Meteorin is a novel secreted protein that is expressed by undifferentiated neural and glial progenitors, and astrocytes. Its name derives from its ability to generate glial cells with long meteor-like tails. Mouse meteorin is synthesized as a 291 amino acid (aa) precursor that contains a 270 aa mature region. It contains eight cysteines with no identifiable domains or N-linked glycosylation sites. Mature mouse meteorin is 82% and 77% aa identical to human and bovine meteorin, respectively.