Structural similarities and differences between neurofilament proteins from five different species as revealed using monoclonal antibodies.

Neurofilament (NF) proteins isolated from human, rabbit, rat, and chicken spinal cord white matter were immunoblotted with monoclonal antibodies (MAbs) raised to bovine NF immunogens. The aim of these experiments was to test the degree of epitope conservation among NF proteins from different vertebrate species. In so doing, the validity of using antibodies raised to NF from one species (cow) for detecting NF proteins of other species was also tested. The MAbs used for these experiments were characterized using bovine NFs to define polypeptide specificity, the approximate location of epitopes within each NF polypeptide, and the effects on antibody recognition of the presence or absence of phosphorylated residues in these polypeptides (see Carden et al., 1985). Our findings indicate that epitopes located in the alpha-helical core domains of NF-H, NF-M, and NF-L are distinct from each other, yet are strongly conserved among the different species. Epitopes located in the noncore or peripheral domains of the NF polypeptides show variable degrees of cross-species preservation. For example, all epitopes in the peripheral domains of bovine NF-H that require the presence of phosphate groups for recognition (phosphorylation dependent) are widely expressed in all species studied. Many phosphorylation-dependent epitopes of bovine NF-H are also present in bovine NF-M, as well as in NF-H of non-bovine species. In addition, epitopes in the peripheral domain of NF-H that require dephosphorylation of NF polypeptides for recognition (dephosphorylation dependent) are also found in NF-H of other mammalian species but not in NF-H of chicken.(ABSTRACT TRUNCATED AT 250 WORDS)