Based on studies in mice, the transcription factor ISL1, in complex with either LHX3 or LHX4, binds to an evolutionarily conserved LIM-HD binding site in the enhancer of the SLIT2 gene, located in the sixth intron of the SLIT2 gene. The complex of ISL1 and LHX4 regulates SLIT2 expression in branchiomotor neurons, while the complex of ISL1 and LHX3 regulates SLIT2 expression in somatic motor neurons (Kim et al. 2016). From the previous structural studies of the ISL1 complex with LHX3, conducted using mouse and rat proteins, it is known that LDB1 is also part of this complex (Thaler et al. 2002).