RT Journal Article SR Electronic T1 oskar acts with the transcription factor Creb to regulate long-term memory in crickets JF bioRxiv FD Cold Spring Harbor Laboratory SP 2022.10.24.513429 DO 10.1101/2022.10.24.513429 A1 Arpita Kulkarni A1 Ben Ewen-Campen A1 Kanta Terao A1 Yukihisa Matsumoto A1 Yaolong Li A1 Takayuki Watanabe A1 Jonchee A. Kao A1 Swapnil S. Parhad A1 Guillem Ylla A1 Makoto Mizunami A1 Cassandra G. Extavour YR 2022 UL http://biorxiv.org/content/early/2022/10/25/2022.10.24.513429.abstract AB Novel genes have the potential to drive the evolution of new biological mechanisms, or to integrate into pre-existing regulatory circuits and contribute to the regulation of older, conserved biological functions. One such gene, the novel insect-specific gene oskar, was first identified based on its role in establishing the Drosophila melanogaster germ line. We previously showed that this gene likely arose through an unusual domain transfer event involving bacterial endosymbionts, and played a somatic role before evolving its well-known germ line function. Here, we provide empirical support for this hypothesis in the form of evidence for a novel neural role for oskar. We show that oskar is expressed in the adult neural stem cells of a basally branching insect, the cricket Gryllus bimaculatus. In these stem cells, called neuroblasts, oskar is required together with the ancient animal transcription factor Creb to regulate long-term (but not short-term) olfactory memory. We provide evidence that oskar positively regulates Creb, which plays a conserved role in long-term memory across animals, and that oskar in turn may be a direct target of Creb. Together with previous reports of a role for oskar in nervous system development and function in crickets and flies, our results are consistent with the hypothesis that oskar’s original somatic role may have been in the insect nervous system. Moreover, its co-localization and functional cooperation with the conserved pluripotency gene piwi in the nervous system may have facilitated oskar’s later co-option to the germ line in higher insects.Competing Interest StatementThe authors have declared no competing interest.