Global gene expression of the inner cell mass and trophectoderm of the bovine blastocyst
1 Department of Animal Sciences and D.H. Barron Reproductive and Perinatal Biology Research Program, PO Box 110910, Gainesville, FL, 32611-0910, USA
2 Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, 32611-0910, USA
3 Kyushu-Okinawa Agricultural Research Center, National Agriculture and Food Research Organization, Kumamoto, Japan
4 Laboratory of Developmental Genetics, Institute of Medical Science, University of Tokyo, Tokyo, Japan
5 Human Genome Center, Institute of Medical Science, University of Tokyo, Tokyo, Japan
6 Departamento de Reprodução Animal e Radiologia Veterinária, Faculdade de Medicina Veterinária e Zootecnia, UNESP, Botucatu, São Paulo, Brasil
BMC Developmental Biology 2012, 12:33 doi:10.1186/1471-213X-12-33Published: 6 November 2012
The first distinct differentiation event in mammals occurs at the blastocyst stage when totipotent blastomeres differentiate into either pluripotent inner cell mass (ICM) or multipotent trophectoderm (TE). Here we determined, for the first time, global gene expression patterns in the ICM and TE isolated from bovine blastocysts. The ICM and TE were isolated from blastocysts harvested at day 8 after insemination by magnetic activated cell sorting, and cDNA sequenced using the SOLiD 4.0 system.
A total of 870 genes were differentially expressed between ICM and TE. Several genes characteristic of ICM (for example, NANOG, SOX2, and STAT3) and TE (ELF5, GATA3, and KRT18) in mouse and human showed similar patterns in bovine. Other genes, however, showed differences in expression between ICM and TE that deviates from the expected based on mouse and human.
Analysis of gene expression indicated that differentiation of blastomeres of the morula-stage embryo into the ICM and TE of the blastocyst is accompanied by differences between the two cell lineages in expression of genes controlling metabolic processes, endocytosis, hatching from the zona pellucida, paracrine and endocrine signaling with the mother, and genes supporting the changes in cellular architecture, stemness, and hematopoiesis necessary for development of the trophoblast.