The expression and potential function of bone morphogenetic proteins 2 and 4 in bovine trophectoderm

RNA was isolated from day 17 bovine conceptuses and CT1 cells. After RT-PCR, amplified products were cloned and sequenced. In other studies CT1 cells were treated with BMP2 or 4 at various concentrations and effects on cell viability, cell differentiation and abundance of IFNT and CSH1 mRNA were evaluated.Transcripts for BMP2 and 4 were detected in bovine conceptuses and CT1 cells. Also, transcripts for each BMP receptor were detected in conceptuses and CT1 cells. Transcripts for NOG were detected in conceptuses but not CT1 cells. Cell proliferation was reduced by BMP4 but not BMP2 supplementation. Both factors reduced IFNT mRNA abundance but had no effect on CSH1 mRNA abundance in CT1 cells.The BMP2/4 ligand and receptor system presides within bovine trophectoderm prior to uterine attachment. BMP4 negatively impacts CT1 cell growth and both BMPs affect IFNT mRNA abundance.Bone morphogenetic proteins (BMPs) are part of the transforming growth factor-β (TGFβ) superfamily of paracrine factors [1,2]. The BMPs mediate various physiological and developmental processes, including placental development [3]. The BMP4 family of factors, which include BMPs 2 and 4, appear to be especially important in placental development. In the mouse, conceptuses lacking BMP4 undergo developmental arrest at days 6.5-9.5 and lack mesoderm and placental vasculature [4-6]. Mesoderm formation also is absent in mice lacking Bmpr2, the Type II receptor for BMP4 [7]. Interestingly, Bmpr2 null mice have a more severe phenotype than mice lacking BMP4, suggesting the partial rescue of the BMP4 null phenotype by other BMPs, such as BMP2 [8].Bone morphogenetic proteins 2 and 4 also regulate trophoblast lineage development and differentiation. Trophoblast development from human embryonic stem cells is induced by BMP2 and 4 [9,10]. In cattle, BMP4 supplementation improves the formation of trophoblast cell outgrowths from blastocysts [11]. Moreover, trophoblast cell lines generated from these outgrowths