Prospero is a large drosophila transcription factor protein that is expressed in all neural lineages of drosophila embryos. It is needed for correct expression of several neural proteins and in determining the cell fates of neural stem cells. homologs of prospero are found in a wide range of animals including humans with the highest level of similarity being found in the C-terminal 160 amino acids. This region was identified as containing an atypical homeobox domain followed by a prospero domain. However, the structure shows that these two regions form a single stable structural domain as defined here. This homeo-prospero domain binds to DNA.