This entry includes highly related proteins with a Myc-type, basic helix-loop-helix (bHLH) domain, including T-cell acute lymphocytic leukemia proteins 1 and 2 (TAL1 and TAL2), helix-loop-helix proteins 1 and 2 (NHLH1/HEN1 and NHLH2/HEN2), and protein lyl-1 (LYL1). The bHLH domain is required for protein dimerization and DNA binding []. TAL1 may be a positive regulator of erythroid differentiation []. The TAL1 and TAL2 genes are altered in T-cell acute lymphoblastic leukemia []. The NHLH1 and NHLH2 genes are expressed in the developing nervous system, especially cell lines derived from neuroblastoma, PNET, and small cell lung cancer [], and the proteins may have regulatory functions in the developing nervous system []. LYL1 has a role in primitive erythropoiesis []. A chromosomal aberration involving the LYL1 gene may be a cause of a form of T-cell acute lymphoblastic leukemia [].
