Expression of the EPS-ISC transgene is B cell specific and induced by stimuli. (A) RT-PCR was performed with RNA extracted from enriched wild-type B cells (lanes 1-4), EPS21 (lanes 5-8), or EPS11 (lanes 9-12) transgenic mice after 2 days of culture in the presence of indicated stimuli. In samples, which were amplified with Iϵ and CH1 primers, the top band corresponds to the transgenic transcript (T), and the bottom band to the endogenous (E) GL ϵ transcript. Only the transgenic band is detected in the Iϵ-tag PCR. The Mb-1 RT-PCR was used for cDNA quality control. (B) RNA expression from the same experiment was quantified by real-time RT-PCR. All samples were compared with the noninduced EPS21 sample. The y axis shows relative expression. Mean values and SD of triplicates are shown. (C) RT-PCR was performed with RNA extracted from different organs of an EPS21 transgenic mouse. The γ-actin transcript was used to control for cDNA quality.