PRDM1 (PR domain containing 1) is a transcriptional repressor that affects the expression of numerous genes involved in cell proliferation, differentiation and metabolism. However, the molecular mechanisms underlying PRDM1-regulated gene expression in the DF-1 cell line remain to be elucidated. In this study, we explored the role of PRDM1 in cell proliferation and cell cycle by forced expression of PRDM1 in DF-1 cells. Our results showed an absence of endogenous PRDM1 in this cell line, while exogenous PRDM1 was specifically localized to the nucleus. Ectopic expression of PRDM1 inhibited DF-1 cell proliferation and altered clonal morphology. Furthermore, PRDM1 overexpression caused an increase in the G0/G1 phase population. The levels of p53 mRNA and the p53-regulated p21(WAF1) and MDM2 genes were significantly increased in DF-1 cells transfected with the PRDM1 expression vector. Examination of the Rb pathway further revealed that Rb, E2F-1 and p15(INK4b) alternate reading frame (ARF) mRNA were also significantly increased after transient transfection. Interestingly, the mRNA expression levels of multiple chicken cyclin genes were also increased. These results show that PRDM1 overexpression induced G0/G1 arrest in DF-1 cells through multiple parallel mechanisms, including the p53 and Rb pathways.
Keywords: Cell cycle; DF-1 cells; G0/G1 phase; PRDM1; Rb; p53.
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