Identification of a tektin‐like protein associated with neurofilaments in the developing chick nervous system

A 160‐kD polypeptide, which is recognized by an affinity‐purified polyclonal antibody to the 55‐kD tektin‐A polypeptide from sea urchin sperm flagellar microtubules, is associated with neurofilaments in embryonic chick nerve cells. Antibodies to tektin‐A and monoclonal antibodies to the neurofilament triplet proteins colocalize to filaments in cultured nerve cells and to filaments in extracts of chick spinal cord, using indirect immunofluorescence microscopy and immunogold electron microscopy. The antigen reacting with anti‐tektin‐A in chick brain and spinal cord extracts has been identified as a 160‐kD polypeptide by SDS‐PAGE and has been shown to be distinct from the known neurofilament‐triplet proteins by two‐dimensional immunoblot analysis. These data suggest that a unique protein with limited sequence homology to tektin‐A is a component of the neuronal cytoskeleton and is incorporated into or associated with neurofilaments.