Gene transcription and regulation of oocyte maturation

The developmental potential of an embryo is dependent on the developmental potential of the oocyte from which it originates. The process of oocyte maturation is critical for the efficient application of biotechnologies such as in vitro embryo production and mammalian cloning. However, the overall efficiency of in vitro maturation remains low because oocytes matured in vitro have a lower developmental competence than oocytes matured in vivo. Furthermore, oocytes that have been exposed to gonadotropins have greater developmental competence than oocytes matured in the absence of gonadotropins. By understanding the molecular mechanisms underlying gonadotropin-induced maturation, improvement in oocyte maturation technologies may be expected as procedures to manipulate specific factors involved in signalling for resumption of meiosis are identified. The present review will focus on transcriptional mechanisms underlying the maturation of mammalian oocytes in vitro, as well as on the acquisition of oocyte developmental competence. In addition, a working model for the transcriptional control of mammalian oocyte maturation is proposed.