Volume 17, Number 23,
Issue of December 1, 1997
pp. 9183-9193
Neuronal and Non-Neuronal Collapsin-1 Binding Sites in Developing
Chick Are Distinct from Other Semaphorin Binding Sites
Received June 13, 1997; revised Sept. 2, 1997; accepted Sept. 11, 1997.
Takuya Takahashi1, 2,
Fumio Nakamura1, and
Stephen M. Strittmatter1, 3
Departments of 1 Neurology, 2 Biology, and
3 Neurobiology, Yale University, New Haven, Connecticut
06520
The collapsin and semaphorin family of extracellular proteins
contributes to axonal path finding by repulsing axons and collapsing growth cones. To explore the mechanism of collapsin-1 action, we
expressed and purified a truncated collapsin-1-alkaline phosphatase fusion protein (CAP-4). This protein retains biological activity as a
DRG growth cone collapsing agent and saturably binds to DRG neurons
with low nanomolar affinity. Specific CAP-4 binding sites are present
on DRG neurons, sympathetic neurons, and motoneurons, but not on
retinal, cortical, or brainstem neurons. Outside the nervous system,
high levels of CAP-4 binding sites are present in the mesenchyme
surrounding major blood vessels and developing bone and in lung. These
sites provide a substrate for the collapsin-1-dependent patterning of
non-neuronal tissues perturbed in sema III (
/
) mice.
The staining patterns for mouse semaphorin D/III and chick collapsin-1
fusion proteins are indistinguishable from one another but quite
separate from that for semaphorin B and M-semaphorin F fusion proteins.
These data imply that a family of high-affinity semaphorin binding
sites similar in complexity to the semaphorin ligand family exists.
Key words:
collapsin;
semaphorin;
growth cone collapse;
dorsal root
ganglion;
sympathetic neuron;
alkaline phosphatase