Research article

Maternal Oct-4 is a potential key regulator of the developmental competence of mouse oocytes

Maurizio Zuccotti¹ , Valeria Merico² , Lucia Sacchi³ , Michele Bellone² , Thore C Brink⁴ , Riccardo Bellazzi³ , Mario Stefanelli³ , Carlo Alberto Redi⁵ , Silvia Garagna² and James Adjaye⁴

¹  Sezione di Istologia ed Embriologia, Dipartimento di Medicina Sperimentale, Universita' degli Studi di Parma, Parma, Italy

²  Laboratorio di Biologia dello Sviluppo, Dipartimento di Biologia Animale, Universita' degli Studi di Pavia, Pavia, Italy

³  Dipartimento di Informatica e Sistemistica, Universita' degli Studi di Pavia, Pavia, Italy

⁴  Molecular Embryology and Aging Group, Max-Planck Institute for Molecular Genetics, Berlin, Germany

⁵  Fondazione IRCCS, Policlinico San Matteo, Pavia, Italy

author email corresponding author email

BMC Developmental Biology 2008, 8:97doi:10.1186/1471-213X-8-97

Published:	6 October 2008

Abstract

Background

The maternal contribution of transcripts and proteins supplied to the zygote is crucial for the progression from a gametic to an embryonic control of preimplantation development. Here we compared the transcriptional profiles of two types of mouse MII oocytes, one which is developmentally competent (MII^SN oocyte), the other that ceases development at the 2-cell stage (MII^NSN oocyte), with the aim of identifying genes and gene expression networks whose misregulated expression would contribute to a reduced developmental competence.

Results

We report that: 1) the transcription factor Oct-4 is absent in MII^NSN oocytes, accounting for 2) the down-regulation of Stella, a maternal-effect factor required for the oocyte-to-embryo transition and of which Oct-4 is a positive regulator; 3) eighteen Oct-4-regulated genes are up-regulated in MII^NSN oocytes and are part of gene expression networks implicated in the activation of adverse biochemical pathways such as oxidative phosphorylation, mitochondrial dysfunction and apoptosis.

Conclusion

The down-regulation of Oct-4 plays a crucial function in a sequence of molecular processes that leads to the developmental arrest of MII^NSN oocytes. The use of a model study in which the MII oocyte ceases development consistently at the 2-cell stage has allowed to attribute a role to the maternal Oct-4 that has never been described before. Oct-4 emerges as a key regulator of the molecular events that govern the establishment of the developmental competence of mouse oocytes.