TAL-1, also known as SCL (stem cell leukemia), is a serine phosphoprotein and basic-helix-loop-helix transcription factor. TAL-1 is implicated in the genesis of hemopoietic malignancies and is a positive regulator of erythroid differentiation. A nonrandom, site-specific TAL-1 chromosomal translocation is commonly associated with oncogenic transformation in many T-cell acute lymphoblastic leukemias. TAL-1 binds to the LIM domain containing protein Rhombotin 2 (RBTN2), where it forms a complex with GATA1 or GATA 2 that is essential for erythropoiesis.