Expression of growth factor ligand and receptor genes in the preimplantation bovine embryo

Abstract

The sensitive technique of mRNA phenotyping with the reverse transcription-polymerase chain reaction was employed to determine the patterns of gene expression for several growth factor ligand and receptor genes during bovine preimplantation development. Several thousand bovine embryos encompassing a developmental series from one-cell zygotes to hatched blastocysts were produced by the application of in vitro maturation, fertilization, and oviductal epithelial cell embryo coculture methods. Transcripts for transforming growth factor (TGF-alpha) and platelet-derived growth factor (PDGF-A) are detectable in all preimplantation bovine stages as observed in the mouse. Transcripts for TGF-beta 2 and insulin-like growth factor (IGF-II) and the receptors for PDGF-alpha, insulin, IGF-I, and IGF-II are also detectable throughout bovine preimplantation development, suggesting that these mRNAs are products of both the maternal and the embryonic genomes in the cow, whereas in the mouse they are present only following the activation of the embryonic genome at the two-cell stage. In contrast to the mouse embryo, IGF-I mRNA was detected within preimplantation bovine embryos. Basic fibroblast growth factor (bFGF) is a maternal message in the bovine embryo, since it is only detectable up until the eight-cell embryo stage. Bovine trophoblast protein (bTP) mRNA was detectable within day 8 bovine blastocysts. As was observed in the mouse, the transcripts for insulin, epidermal growth factor (EGF), or nerve growth factor (NGF) were not detectable in any bovine embryo stage. Analyses of this type should aid the development of a completely defined culture medium for the more efficient production of preimplantation bovine embryos.

Analysis of Igf2 and Igf2r Genes Expression by RT-PCR in Bovine Fetuses.

“…1). The low expression of the genes at the blastocyst stage was coincident with the report by Watson et al [11], who tested the gene expression with primers designed for human. On the other hand, in mice it is known that Igf2 and Igf2r genes are expressed throughout embryogenesis commencing at the 2-cell and 4 to 8-cell stages, respectively [13][14][15].…”

Effects of gas atmosphere, platelet-derived growth factor and leukemia inhibitory factor on cell numbers of rabbit embryos cultured in a protein-free medium

“…Further improvements in in vitro development may be dependent on the identification and addition of biological factors produced in the oviducts during embryo development. In fact, the expression of ligand and receptor genes for many growth factors in preimplantation stage embryos or in the oviduct supports the claim for their involvement during early embryonic development (Rappolee et al, 1988;Watson et al, 1992;Schulz and Heyner, 1993). Two such factors are platelet-derived growth factor (PDGF) and leukemia inhibitory factor (LIF).…”

Characterisation of endometrial gene expression and metabolic parameters in beef heifers yielding viable or non-viable embryos on Day 7 after insemination

“…During the pre-implantation period the embryo is dependent on secretions from the endometrial glands for its metabolic requirements. In this period IGFs are also expressed in the conceptus (Watson et al 1992) and the histotroph (Ko et al 1991). In the endometrium IGF has an effect on the secretion of early embryotrophic factors by the endometrial glands (Webb et al 1999).…”