Studies on the role of cell division during neuronal differentiation in P19 EC cells

Abstract

Cell cycle progression must be tightly coordinated with cell fate choice. In this regard, cell division is one of the crucial factors that ensure differentiation process, as exemplified by mitotic clonal expansion during adipogenesis. However, there is not much of evidence and underlying mechanism that help us understand how cell division might play a role in other types of differentiation, ensuring controlled tissue development and homeostasis. Here, I focused on the involvement of cell division during neuronal differentiation. I used retinoic acid (RA)-induced in vitro neurogenesis system of P19 embryonic carcinoma cells to examine the direct link between cell division and neuronal differentiation. I observed that cell cycle blockers inhibited neuronal differentiation of P19 cells. In order to investigate the underlying mechanisms, I screened for RA target genes whose transcripts were reduced with cell cycle blockers and identified Tshz1 as a candidate for the cell division-dependent genes. The promoter analysis of Tshz1 found the minimal essential region for RA and cell division-dependent transcriptional activation. Through computational sequence analysis of the promoter, E2F1 was predicted a possible upstream transcription factor for Tshz1. Furthermore, the E2F1 binding activity on the Tshz1 promoter was reduced with the thymidine treatment. Taken together, E2F1 may function as a transcription factor whose activity is controlled in a cell division-specific manner for RA induction of Tshz1 expression. This study is an example that cell division itself functions as a regulatory mechanism to ensure neuronal differentiation.