Journal of Neuroscience, Vol 5, 369-378, Copyright © 1985 by Society for Neuroscience
Neuron-specific interactions with two neurite-promoting fragments of fibronectin
SL Rogers, JB McCarthy, SL Palm, LT Furcht and PC Letourneau
Proteolytic fragments of fibronectin were used to identify regions of the
molecule that support neurite extension and to investigate further the
differential behavior of central and peripheral nervous system neurons in
response to fibronectin (Rogers, S. L., P. C. Letourneau, S. L. Palm, J. B.
McCarthy, and L. T. Furcht (1983) Dev. Biol. 98: 212- 220). Fibronectin
fragments with differing biological activities were produced by proteolytic
digestion with trypsin and cathepsin D and sequential affinity
chromatography on gelatin-agarose and heparin- Sepharose. The resulting
fragments (described by Smith, D. E., D. F. Mosher, R. B. Johnson, and L.
T. Furcht (1982) J. Biol. Chem. 257: 5831- 5838; Smith, D. E., and L. T.
Furcht (1982) J. Biol. Chem. 257: 6518- 6523 included an NH2-terminal
27,000-dalton peptide that weakly binds heparin, a 46,000-dalton
gelatin-binding fragment, a series of fragments (80,000 to 125,000 daltons)
from the center of the molecule containing previously described
cell-binding activity, two major peptides of Mr = 33,000 and 66,000 that
bind heparin strongly and are thought to originate from the A and B chains,
respectively, of plasma fibronectin, and a 31,000-dalton COOH-terminal
peptide containing a free sulfhydryl from the A chain of the molecule.
Tissue culture dishes were treated with these proteolytic preparations, and
dissociated embryonic chick peripheral (PNS) and central nervous system
(CNS) cells were cultured on each experimental substratum in serum-free
medium. The fibronectin fragments were evaluated for ability to promote
cell attachment, neurite initiation, and maintenance of neurite growth. The
27,000-, 46,000-, and 31,000-dalton preparations did not promote cell
attachment or neurite extension. Both PNS and CNS neurons attached to and
extended stable neurites upon the COOH-terminal heparin-binding preparation
containing the 33,000- and 66,000-dalton peptides. A differential response
of the neurons to the 80,000- to 125,000-dalton "cell-binding" peptides was
observed: whereas PNS neurons maintained neuritic growth on this
preparation for at least 48 hr, CNS neurons extended neurites during the
first 24 hr of culture but, by 48 hr, withdrew these neurites and became
increasingly clumped. On the basis of (1) the observed neuronal responses
to the heparin binding and "cell binding" regions, and (2) the different
ligand-binding properties of these regions, we propose that cell attachment
and neurite extension can be mediated and/or modulated by two separate
regions of fibronectin and that cellular response to the intact molecule
may involve multivalent interactions.
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