Expression of Growth Factor Ligand and Their Receptor mRNAs in Bovine Ova during In Vitro Maturation and after Fertilization In Vitro.

Abstract

ABSTRACT. We analyzed the expression of mRNAs for growth factor [epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), basic fibroblast growth factor (bFGF) and platelet-derived growth factor A chain (PDGF-A)] and their receptor (R) by reverse transcriptionpolymerase chain reaction in bovine ova during oocyte maturation in vitro (0-21 hr) and after fertilization in vitro (6-144 hr: zygotes to blastocysts). Transcripts for EGF were not found before fertilization. Transcripts for IGF-I were present in immature oocytes immediately after collection and in embryos from the 2-cell stage onward. Transcripts for bFGF were present in all stages of oocyte maturation and after fertilization up to the 16-cell stage. Transcripts for PDGF-A were present in all stages of oocyte maturation and after fertilization up to the 2-cell stage. Transcripts for ErbB3 (a member of the EGF-R subfamily), and bFGF-R were present in all stages of oocyte maturation, after fertilization up to the 2-cell stage, and the blastocyst stage. Transcripts for IGF-I-R and PDGF-Rα were present in all stages of oocyte maturation and embryo development. The results of this study showed that eight different messages for growth factor and their receptor were detectable in bovine ova during oocyte maturation and/or after fertilization in vitro and their expression patterns were the gene-specific rather than the developmental stage of bovine ova. -KEY WORDS: bovine ova, growth factor, growth factor receptor, mRNA, RT-PCR.

Increased apoptosis in bovine blastocysts exposed to high levels of IGF1 is not associated with downregulation of the IGF1 receptor

“…Gene expression of the IGF1 ligand has been detected from the zygote to the blastocyst stage in mouse embryos (Stojanov & O'Neill 2001) and immunolocalisation studies confirmed its presence, revealing a higher expression in the ICM than in the TE cells (Stojanov & O'Neill 2001). In contrast, early studies had reported the presence of mRNA for IGF1 ligand in preimplantation bovine embryos (Watson et al 1992, Yoshida et al 1998, Lonergan et al 2000, but subsequent experiments did not confirm these observations (Yaseen et al 2001, Bertolini et al 2002, Ponsuksili et al 2002, Moore et al 2007, Warzych et al 2007, Wang et al 2009). This indicates an active autocrine IGF1 circuit in mice compared with cattle, similar to that of the ovary .…”

Developmental and molecular correlates of bovine preimplantation embryos

“…The use of different culture media had no effect on blastocyst formation. Expression of Igf-2r is detectable at all stages of embryonic development in bovine embryos (Watson et al 1992, Yoshida et al 1998, Yaseen et al 2001. It has been postulated that insulin-like growth factors play a role as a survival factor in preimplantation bovine embryos (Yaseen et al 2001).…”

The role of IGF1 in the in vivo production of bovine embryos from superovulated donors

“…The IGF1 receptor has been localized in bovine oocytes, cumulus cells and in both granulosa and theca cells (Yoshida et al 1998, Perks et al 1999, Armstrong et al 2001, Schams et al 2002, Nuttinck et al 2004, Sudo et al 2007. In vitro studies have shown that IGF1 synergizes with FSH to regulate the aromatase activity of granulosa cells (Spicer et al 2002).…”