TAL1 knockdown reveals regulation of promoters identified by ChIP on chip. Quantitative RT-PCR on RNA prepared from 4 Jurkat-cell clones stably expressing a control shRNA (□) or the TAL1 shRNA (▪) reveals that 3 of the TAL1 target genes are significantly down-regulated by TAL1 knockdown (TRAF3, RAB40B, and EPHB1; top) and 3 are up-regulated (PTPRU, TTC3, and RPS3A; bottom), reflecting genes that would be activated and repressed by TAL1, respectively. Error bars represent standard deviations of triplicate measurements (quantification replicas) normalized to GAPDH levels. The results shown are displayed as a percentage of the mean levels of the control samples. Error bars indicate standard deviations.