Journal of Neuroscience, Vol 5, 1090-1101, Copyright © 1985 by Society for Neuroscience
Antibody against nerve growth factor-inducible large external (NILE) glycoprotein labels nerve fiber tracts in the developing rat nervous system
WB Stallcup, LL Beasley and JM Levine
The NILE (nerve growth factor-inducible large external) glycoprotein is a
230,000-dalton molecule found on the surface of PC12 cells. Immunologically
cross-reactive glycoproteins in the molecular weight range of 215,000 to
230,000 have been found on many types of neurons in culture. Using
immunohistochemical methods, we have shown that NILE- related glycoproteins
are present in neuronal fiber tracts of the developing rat brain. Antibody
against the NILE glycoprotein specifically labels processes that appear
identical to those recognized by antibodies against the neurofilament
triplet of proteins. These processes are clearly distinct from the radial
glial fibers recognized by antibody against the intermediate filament
protein vimentin. NILE glycoprotein is not distributed uniformly over the
entire neuronal surface but is concentrated on neurites and is much less
abundant on cell bodies. NILE-positive fiber tracts are first seen in the
spinal cord and rhombencephalon on embryonic day 11 and over the next 2
days appear in the mesencephalon and diencephalon. Staining in the
telencephalon is not seen until embryonic day 15. The appearance of NILE
immunoreactivity in these various regions closely parallels the appearance
of neurofilament polypeptides, suggesting that NILE-related glycoproteins
are present during the early phases of fiber tract formation. This idea is
supported by the finding that the NILE glycoprotein can be found
postnatally in parts of the nervous-system such as the cerebellar cortex
and olfactory bulb which undergo major histogenesis during the postnatal
period. In the cerebellum the appearance of NILE immunoreactivity in the
two major fiber zones, the molecular layer and the white matter, parallels
the development of the fiber structure of these layers. These findings
support tissue culture studies which suggest a role for the NILE
glycoprotein in mediating nerve fiber fasciculation.
