Transcriptional activator involved in the development of insulin-producting beta cells in the endocrine pancreas (By similarity). May also be involved in specifying diencephalic neuromeric boundaries, and in controlling the expression of genes that play a role in axonal guidance. Binds to elements within the NEUROD1 promoter (By similarity). Interacts with OLIG2. The homeodomain is essential for interaction with OLIG2. Belongs to the NK-2 homeobox family.