Journal of Neuroscience, Vol 9, 454-465, Copyright © 1989 by Society for Neuroscience
Monoclonal antibodies differentiate neurofilament and glial filament proteins in the goldfish visual pathway: probes for monitoring neurite outgrowth from retinal explants
PS Jones, P Tesser, J Borchert and N Schechter
Department of Biochemistry, State University of New York, Stony Brook 11794.
The expression of the neurofilament proteins of the goldfish visual pathway
reflects the degeneration and regeneration of the optic nerve after nerve
crush. To monitor these processes, monoclonal antibodies (mAb) were
generated to the intermediate filament proteins of this pathway. The
predominant goldfish visual pathway intermediate filament proteins have a
molecular weight of 58K and can be separated into 4 isoelectric variants, 2
of which are neuronal (ON1 and ON2) and 2 of which are non-neuronal (ON3
and ON4). The specificities of the mAbs were characterized biochemically
and histologically. Immunoblot analysis demonstrated that 2 of the
antibodies reacted specifically with the neurofilament proteins (ON1/ON2)
and another antibody reacted specifically with the glial filament proteins
(ON3/ON4) and with a 48K optic nerve protein of non-neuronal origin.
Chymotrypsin digestion of the ON proteins and immunoblotting of the
resulting fragments showed that the anti-ON1/ON2 mAbs were directed toward
the variable domains of the filament proteins. In contrast, the
anti-ON3/ON4 mAb was directed toward the 40K chymotrypsin-resistant region
of the glial filament proteins containing the conserved intermediate
filament core. When sections of optic nerve tissue were incubated with
anti-ON1/ON2 or anti- ON3/ON4 mAbs, the staining resulted in either axonal
or glial patterns, respectively. In retina, after optic nerve crush,
anti-ON1/ON2 labeled retinal ganglion cells and Muller fibers. In contrast,
prior to optic nerve crush, only Muller fibers were labeled. One of the
neuronal- directed mAbs was used to decorate growing neurites from retinal
explants; anti-ON1/ON2 reactivity appeared in a time-dependent manner that
paralleled the expression of ON1/ON2 in vivo. Thus, the antibodies can
differentiate these 2 types of goldfish intermediate filament proteins and
can be used to monitor optic nerve regeneration in the goldfish visual
pathway both in vivo and in vitro.