LMO2 gene expression in t(17;19)-ALL. (A) Schematic representation of 2 LMO2 gene promoters and primers for real-time RT-PCR analysis. Primers directed toward exons 1 and 2 specifically detect transcripts derived from the distal promoter, and those directed toward exons 4 and 5 detect transcripts derived from both the distal and proximal promoters. (B) Relative LMO2 gene expression determined by real-time RT-PCR using the primers for exons 4 and 5. Arrow indicates T-ALL cell line with t(11;14), and asterisk indicates the level of LMO2 transcripts in a primary leukemia sample from the patient with t(17;19)-ALL. The P value determined by Mann-Whitney test is indicated. (C) Relative LMO2 gene expression determined by real-time RT-PCR using the primers for exons 1 and 2. (D) Correlation between the levels of LMO2 transcripts quantified by the primers for exons 4 and 5 (vertical axis) and those for exons 1 and 2 (horizontal axis). (E) LMO2 gene expression in CD34⁺/CD19⁻, CD34⁺/CD19⁺, CD19⁺/IgM⁻, and CD19⁺/IgM⁺ populations of cord blood mononuclear cells (MNCs) and CD19⁺ population of peripheral blood MNCs. Relative LMO2 gene expression was determined by real-time RT-PCR using UOC-B1 as a control with the primers for exons 1 and 2 and the primers for exons 4 and 5. The gene expression level of β-actin was used as an internal control. SE of triplicated samples was always less than 10%. (F) Ratio of LMO2 gene expression derived from the distal promoter to total LMO2 gene expression in ALL cell lines. LMO2 gene expression in the cell lines that expressed a total LMO2 gene level of at least 10 times lower than that in UOC-B1 was semiquantifiedby real-time PCR with the specific primers for LMO2 transcripts sourced at the distal promoter and for total LMO2 transcripts. The dark areas indicate a proximal promoter-predominant pattern (ratio < 0.25) or a distal promoter-predominant pattern (ratio > 0.75).