title: Thyroid hormones alter the transcriptome of in vitro-produced bovine blastocysts.
abstract: Thyroid hormones (THs) have been shown to improve in vitro embryo production in cattle by increasing blastocyst formation rate, and the average cell number of blastocysts and by significantly decreasing apoptosis rate. To better understand those genetic aspects that may underlie enhanced early embryo development in the presence of THs, we characterized the bovine embryonic transcriptome at the blastocyst stage, and examined differential gene expression profiles using a bovine-specific microarray. We found that 1212 genes were differentially expressed in TH-treated embryos when compared with non-treated controls (>1.5-fold at P < 0.05). In addition 23 and eight genes were expressed uniquely in control and treated embryos, respectively. The expression of genes specifically associated with metabolism, mitochondrial function, cell differentiation and development were elevated. However, TH-related genes, including those encoding TH receptors and deiodinases, were not differentially expressed in treated embryos. Furthermore, the over-expression of 52 X-chromosome linked genes in treated embryos suggested a delay or escape from X-inactivation. This study highlights the significant impact of THs on differential gene expression in the early embryo; the identification of TH-responsive genes provides an insight into those regulatory pathways activated during development.
authors.affiliation: Department of Biomedical Sciences,University of Guelph,Guelph,ON N1G 2W1,Canada.
authors.forename: Fazl A
authors.initials: FA
authors.lastname: Ashkar
authors.affiliation: Department of Biomedical Sciences,University of Guelph,Guelph,ON N1G 2W1,Canada.
authors.forename: Tamas
authors.initials: T
authors.lastname: Revay
authors.affiliation: Department of Biomedical Sciences,University of Guelph,Guelph,ON N1G 2W1,Canada.
authors.forename: NaYoung
authors.initials: N
authors.lastname: Rho
authors.affiliation: Department of Biomedical Sciences,University of Guelph,Guelph,ON N1G 2W1,Canada.
authors.forename: Pavneesh
authors.initials: P
authors.lastname: Madan
authors.affiliation: Faculté des Sciences de l'Agriculture et de l'Alimentation,Département des Sciences Animales,Pavillon INAF,Centre de Recherche en Biologie de la Reproduction (CRBR),Université Laval,Québec,Canada.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dufort
authors.affiliation: Faculté des Sciences de l'Agriculture et de l'Alimentation,Département des Sciences Animales,Pavillon INAF,Centre de Recherche en Biologie de la Reproduction (CRBR),Université Laval,Québec,Canada.
authors.forename: Claude
authors.initials: C
authors.lastname: Robert
authors.affiliation: Department of Biomedical Sciences,University of Guelph,Guelph,ON N1G 2W1,Canada.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Favetta
authors.affiliation: Department of Biomedical Sciences,University of Guelph,Guelph,ON N1G 2W1,Canada.
authors.forename: Chris
authors.initials: C
authors.lastname: Schmidt
authors.affiliation: Department of Biomedical Sciences,University of Guelph,Guelph,ON N1G 2W1,Canada.
authors.forename: W Allan
authors.initials: WA
authors.lastname: King
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002417:Cattle; D047108:Embryonic Development / Q000187:drug effects / Q000235:genetics; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods / Q000662:veterinary; D020869:Gene Expression Profiling / Q000379:methods / Q000662:veterinary; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods / Q000662:veterinary; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D013963:Thyroid Hormones / Q000494:pharmacology*; D059467:Transcriptome / Q000187:drug effects*
chemical_list: D013963:Thyroid Hormones
keywords: Blastocyst; Bovine embryo; Embryonic transcriptome; Gene expression; Thyroid hormones