The sub-cellular distribution of β-catenin in the neural differentiation of ra induced P19 EC cells

Wnt signals have been shown to play an important role in the development of the central nervous system (CNS) of mouse. In our previous work, it was demonstrated that Wnt signal could initiate differentiation of P19 EC cells. In the present investigation, it was examined with RT-PCR whether expression of β-catenin, a downstream gene of Wnt in its signal transduction pathway, is regulated. It was found that the level of protein or transcript β-catenin during P19 neuronal differentiation was not changed. However, immunostaining data showed that β-catenin was translocalized into nuclei after retinoic acid induced P19 cell aggregates were trypsinized and cultured in serum free N₂ medium for 2 and 4 d. In this period, transcription of En-2, a downstream target gene of Wnt signal, increased evidently. The above data suggest that Wnt signals are involved in the early stage of neuronal differentiation process of P19 cell. Meanwhile, the distribution of β-catenin on the neurites indicates that this protein may also be involved in neuritis outgrowth process.