Expression of pregnancy-associated glycoprotein 1 and 2 genes in in vivo, in vitro and parthenogenetically derived preimplantation pig embryos
The objective of this study was to determine whether porcine PAG (poPAG) genes are expressed in embryos as they develop from the 1-cell stage to expanded blastocysts, and whether expression differed according to how embryos had been derived. Embryos at various preimplantation stages were assayed after in vivo fertilisation, after in vitro fertilisation of in vitro-matured oocytes, or following parthenogenetic activation of in vitro-matured oocytes. The presence of PAG transcripts was determined at the1-, 2-, and 4-cell, compact morula and blastocyst stages by reverse transcription-PCR procedures with PAG 1- and PAG 2-specific primers, followed by Southern blotting. The mRNAs for poPAG 1 and 2 were detected in in vitro-derived, in vivo-derived and parthenogenetically derived blastocyst stage embryos. In some replications poPAG 1 could be detected as early as the compact morula stage and poPAG 2 could be detected as early as the 4-cell stage. Our study revealed that poPAG 1 and 2 genes are expressed as early as the compact morula stage and 4-cell stage, respectively, in normal embryos and in parthenogenetically derived blastocysts. Thus it appears that the poPAGs are not maternally imprinted and they may be useful as potential candidates for markers of developmental competence.(Received November 6 00)
(Accepted January 11 01)
Key Words: Embryo; Pig; Porcine pregnancy-associated glycoprotein; RT-PCR.
c1 All correspondence to: Randall S. Prather, 162 Animal Science Research Center, University of Missouri-Columbia, Columbia, MO 65211. Tel: +1 (573) 882 6414. Fax: (573) 884 7827. e-mail: PratheR@Missouri.Edu
p1 Current address: Korea Institute of Bioscience and Biotechnology, Yusong, 305-600, Korea.