Nestin is a member of the class IV intermediate filament protein family which is expressed in neuronal stem cells (Lendahl et al., 1990). Nestin was originally identified as a result of the production of a series of monoclonal antibodies directed against epitopes expressed on formalin fixed embryo day 15 rat spinal cord (Hockfield et al., 1985)). One of these antibodies, called Rat 401, stained fibrous profiles in the developing nervous system, but not in the mature nervous system. By screening bacteriophage expression libraries with Rat 401, Lendahl et al. were able to isolate a cDNA encoding the protein to which Rat 401 antibody bound. The protein proved to be an unusual member of the intermediate filament family, containing an alpha-helical region homologous to that found in keratin and neurofilament subunits.
