Tyrosine kinase A, C and fibroblast growth factor-2 receptors in bovine embryos cultured in vitro.

Neurotrophins and basic fibroblast growth factor are ligands of tyrosine kinase receptors, though they bind to different tyrosine kinase receptor classes. Neurotrophins bind to receptor tyrosine kinase class VII, Trk receptor family, while basic fibroblast growth factor binds to receptor tyrosine kinase class IV, FGF receptor family. The mammalian uterine tract immunolocalizes neurotrophins and bFGF; therefore their cognate receptors might exert a role during embryonic development. Using RT-PCR, we found mRNA for p75(NTR) TrkA, TrkC and FGFr2 throughout the early bovine embryonic development in vitro. Immunofluorescent staining, assessed by confocal microscopy, showed the expression of TrkA and TrkC proteins in oocytes and all embryonic stages analyzed. We have provided a novel description of TrkA and TrkC proteins, and TrkA, TrkC, p75(NTR) and FGFr2 mRNA expression throughout mammalian embryonic development. This work may help to design future research with neurotrophins in bovine embryo culture and embryonic stem cells.