HBP1 also regulates Pim-1 expression.
A, schematic diagram of the Pim-1 promoter. Shown is the HBP1 affinity site within the Pim-1 promoter at positions bp −1423 to −1451 from the transcriptional start site (Luc-Pim-1; top). Luc-ΔPim-1 is a mutant Pim-1 promoter with a deletion in the HBP1 affinity site (bottom). B, exogenous HBP1 regulates Pim-1 expression. The protein levels of HBP1 and Pim-1 were measured by immunoblotting in HeLa, U2OS, or 2BS cells transfected with vector (as control) or HBP1 expression plasmid (left). The mRNA levels of HBP1 and Pim-1 were measured by real-time PCR in HeLa, U2OS, or 2BS cells transfected with vector (as control) or HBP1 expression plasmid (right). Error bars represent S.D. *, p < 0.05; **, p < 0.01. C, endogenous HBP1 regulates Pim-1 expression. The protein levels of HBP1 and Pim-1 were measured by immunoblotting in HeLa, U2OS, or 2BS cells transfected with pLL3.7 (as a control) or pLL3.7-shHBP1 (left). The mRNA levels of HBP1 and Pim-1 were measured by real-time PCR in HeLa, U2OS, or 2BS cells transfected with pLL3.7 (as a control) or pLL3.7-shHBP1(right). Error bars represent S.D. *, p < 0.05; **, p < 0.01.