Expression and distribution of GAP-43 in human astrocytes in culture.
By combining mRNA analysis and immunocytochemistry, we investigated the expression of the growth associated protein 43 (GAP-43) in enriched populations of astrocytes, obtained from mixed cultures of human fetal brains. Total cellular RNA was extracted from cell pellets and reverse transcribed into cDNA; cDNA was subjected to PCR amplification using primers specific for GAP-43 and PCR products were separated through polyacrylamide gels. Double immunofluorescence staining was performed on dissociated cell cultures using antibodies to glial fibrillary acidic protein (GFAP) and to GAP-43. Results showed that both transcription and translation for GAP-43 occur in cultured astrocytes. GAP-43 immunoreacting material was detected in the cell processes and diffusely in the cytoplasm of GFAP-positive astrocytes, during early stages of maintenance in vitro. In older cultures, GAP-43 immunoreactivity persisted in a large percentage of cells, with a tendency to accumulate in perinuclear areas. These observations provide evidence that GAP-43 is not restricted to neuronal cells. The close spatial association with cytoskeletal constituents, as observed in astrocytes, suggests a role for this protein in the control of cell shape, motility and adhesion processes.
D001253:Astrocytes / Q000378:metabolism*; D001483:Base Sequence; D002448:Cell Adhesion; D002478:Cells, Cultured; D019922:GAP-43 Protein; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D016900:Neurofilament Proteins / Q000096:biosynthesis*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis
D019922:GAP-43 Protein; D005904:Glial Fibrillary Acidic Protein; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; D012333:RNA, Messenger