develops from expresses elav external sensory organ precursor cell external sensory organ precursor cell pNb antennal olfactory receptor neuron precursor Nba 2019-12-12T12:01:21Z FBbt:00048525 Terminal daughter cell of an external sensory organ precursor cell pNb in the developing antenna. It may undergo apoptosis or differentiate into an olfactory receptor neuron, depending upon which sensillum it is in. It can be distinguished from the Nbb precursor based on its expression of embryonic lethal abnormal vision (elav). fly_anatomy.ontology