Journal of Neuroscience, Vol 9, 876-883, Copyright © 1989 by Society for Neuroscience
Characterization of a partial cDNA clone for the NILE glycoprotein and identification of the encoded polypeptide domain
JT Prince, N Milona and WB Stallcup
La Jolla Cancer Research Foundation, California 92037.
A partial cDNA clone [2.4 kilobase (kb)] for the nerve growth factor-
inducible large external (NILE) glycoprotein was selected from a lambda gt
11 expression library constructed using mRNA from PC 12 cells. A 0.2 kb
subclone (pNILE-1B) was used for Northern blot analysis of NILE message
present in 2 NILE-positive neuronal cell lines and 2 NILE- negative glial
cell lines. pNILE-1B hybridizes with components of 6.8 and 2.0 kb in the 2
neuronal cell lines but fails to show hybridization with any components in
the 2 glial cell lines. Only the 6.8 kb species would be large enough to
code for the NILE polypeptide. A rabbit antiserum was prepared against the
NILE-beta-galactosidase fusion protein produced by the NILE clone. This
antiserum (anti-NILE-beta-gal) immunoprecipitates NILE glycoprotein from
neuronal cell lines, further confirming the authenticity of the NILE cDNA
clone. The epitope recognized by anti-NILE-beta-gal is contained in an 85
kDa tryptic fragment from the phosphorylated carboxy terminus of NILE. The
160 kDa tryptic fragment containing the amino terminus is not recognized by
anti-NILE-beta-gal. Both immunoprecipitation and immunofluorescence
experiments indicate that the anti-NILE-beta-gal epitope is not exposed on
the cell surface but is accessible only after cells are treated with
detergent. The cytoplasmic nature of the determinant is also indicated by
its absence on a truncated, soluble form of NILE released from cells
(possibly by a proteolytic mechanism) into the medium.(ABSTRACT TRUNCATED
AT 250 WORDS)