Mammalian oocyte maturation

The oocyte is a very special cell within an organism. Its maturation repres ents the final step of a long process of preparation for successful fertili zation and embryo development. This preparation progresses throughout folli culogenesis. From birth to ovulation (which could take several years) the o ocyte's nucleus remains blocked at the germinal vesicle stage (meiotic prop hase) due to follicular inhibition of meiotic progression. Meiosis resumes only in a fully grown oocyte (in a fully grown follicle) following the preo vulatory LH surge. This review describes some of the regulatory mechanisms involved in the control of meiotic arrest/resumption in the oocyte. We atte mpt to find some indicators of oocyte competence and to examine how this kn owledge can be used in in vitro maturation techniques for assisted reproduc tion in humans and animals, basic studies of cell cycle control,and impleme ntation of new biotechnologies.