|Matteri, Robert - Bob|
Submitted to: Zygote
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/25/2001
Publication Date: N/A
Citation: N/A Interpretive Summary: An increase of only one piglet weaned per litter would have an estimated value of 200-300 million dollars to the U.S. swine industry under current market conditions. A major obstacle in increasing piglet production is the high rate of embryonic loss. Approximately 30% of pig embryos are lost during the first month of pregnancy. Communication between the embryo and mother is an important factor for successful pregnancy. A class of embryonic proteins called pregnancy-associated glycoproteins (PAG) are likely to participate in these interactions; however, the production of PAG in early pig embryos has not been studied. We have established methods for detecting the production of two pig PAGs, PAG-1 and PAG-2, and demonstrated that these compounds are produced at early stages of development coinciding with periods of interaction between the embryo and placenta. The present study makes further studies possible in which the importance of PAG in embryonic survival can be examined. The results will be utilized by scientists with interests in the improvement of pig litter size and early embryo development.
Technical Abstract: The objective of this study was to determine whether porcine PAG (poPAG) genes are expressed in embryos as they develop from the one-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 fertilization, after in vitro fertilization of in vitro-matured oocytes, or following parthenogenic activation of in vitro- matured oocytes. The presence of PAG transcripts was determined at the one-, two-, and four-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 yas the four-cell stage. Our study revealed that poPAG 1 and 2 genes are expressed as early as the compact morula stage and four-cell stage, respectively, in normal embryos and in parthenogenetically-derived blastocysts. These results qualify the PAG genes as potential candidates for markers of developmental competence.