Induction of neurite outgrowth by v-src mimics critical aspects of nerve growth factor-induced differentiation.
PC12 cells treated with nerve growth factor (NGF) or infected with Rous sarcoma virus differentiate into sympathetic, neuronlike cells. To compare the differentiation programs induced by NGF and v-src, we have established a PC12 cell line expressing a temperature-sensitive v-src protein. The v-src-expressing PC12 cell line was shown to elaborate neuritic processes in a temperature-inducible manner, indicating that the differentiation process was dependent on the activity of the v-src protein. Further characterization of this cell line, in comparison with NGF-treated PC12 cells, indicated that the events associated with neurite outgrowth induced by these two agents shared features but could be distinguished by others. Both NGF- and v-src-induced neurite outgrowths were reversible. In addition, NGF and v-src could prime PC12 cells for NGF-induced neurite outgrowth, and representative early and late NGF-responsive genes were also induced by v-src. However, unlike NGF-induced neurite growth, v-src-induced neurite outgrowth was not blocked at high cell density. A comparison of phosphotyrosine containing-protein profiles showed that v-src and NGF each increase tyrosine phosphorylation of multiple cellular proteins. There was overlap in substrates; however, both NGF-specific and v-src-specific tyrosine phosphorylations were observed. One protein which was found to be phosphorylated in both the NGF- and v-src-induced PC12 cells was phospholipase C-gamma 1. Taken together, these results suggest that v-src's ability to function as an inducing agent may be a consequence of its ability to mimic critical aspects of the NGF differentiation program and raise the possibility that Src-like tyrosine kinases are involved in mediating some of the events triggered by NGF.
Thomas
S M
SM
Howard Hughes Medical Institute, Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia 19104.
Hayes
M
M
D'Arcangelo
G
G
Armstrong
R C
RC
Meyer
B E
BE
Zilberstein
A
A
Brugge
J S
JS
Halegoua
S
S
D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D005786:Gene Expression Regulation; D016391:Genes, src; D007700:Kinetics; D009154:Mutation; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects; D010766:Phosphorylation; D013696:Temperature; D014443:Tyrosine / Q000378:metabolism
D009414:Nerve Growth Factors; D014443:Tyrosine