Expression of Bcl2-A1 is regulated by Spi-B. (A) CAL-1 cells were transduced with vectors expressing Spi-B cDNA, Spi-B shRNAs or appropriate control vectors and sorted for GFP expression after 48 hours. Bcl2-A1 mRNA expression levels were measured by qPCR in 3 independent experiments. Values are normalized to control transduced cells (*P < .05; **P < .01). (B-C) Short term induction of Spi-B using Spi-B∼ER transduced cells incubated with (black bar) or without (white bar) 4HT after pretreatment with cycloheximide to avoid de novo protein synthesis. Bcl2-A1 (B) and CD40 (C) mRNA expression levels were measured by qPCR. Values were normalized to control transduced cells incubated without 4HT. (D) mRNA levels of antiapoptotic genes of the Bcl2 family were measured by QPCR in Spi-B∼ER–transduced CAL-1 cells after 4 hours of incubation in the presence (black bars) or absence (white bars) of 4HT. Values were normalized to transduced cells incubated without 4HT.