title: Aggregation of bovine cloned embryos at the four-cell stage stimulated gene expression and in vitro embryo development.
abstract: Pre-implantation embryos produced by somatic cell nuclear transfer (SCNT) have varied developmental potentials. The majority of SCNT blastocysts do not develop to term, and the mechanisms inhibiting development are still largely unknown. Aggregation of cloned embryos has been attempted to compensate for the developmental deficiency of individual cloned embryos. In this report, we investigated the impact of aggregation of bovine cloned embryos at the four-cell stage on in vitro development and gene expression of the embryos. Cell numbers and development rate of aggregated (NTagg) and non-aggregated (NT) blastocysts were characterized and compared. The blastocyst formation after aggregation was modeled using the binominal distribution. The results indicate that aggregation enhances the blastocyst formation but does not increase the overall blastocyst rate. Additionally, utilizing microarray gene chip analysis 8.8% of 8,059 genes analyzed were differentially expressed between NTagg and NT blastocysts, with more than 80% of the differentially expressed genes up-regulated in the NTagg blastocysts. Up-regulated genes include those involved in transcription, biosynthesis and signaling such as TDGF1, HNFA, CAV1, GLU5, and CD81. Our results indicate that aggregation of bovine cloned embryos at an early stage promotes the in vitro development of the resulting pre-implantation embryos.
authors.affiliation: Viagen Inc., Austin, Taxas 78732, USA. wenli.zhou@viagen.com
authors.forename: Wenli
authors.initials: W
authors.lastname: Zhou
authors.forename: Tianhao
authors.initials: T
authors.lastname: Xiang
authors.forename: Shawn
authors.initials: S
authors.lastname: Walker
authors.forename: Ronald V
authors.initials: RV
authors.lastname: Abruzzese
authors.forename: Earl
authors.initials: E
authors.lastname: Hwang
authors.forename: Vicki
authors.initials: V
authors.lastname: Farrar
authors.forename: Brian
authors.initials: B
authors.lastname: Findeisen
authors.forename: Sanaz
authors.initials: S
authors.lastname: Sadeghieh
authors.forename: Fernando
authors.initials: F
authors.lastname: Arenivas
authors.forename: Shu-Hung
authors.initials: SH
authors.lastname: Chen
authors.forename: Irina
authors.initials: I
authors.lastname: Polejaeva
mesh_terms: D000818:Animals; D002417:Cattle; D002449:Cell Aggregation / Q000502:physiology; D004622:Embryo, Mammalian / Q000196:embryology / Q000378:metabolism*; D047108:Embryonic Development / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D008954:Models, Biological; D053652:Nuclear Transfer Techniques; D020411:Oligonucleotide Array Sequence Analysis