Akt expression in mouse oocytes matured in vivo and in vitro

Cecconi, Sandra; Rossi, Gianna; Santilli, Adriana; Stefano, Leonardo Di; Hoshino, Yumi; Sato, Eimei; Palmerini, Maria Grazia; Macchiarelli, Guido

doi:10.1016/j.rbmo.2009.10.011

« Previous Next »Reproductive BioMedicine Online
Volume 20, Issue 1 , Pages 35-41, January 2010

Akt expression in mouse oocytes matured in vivo and in vitro

Sandra Cecconi
- Department of Health Sciences, University of L’Aquila, Via Vetoio, 67100 L’Aquila, Italy
- Corresponding author.
Gianna Rossi
- Department of Health Sciences, University of L’Aquila, Via Vetoio, 67100 L’Aquila, Italy
Adriana Santilli
- Department of Health Sciences, University of L’Aquila, Via Vetoio, 67100 L’Aquila, Italy
Leonardo Di Stefano
- Department of Surgery, University of L’Aquila, Via Vetoio, 67100 L’Aquila, Italy
Yumi Hoshino
- Laboratory of Animal Reproduction, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
Eimei Sato
- Laboratory of Animal Reproduction, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
Maria Grazia Palmerini
- Department of Health Sciences, University of L’Aquila, Via Vetoio, 67100 L’Aquila, Italy
Guido Macchiarelli
- Department of Health Sciences, University of L’Aquila, Via Vetoio, 67100 L’Aquila, Italy

Received 24 April 2009; received in revised form 21 May 2009; accepted 7 October 2009. published online 07 December 2009.

Declaration: The authors report no financial or commercial conflicts of interest.

Abstract

To improve developmental competence of in vitro matured oocytes, culture medium can be supplemented with hypoxanthine (Hx) and FSH or epidermal growth factor (EGF) to trigger the activation of essential signalling pathways regulating meiotic resumption and progression. Since the serine/threonine kinase, Akt, contributes to the regulation of the meiotic cell cycle, this study analysed its expression level and localization at the meiotic spindle in oocytes matured in vivo or in vitro in the presence of Hx-FSH or Hx-EGF. Independently of culture conditions adopted, Akt mRNA concentration did not vary from germinal vesicle to metaphase I (MI), while at MII a significant decrease in Akt1 mRNA concentration was recorded in oocytes matured in vivo and in those stimulated by Hx-EGF (P < 0.05). Phoshorylated Akt protein content was similar in the different groups of MI oocytes, but it decreased at MII in oocytes matured either in vivo or in vitro with Hx-EGF. Ser-473-phosphorylated Akt was localized uniformly to the meiotic spindle in more than 90% of oocytes. These results indicate that, in mouse oocytes, Akt expression is differentially regulated during in vivo and in vitro maturation and suggest that EGF could be a positive modulator, even stronger than FSH, of oocyte meiotic maturation.

Keywords: Akt, EGF, FSH, IVM, mouse, oocyte

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Sandra Cecconi received her degree in Biological Sciences from the University of L’Aquila in 1981. She worked as Assistant Professor of Cell Biology in the Department of Biological Sciences and Technologies, University of L’Aquila from 1983 to 1999. Since 2000, Dr. Cecconi has been Associate Professor of Cell Biology in the Department of Health Sciences, University of L’Aquila. Her major scientific interests focus on the biology of reproduction, with particular regard to oocyte development in vitro and cryopreservation of oocytes and follicles.