Highly deregulated expression of AHI-1 in human leukemic cell lines. (A) The panel shows absolute AHI-1 transcript levels calculated as described in “Patients, materials, and methods” from real-time RT-PCR analyses of RNA isolated from 16 human leukemic cell lines. Data for total normal human BM cells (data from Figure 2) are shown for comparison. Values shown are the mean ± SEM of data from 3 independent RNA isolates from each cell line. The horizontal dotted line indicates the highest increases in AHI-1 transcript levels found in 5 human cell lines. Below is a schematic diagram of the full-length human AHI-1 isoform I with arrows indicating the position of the specific primers at the 5′ end of the gene used to amplify all transcript isoforms concomitantly (see also Figure 4A). *Stop codons. (B) Detection of different species of AHI-1 transcripts by Northern blot analysis of total RNA from the cell lines analyzed in panel A. Lanes were loaded with 20 μg of total RNA and the blots were probed using a 1.4-kb AHI-1 cDNA fragment.