title: Differentially expressed genes in preimplantation human embryos: potential candidate genes for blastocyst formation and implantation.
abstract: OBJECTIVE
  The aim of this study was to determine which genes and gene pathways are differentially expressed when comparing human blastocysts with cleavage-stage embryos.
  
  
  METHODS
  We individually assessed gene expression in preimplantation human embryos at cleavage (n = 3) and blastocyst (n = 3) stages. Gene expression patterns were then validated in publically available datasets and then independently validated in vitro with additional human embryos using TaqMan gene expression assays. Immunolocalization studies were conducted to identify protein expression in intact blastocyst-stage embryos.
  
  
  RESULTS
  Compared to cleavage-stage embryos, blastocyst-stage embryos differentially expressed 51 genes (p < 0.001), with overrepresentation in amoebiasis pathways and pathways in cancer. Of these 51 genes, 21 were found to be independently validated in a separate, publically available dataset, with a substantial agreement with our initial findings (κ = 0.8). In an independent set of cleavage- and blastocyst-stage embryos, we validated that six of eight tested genes were differentially expressed (p < 0.05) by RT-qPCR. Immunofluorescence studies documented the presence of two studied proteins in the trophectoderm of blastocyst-stage embryos.
  
  
  CONCLUSIONS
  Differentially expressed genes may be implicated in the invasion and proliferation of the early embryo. Our research highlights specific genes that may be further studied for their role in the implantation process and additionally raises questions about localized gene and/or protein expression in the trophectoderm, which could affect protocols for, and interpretation of, trophectoderm biopsies performed in in vitro fertilization cycles.
authors.affiliation: Department of Obstetrics and Gynecology, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, PFP 31330, Iowa City, IA, 52242, USA. erika-munch@uiowa.edu.
authors.forename: Erika M
authors.initials: EM
authors.lastname: Munch
authors.affiliation: Department of Obstetrics and Gynecology, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, PFP 31330, Iowa City, IA, 52242, USA.
authors.forename: Amy E
authors.initials: AE
authors.lastname: Sparks
authors.affiliation: Department of Obstetrics and Gynecology, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, PFP 31330, Iowa City, IA, 52242, USA.
authors.forename: Jesus
authors.initials: J
authors.lastname: Gonzalez Bosquet
authors.affiliation: Department of Molecular and Integrative Physiology, The University of Kansas School of Medicine, Kansas City, KS, 66160, USA.
authors.forename: Lane K
authors.initials: LK
authors.lastname: Christenson
authors.affiliation: Department of Obstetrics and Gynecology, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, PFP 31330, Iowa City, IA, 52242, USA.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Devor
authors.affiliation: Department of Obstetrics and Gynecology, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, PFP 31330, Iowa City, IA, 52242, USA.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Van Voorhis
mesh_terms: D001755:Blastocyst / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics*; D010064:Embryo Implantation / Q000235:genetics; D047108:Embryonic Development / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D009418:S100 Proteins / Q000235:genetics
chemical_list: D002135:Calcium-Binding Proteins; D009418:S100 Proteins; C462950:S100A14 protein, human; C000589580:S100A16 protein, human
keywords: Blastocyst; Cancer; Embryo culture; Gene expression; Preimplantation embryo