Morphological analysis of intranuclear bFGF

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This project was performed to investigate the function of intranuclear bFGF in developing cerebellar Purkinje cell, regenerating hepatocyte and myoblast.1.Development of Purkinje cells with bFGFGOn postnatal day 7, immunoreactive Purkinje cells were identified throught cerebellar cortex, and they expressed bFGF-like immunoreactivity mainly in the apical cytoplasm and proximal dendrites. From postnatal day 14 to postnatal day 28, bFGF-like immunoreactivity was noted throughout the cytoplasm and nuclei of Purkinje cells. Statistical analysis showed that Purkinje cells with nuclear bFGF-immunoreaction peaked on postnatal day 21. After postnsl day 42, Purkinje cells with nuclear nFGF showed a marked decrease in number.2.Regenerating hepatocytes with bFGFImmunoblot experiments and ELISA showed a transient increase in high-moleculae-weight froms of bFGF in the nuclear subcellular fraction of regenerating liver 48h after partial hepatectomy. By light microscopy, bFGF and PCNA immunoreactiviti … More es were detected in the nuclei of hepatectomy. Electron microscopy demonstrated bFGF-like immunoreactivity mainly in the nuclear euchromatin and rarely in the heterochromatin or nucleoli of regenerating hepatocytes. These results suggest an important role of the high-molecular-weight forms of bFGF in hepatocyte proliferation and mitosis.3.Myogenic activity of bFGFThe localization of bFGF-like immunoreactivity in the masseter muscle of dystrophic mdx mice on postnatal day 28 was investigated by immunoblot analysis and electron microscopy. By electron microscopy, bFGF immunoreactivity was detected in small regenerating myocytes, and mature myocytes with densely packed myofilaments did not exhibit bFGF immunoreactivity. The effect or bFGF and platelet factor 4 (PF4), which blocks the binding of bFGF to its receptor, on myoblast culture was investigated. bFGF stimulated myoblast proliferation and myotube formation, but PF4 inhibited these effects of bFGF.The biospecific interaction analysis (BIA) core system showed that the myoblast membrane fraction contains bFGF-binding elements which are blocked by PF4. Less