We have previously reported cloning of a novel gene that shares moderate homology with the glial cell line-derived neurotrophic factor (GDNF) receptor a (GFRα) family (SFN 2003 program no. 677.1). The gene contained a putative signal peptide at its N-terminus and shares conserved spacing of cystine residues which are also present in the GFRα receptors family. It was thus designated as GDNF receptor alpha-like (GRAL) gene. It appears to be localized specifically in the central nervous system of adult mouse. To investigate its potential biological function in vitro, we first screened a variety of cell lines to verify the expression of this gene. GRAL mRNA was only found in C17.2 cell line, a neural stem cell line, albeit at low levels. It was, however, absent in other cells examined, such as primary cultures of astrocytes, PC12, B104 and C6 cell lines. Following withdrawal of serum, the number of surviving C17.2 cells was markedly reduced. In contrast, the expression level of GRAL mRNA was significantly incr...