Conditional inactivation of <i>Hhex</i> prolongs latency of <i>Lmo2</i>-induced T-ALL.

<p>(<b>A</b>) Genomic DNAs from bone marrow (lanes 2, 5), spleen (3, 6), and thymus (lanes 4, 7) were analyzed using primers specific for floxed <i>Hhex</i> or deleted <i>Hhex</i> (<i>cKO</i>); lane 1 is H₂O; bands are indicated by blue arrows. Tissues from two representative mice are shown: <i>Hhex^lox/lox</i> and <i>Hhex^lox/lox; Vav-iCre</i> (designated <i>Hhex cKO</i>). (<b>B</b>) Single cell suspension was prepared from <i>Hhex^lox/lox</i> or <i>Hhex cKO</i> thymi and analyzed by flow cytometry for CD4 (x-axis) and CD8 (y-axis) antigen expression. Numbers show the percentage of cells in each quadrant. (<b>C</b>) Graph shows survival analysis of <i>Lmo2/Hhex cKO</i> and <i>Lmo2/Hhex^lox/lox</i> mice (n = 16 per group). The median survival of <i>Lmo2/Hhex^lox/lox</i> mice was 306 days whereas for <i>Lmo2/Hhex cKO</i>, the median was not yet attained. <i>P</i> value represents the comparison of survival times by Log-rank test. (<b>D</b>) Genomic DNA was prepared from thymi involved with T-ALL of <i>Lmo2/Hhex^lox/lox</i> (n = 3, lanes 2–4) and <i>Lmo2/Hhex cKO</i> mice (n = 2, lanes 5, 6); lane 7 shows positive controls for PCR of deleted (cKO) and floxed <i>Hhex</i> (blue arrows).