title: Expression and cellular distribution of cyclin-dependent kinase 4 (Cdk4) and connexin 43 (Cx43) in porcine oocytes before and after in vitro maturation.
abstract: It is recognised that connexin 43 (Cx43) and cyclin-dependent kinase 4 (Cdk4) are involved in the cumulus cell-oocyte communication via gap junctions and the control of cell cycle progress. However, little is known about their mRNA expression pattern and encoded proteins distribution in porcine oocytes during in vitro maturation (IVM). Cumulus-oocyte complexes (COCs) were collected from 31 puberal crossbred Landrace gilts and analysed for their Cdk4 and Cx43 mRNA expression using RQ-PCR and for the respective protein expression by confocal microscopic observations. An increased Cdk4 and Cx43 mRNA expression was found in oocytes after IVM (P < 0.001 and P < 0.05, respectively). Confocal microscopic observations revealed a significant increase of Cdk4 protein expression in the cytoplasm of oocytes during the maturation process. The localisation of Cx43 changed from zona pellucida before to cytoplasm of oocytes after IVM. It is supposed that the increased expression of Cdk4 and Cx43 mRNA in oocytes after IVM is linked with the accumulation of a large amount of templates during the process of oocyte maturation. The translocation especially of Cx43 from the zona pellucida into the cytoplasm may be associated with a decrease in gap junction activity in fully grown porcine oocytes. Both Cdk4 and Cx43 can be used as 'checkpoints' of oocyte maturation.
authors: Poznań University of Medical Sciences Department of Histology and Embryology Poznań Poland Poznań University of Medical Sciences Department of Anatomy Poznań Poland.
authors: Bartosz
authors: B
authors: Kempisty
authors: Poznań University of Medical Sciences Department of Histology and Embryology Poznań Poland.
authors: Agnieszka
authors: A
authors: Ziółkowska
authors: Poznań University of Medical Sciences Department of Toxicology 30 Dojazd St. 60-631 Poznań Poland.
authors: Hanna
authors: H
authors: Piotrowska
authors: Poznań University of Life Sciences Department of Veterinary Poznań Poland.
authors: Paweł
authors: P
authors: Antosik
authors: Poznań University of Life Sciences Department of Veterinary Poznań Poland.
authors: Dorota
authors: D
authors: Bukowska
authors: Poznań University of Medical Sciences Department of Histology and Embryology Poznań Poland Poznań University of Medical Sciences Department of Anatomy Poznań Poland.
authors: Piotr
authors: P
authors: Zawierucha
authors: Poznań University of Life Sciences Department of Veterinary Poznań Poland.
authors: Jędrzej M
authors: JM
authors: Jaśkowski
authors: Leibniz Institute for Farm Animal Biology Department of Reproductive Biology Dummerstorf Germany.
authors: Klaus-Peter
authors: KP
authors: Brüssow
authors: Poznań University of Medical Sciences Department of Histology and Embryology Poznań Poland.
authors: Michał
authors: M
authors: Nowicki
authors: Poznań University of Medical Sciences Department of Histology and Embryology Poznań Poland.
authors: Maciej
authors: M
authors: Zabel
keywords: Cyclin-dependent kinase; connexin; expression; in vitro maturation; porcine oocyte