subfertile, suggesting critical roles of sex chromosomes in germ cell differentiation. The objective of our study is to clarify the mechanism of infertility in the B6.YTIR (XY) sex-reversed female mouse, which can be attributed to a failure in the second meiotic division i...

O-11: Prenatal Oogenesis: Selecting the Qualityand Quantity of Oocytes in the OvarianReserve

Background: The purpose of this research programme is to improve understanding of the molecular and cellular processes that lead to selection of oocytes before birth. Vastly more oocytes are produced prenatally than can be utilised in reproductive life. Around 70%, of oocytes formed are eliminated before birth and never contribute to the ovarian reserve. After birth, the number of oocytes conti...

Mouse Oocytes and Embryos Cryotop-vitrification Using Low Concentrated Solutions: Effects on Meiotic Spindle, Genetic Material Array and Developmental Ability

A MAPK cascade couples maternal mRNA translation and degradation to meiotic cell cycle progression in mouse oocytes.

Mammalian oocyte maturation depends on the translational activation of stored maternal mRNAs upon meiotic resumption. Cytoplasmic polyadenylation element binding protein 1 (CPEB1) is a key oocyte factor that regulates maternal mRNA translation. However, the signal that triggers CPEB1 activation at the onset of mammalian oocyte maturation is not known. We provide evidence that a mitogen-activate...