NEURONAL DIFFERENTIATION OF P19 EMBRYONAL CELLS EXHIBITS CELL-SPECIFIC REGULATION OF NEUROTROPHIN RECEPTORS

DURING development, the regulation of expression of the Trk family of tyrosine kinase receptors plays an important role in defining the cell ular responses to neurotrophin action. We report here that neurotrophi n receptors are differentially expressed in distinct populations of re tinoic acid-differentiated P19 cells. TrkB, the tyrosine kinase recept or for brain-derived neurotrophic factor, and LNGFR, the low-affinity receptor for all neutrophins, are preferentially expressed in P19-deri ved neurones. In contrast, retinoic acid induces the expression of Trk A, the high-affinity receptor for nerve growth factor, and of a non-ca talytic form of TrkB, in non-neural subsets of differentiated cells. W e propose P19 cells as a model system to study the mechanisms controll ing the expression of neurotrophin receptors and the responsiveness of developing neurones to a specific neurotrophin.