Modulates gene transcription; simultaneously generates both a specific activator and an inhibitor of gene transcription, capable of modulating two distinct regulatory programs during neural development. Has a role in olfactory behavior. Coexpressed with vvl in overlapping subsets of neurons in the embryonic central nervous system. Expressed in olfactory neurons. Belongs to the POU transcription factor family. Class-4 subfamily. Was originally thought that the I-POU homeobox is unable to bind DNA because it lacks two N-terminal basic residues. Was originally thought to interact with vvl.