title: Neurotrophins regulate sequential changes in neurotrophin receptor expression by sympathetic neuroblasts.
abstract: We have examined the mechanisms controlling the induction of the two NGF receptors, trkA and p75, in proliferating neuroblasts immuno-isolated from thoracolumbar embryonic sympathetic ganglia. Contrary to prior studies, we find that induction of p75 follows rather than precedes that of trkA; this late induction is consistent with the fact that p75 functions at relatively late stages of sympathetic development. trkA induction is apparently not controlled by a cell-intrinsic mechanism. Rather, this receptor is induced by environmental signals including NT-3, which also acts as an interim survival factor for these neuroblasts. trkA induction by NT-3 is consequent to its promotion of mitotic arrest, as anti-mitotic drugs also efficiently induce trkA. p75 expression is induced in trkA-expressing cells by NGF. Thus, the development of sympathetic neurons involves sequential actions of different neurotrophins, which also regulate the expression of their own and each other's receptors.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena 91125.
authors.forename: J M
authors.initials: JM
authors.lastname: Verdi
authors.forename: D J
authors.initials: DJ
authors.lastname: Anderson
mesh_terms: D000818:Animals; D002469:Cell Separation; D002470:Cell Survival / Q000187:drug effects; D005728:Ganglia, Sympathetic / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental; D006133:Growth Substances / Q000494:pharmacology; D066298:In Vitro Techniques; D008938:Mitosis; D009414:Nerve Growth Factors / Q000494:pharmacology*; D020933:Neurotrophin 3; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D020917:Receptor, trkA / Q000235:genetics*; D017475:Receptors, Nerve Growth Factor / Q000235:genetics*
chemical_list: D006133:Growth Substances; D009414:Nerve Growth Factors; D020933:Neurotrophin 3; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D017475:Receptors, Nerve Growth Factor; D020917:Receptor, trkA