ISL LIM Homeobox Protein 2 (ISL2)

By searching a sequence database for homologs of Mexican salamander (axolotl) Isl2, Showalter et al. (2004) identified human ISL2. Human and axolotl ISL2 share 84% amino acid identity. The predicted ISL2 protein contains 2 N-terminal LIM domains, followed by a homeodomain and a serine/glutamine/threonine-rich C terminus. Axolotl Isl2 localized to the nucleus in transfected human embryonic kidney cells. Tsuchida et al. (1994) found that the combinatorial expression of 4 LIM genes, Isl1, Isl2, Lim1 (LHX1), and Lim3 (LHX3), in the developing embryonic chicken defined subclasses of motor neurons that segregated into columns in the spinal cord and selected distinct axonal pathways. These genes were expressed prior to the formation of distinct motor axon pathways and before motor columns appeared.