title: Characterization of secreted proteins of 2-cell mouse embryos  cultured in vitro to the blastocyst stage with and without protein  supplementation.
abstract: OBJECTIVE
  To identify the secreted proteins of murine embryos grown in vitro.
  
  
  METHODS
  Two-cell mouse embryos (n=432) were randomly allocated to culture to the blastocyst stage in protein-free and in protein-supplemented (3 % BSA) media. Proteins were separated by SDS-PAGE; bands were visualized by coomassie staining, followed by in-gel trypsin digestion and liquid chromatography-tandem mass spectrometry. RT-PCR and confocal microscopy were used to confirm gene/protein expression in blastocysts.
  
  
  RESULTS
  Of all individually identified proteins, 34 and 23 were found in embryos cultured without and with BSA, respectively, and 20 were common. Identified proteins having an N-terminal secretory sequence or transmembrane domains located on the extracellular backbone were postulated as secreted proteins. Gene and protein expression for two selected molecules were confirmed. Functional analysis revealed over-represented processes related to lipid metabolism, cyclase activity, and cell adhesion/membrane functions.
  
  
  CONCLUSIONS
  This study provided evidence to further characterize secreted proteins by mouse embryos grown from the 2-cell to the blastocyst stage in vitro. Because of homology between murine and human, these results may provide information to be translated to the clinical setting.
authors.forename: Tanya
authors.initials: T
authors.lastname: Burch
authors.forename: Liang
authors.initials: L
authors.lastname: Yu
authors.forename: Julius
authors.initials: J
authors.lastname: Nyalwidhe
authors.forename: Jose A
authors.initials: JA
authors.lastname: Horcajadas
authors.forename: Silvina
authors.initials: S
authors.lastname: Bocca
authors.forename: R James
authors.initials: RJ
authors.lastname: Swanson
authors.forename: Sergio
authors.initials: S
authors.lastname: Oehninger
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology*; D003470:Culture Media / Q000737:chemistry; D004622:Embryo, Mammalian / Q000187:drug effects / Q000378:metabolism*; D047108:Embryonic Development / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006801:Humans; D051379:Mice; D014176:Protein Biosynthesis / Q000235:genetics*; D011506:Proteins / Q000008:administration & dosage* / Q000737:chemistry
chemical_list: D003470:Culture Media; D011506:Proteins