Controls the genesis of the spleen. Binds to the DNA sequence 5'-GGCGGTAAGTGG-3'. Interacts with MEIS1, MEIS2, PBX1, PBX2 and PBX3. A chromosomal aberration involving TLX1 may be a cause of a form of T-cell acute lymphoblastic leukemia (T-ALL). Translocation t(10;14)(q24;q11) with TCRD. TLX1 is oriented in a head-to-head manner with TDI. Both genes share the same promoter with robust bidirectional activity.