The Journal of Neuroscience, January 1, 1998, 18(1):174-183
Neurons Produce a Neuronal Cell Surface-Associated Chondroitin
Sulfate Proteoglycan
Cynthia
Lander,
Hong
Zhang, and
Susan
Hockfield
Section of Neurobiology, Yale University School of Medicine, New
Haven, Connecticut 06520-8001
Monoclonal antibody Cat-315 recognizes a chondroitin sulfate
proteoglycan (CSPG) expressed on the surface of subsets of neurons in
many areas of the mammalian CNS (). The cell
type-specific expression exhibited by the Cat-315 CSPG and other
perineuronal net CSPGs imparts a distinct molecular surface identity to
a neuron (; ). The cell
type(s) producing these surface-associated proteins and yielding this
cellular diversity has remained in question. The expression of the
Cat-315 CSPG in primary rat cortical cultures has permitted an
examination of the cellular source of the Cat-315 antigen, as well as a
determination of its spatial relationship to the neuronal surface.
Live-cell labeling of primary neuronal cultures demonstrates that the
Cat-315 CSPG is on the extracellular surface of neurons. Furthermore,
extraction experiments demonstrate that the Cat-315 CSPG lacks a
transmembrane domain and that the entire molecule is extracellular and,
therefore, can be considered a constituent of brain extracellular
matrix. Several lines of evidence indicate that neurons with cell
surface staining produce the Cat-315 CSPG. First, neurons with cell
surface staining also show intracellular Cat-315 immunoreactivity.
Second,
-xyloside or monensin, reagents that inhibit the synthesis
and transport of CSPGs, increase intracellular Cat-315 immunoreactivity
within neurons that express cell surface Cat-315 immunoreactivity.
Third, double labeling with Cat-315 and a polyclonal antibody for the
Golgi complex demonstrates a precise colocalization of the
intracellular Cat-315 immunoreactivity with the Golgi. Together, these
observations demonstrate that neurons contribute to the extracellular
matrix of brain and that the Cat-315 CSPG is produced by the neurons
that carry Cat-315 cell surface immunoreactivity.
Key words:
perineuronal net; brain extracellular matrix; neuronal subsets; rat cortex; primary neuronal cultures; glycosaminoglycan
Copyright © 1998 Society for Neuroscience 0270-6474/98/181174-10$05.00/0