Transcription factor involved in early neurogenesis; sensillum basiconica formation and maybe sensillum trichodea development. Promotes multiple dendritic (MD) neuron formation. Required for olfactory sensilla; regulated by lozenge (lz). Efficient DNA binding requires dimerization with another bHLH protein. Interacts with Daughterless (da). During embryonic development, expression is seen in a small cluster of ectodermal cells during stage 10 which becomes restricted to 1 cell by stage 11. Expression is lost from this cell in the thorax and then the abdomen. Later expression is restricted to sensory organ precursors. Very transient expression was detected in distal leg disks at approximately 0-4 hours after puparium formation (APF), correlating with the anlage of the innervated tarsal claw.