Truncated C/EBPα-p30 isoform induces expression of pre-miR-181a-1. (A) K562 cells were stably transfected with β-estradiol inducible C/EBPα-p30 or p42 ER fusion constructs^31,37  enabling nuclear translocation of ectopically expressed C/EBPα proteins. For negative control, vector expressing the ER domain alone was included. Total RNA was analyzed for the expression of miR-181a-1 (black bars) and miR-181a-2 (white bars) precursors by quantitative real-time PCR. (B) Total protein lysates from K562 stable lines described in panel A were analyzed for the relative expression of C/EBPα-ER fusion proteins by Western blot stained with C/EBPα antibody. To control for loading, staining with β-tubulin antibody was used. (C) Quantitative real-time RT-PCR data and (D) Northern blot data of THP-1 cells stably expressing HA-tagged C/EBPα-p30 isoforms or empty vector.³⁵  Mature miR-181a expression was found to be highest in those THP-1 cells expressing the HA-tagged C/EBPα-p30 isoform. Northern blot shows an increase for both pre-miR-181a-1 and mature miR-181a expression for those cells expressing the HA-tagged C/EBPα-p30 (snRNA U6 was used as an internal loading control). (E) Western blot data showing the expression of HA-tagged C/EBPα-p30 and empty vector for those cells described in panels C and D. In panels A and C, average of triplicate measurements is shown and error bars denote SEM.