Gene expression profile of L428 cells conditional expressing PU.1

PU.1 is an Ets family transcription factor that is essential for the differentiation of both myeloid and lymphoid cells. PU.1 is down-regulated in classical Hodgkin lymphoma cells via methylation of the PU.1 promoter. To evaluate whether down-regulation of PU.1 is essential for the growth of cHL cells, we generated L428 derived cell lines conditionally express PU.1 by tet-off system (designated L428tetPU.1). Conditonally expressed PU.1 by tetracycline removal induced complete growth arrest and apoptosis in L428 cells. To elucidate the mechanisms underlying cell cycle arrest and apoptosis induced by PU.1, we compared gene expression profiles of L428tetPU.1 cells 0, 1 and 3 days after PU.1 induction, by DNA microarray. We extracted total RNA from L428tetPU.1 cells 0, 1 and 3 days after PU.1 induction by tetracycline removal. We compared gene expression profiles of KL428tetPU.1 cells 0, 1 and 3 days after PU.1 induction using DNA microarray analysis. 4 independent experiments were performed with each RNA samples.