We previously identified a novel non-coding immediate early gene, termed kakusei , from the honeybee (Apis mellifera) and used it as a marker to detect neural activity in the brains of foraging workers (Kiya et al .,2007). Here, we investigated the detailed kakusei gene structure. Expression analysis revealed that, in addition to the neural activity-inducible transcript variant, multiple neural activity-independent transcript variants were constitutively expressed from the same kakusei locus. In situ hybridization revealed that constitutive-type kakusei variants were detected in the whole brain and the RNA was localized predominantly in the neural nuclei, like the inducible-type variant, suggesting the concerted action of inducible- and constitutive-types of kakusei transcript variants on nuclear function.