73 PROTEOMIC ANALYSIS OF THE MAJOR CELLULAR PROTEINS OF BOVINE TROPHECTODERM CELL LINES DERIVED FROM IVP, PARTHENOGENETIC, AND NUCLEAR TRANSFER EMBRYOS: REDUCED EXPRESSION OF ANNEXIN I IN NUCLEAR TRANSFER-DERIVED CELL LINES

Abstract

Trophectoderm cell lines were established from 8-day in vitro cultured bovine embryos that were derived from the fertilization (IVF), somatic cell nuclear transfer (NT), or parthenogenetic activation (P) of in vitro-matured oocytes and from five 8-day-old in vivo (V) embryos. The most abundant cellular proteins of 2 V-, 16 NT-, 12 P-, and 13 IVF-derived cell lines were compared by 2-D gel electrophoresis and mass spectrometry; that is, the unaltered thiourea/urea extract of each cell culture was analyzed. One-hundred and eighteen in common protein spots were examined, and 95% were identified with significant scores from protein and gene database searches. Of the proteins detected and identified, actin and cytokeratin-8 were found to be the most abundant. Other prominently expressed cellular proteins were metabolic enzymes such as aldose reductase, phosphoglycerate mutase, enolase, triosephosphate isomerase, cytoskeletal interacting proteins transgelin and stratifin, antioxidant proteins peroxiredoxin 1 and anti-oxidant protein 2, and the calcium-dependent lipid-binding proteins annexin I and II. In comparative analysis of the 2-D gels, the NT-derived trophectoderm showed diminished annexin I expression in comparison to the IVF-derived trophectoderm. Since annexin I is abundantly expressed in the placenta and has functions important to the maintenance of placentation, the down-regulation of annexin I in the cultured NT trophectoderm may be related to the frequent failures of NT pregnancies.