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Parlow, MH, Bolender, DL, Kokan-Moore, NP and Lough, J (1991) Localization of bFGF-like proteins as punctate inclusions in the preseptation myocardium of the chicken embryo. Dev. Biol. 146:139-47

Immunocytochemistry has been employed to map the appearance of bFGF-like proteins in precardiac and preseptation myocardial cells between stages 6 and 15 of chicken embryogenesis. Stage 6 embryos exhibited no staining, with the exception of a subtle signal in endoderm cells. At subsequent stages, staining was observed only in cells of the developing myocardium, first appearing at the time of heart tube fusion (stage 9+) as punctate cytoplasmic aggregates. While the expression of bFGF-like antigen was temporally similar to that of myosin heavy chain, their staining patterns differed in that bFGF-like proteins were nonsarcomeric and did not extend into the inflow or outflow tracts. Western blotting of heparin agarose affinity-isolated proteins from stage 15 hearts revealed an antigen migrating at approximately 19 kDa. In contrast with the unique localization of bFGF-like proteins in myocardial cells, FGF receptor (FGFR) staining was widely distributed in the embryo; however, concentrated deposits of FGFR were detected in endothelial and myocardial cells, which diminished in the myocardium but not in the endothelium by stage 15. These results suggest that FGF-like proteins may have autocrine and/or paracrine functions during early cardiac morphogenesis.

PubMed

Animals; Chick Embryo; Endothelium, Vascular/chemistry; Endothelium, Vascular/embryology; Fibroblast Growth Factor 2/analysis; Fibroblast Growth Factor 2/metabolism; Fibroblast Growth Factor 2/physiology; Heart/embryology; Inclusion Bodies/chemistry; Inclusion Bodies/metabolism; Molecular Weight; Myocardium/chemistry; Myocardium/metabolism; Myosins/immunology