Neurite outgrowth in response to transfected N-CAM and N-cadherin reveals fundamental differences in neuronal responsiveness to CAMs.
Different neuronal populations were used to compare the neurite outgrowth-promoting activities of N-CAM and N-cadherin expressed via gene transfer on the surface of nonneuronal cells. In contrast to a previously reported developmental loss of retinal ganglion cell responsiveness to N-CAM, these cells exhibited an increased and maintained responsiveness to N-cadherin over the same developmental period (E6-E11). N-CAM and N-cadherin responses could be specifically inhibited by their own antibodies, but not by antisera to the beta 1 integrin family or the L1/G4 glycoprotein. Cerebellar neurons showed qualitative differences in the nature of the dose-response curves for transfected N-CAM expression (highly cooperative) versus N-cadherin expression (linear). In addition "subthreshold" levels of N-CAM expression, which do not normally support neurite outgrowth, did so when coexpressed with functional levels of N-cadherin. These studies show fundamental differences in neuronal responsiveness to cell adhesion molecules and suggest a more dynamic regulation for N-CAM-dependent neurite outgrowth than for N-cadherin-dependent outgrowth.
Doherty
P
P
Department of Experimental Pathology UMDS, Guy's Hospital, London Bridge, England.
Rowett
L H
LH
Moore
S E
SE
Mann
D A
DA
Walsh
F S
FS
D000818:Animals; D000906:Antibodies / Q000502:physiology; D001369:Axons / Q000502:physiology*; D015820:Cadherins / Q000235:genetics / Q000502:physiology*; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D002642:Chick Embryo; D004056:Differential Threshold; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005314:Embryonic and Fetal Development; D009474:Neurons / Q000502:physiology*; D010455:Peptides / Q000494:pharmacology; D012165:Retinal Ganglion Cells / Q000502:physiology; D014162:Transfection
D000906:Antibodies; D015820:Cadherins; D015816:Cell Adhesion Molecules, Neuronal; D010455:Peptides