Jk. Nyhus et Jl. Denburg, THE IN-VIVO REGULATION OF PIONEER AXON GROWTH BY FGF-2 AND HEPARAN-SULFATE PROTEOGLYCANS IN CULTURED EMBRYOS OF THE COCKROACH, Molecular and cellular neurosciences (Print), 11(5-6), 1998, pp. 305-323
Antibody perturbation experiments on cultured cockroach embryos demons
trated that a localized source of an FGF-2-like immunoreactive molecul
e in the head is required for the proper growth of pioneer axons in th
e leg. The study of axon growth in various fragments of cultured embry
os and in the presence of various conditioned media showed that FGF-P
is needed to counteract the effects of an inhibitor of axon growth pro
duced in the body trunk of the embryo. Endogenous heparan sulfate prot
eoglycans mediate these effects of FGF-2 on axon growth. The results o
f experiments with FGF-2 and/or body trunk axon growth inhibitor added
to the culture medium indicate that more globally and uniformly distr
ibuted molecules may play as important a role in axon guidance as the
more spatially restricted guidance cues. The results are interpreted i
n terms of a model that is consistent with a role for the FGF-2 recept
or in axon growth.