Neurofilament alpha-internexin/NF66

Alpha-Internexin is a ~66 kDa Class IV intermediate filament subunit expressed very early in neuronal development. It is related to but distinct from the better known neurofilament triplet proteins, NF-L, NF-M, and NF-H, having similar protein sequence motifs and a similar intron organization. Many classes of mature neurons contain alpha-internexin in addition to NF-L, NF-M, and NF-H. In some mature neurons alpha-internexin is the only neurofilament subunit expressed. Antibodies to internexin are therefore unique probes to study and classify neuronal types and follow their processes in sections and in tissue culture. In addition, the very early developmental expression of alpha-internexin means its presence is an early and convenient diagnostic feature of neuronal progenitors cells and other cell committed to the neuronal lineage. The use of antibodies to this protein in the study of brain tumors has not been examined to date, but is likely to be of interest.