Immunochemical and molecular characterization of GBC4 as a tanycyte-like cell line derived from grouper brain.

A clonal cell line, GBC4, derived from grouper (Epinephelus coioides) brain is proposed to represent an immature astroglial cell line because it expresses glial fibrillary acidic protein (GFAP), cytokeratin and vimentin. In teleost brain, tanycytes are the most abundant GFAP-expressing cell type, suggesting that GBC4 cells are derived from tanycytes. To test this hypothesis, protein and mRNA expression profiles of GBC4 cells were evaluated. We detected protein and/or mRNA expression of aromatase B, brain lipid binding protein, connexin43 protein, glutamine synthetase, S100 protein and Sox2. These proteins/mRNAs are also expressed in fish tanycytes. GBC4 cells also contained oligodendroglia proteins, including A2B5, galactocerebroside, myelin basic protein, proteolipid protein and platelet-derived growth factor receptor alpha as well as certain neuronal protein markers such as connexin35 protein and tyrosine hydroxylase. Our results indicate that GBC4 cells may be multipotent neural progenitor cells similar to tanycytes. Because GBC4 expresses several neural-specific genes, this line will be useful for studies on gene expression/regulation and neural development.