title: Otx2 expression and implications for olfactory imprinting in the anemonefish, Amphiprion percula.
abstract: The otx2 gene encodes a transcription factor (OTX2) essential in the formation of the brain and sensory systems. Specifically, OTX2-positive cells are associated with axons in the olfactory system of mice and otx2 is upregulated in odour-exposed zebrafish, indicating a possible role in olfactory imprinting. In this study, otx2 was used as a candidate gene to investigate the molecular mechanisms of olfactory imprinting to settlement cues in the coral reef anemonefish, Amphiprion percula. The A. percula otx2 (Ap-otx2) gene was elucidated, validated, and its expression tested in settlement-stage A. percula by exposing them to behaviourally relevant olfactory settlement cues in the first 24 hours post-hatching, or daily throughout the larval phase. In-situ hybridisation revealed expression of Ap-otx2 throughout the olfactory epithelium with increased transcript staining in odour-exposed settlement-stage larval fish compared to no-odour controls, in all scenarios. This suggests that Ap-otx2 may be involved in olfactory imprinting to behaviourally relevant settlement odours in A. percula.
authors.affiliation: School of Marine and Tropical Biology, James Cook University , Townsville QLD 4811 , Australia ; Centre for Tropical Fisheries and Aquaculture, James Cook University , Townsville QLD 4811 , Australia.
authors.forename: Heather D
authors.initials: HD
authors.lastname: Veilleux
authors.forename: Lynne
authors.initials: L
authors.lastname: Van Herwerden
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Cole
authors.forename: Emily K
authors.initials: EK
authors.lastname: Don
authors.forename: Christian
authors.initials: C
authors.lastname: De Santis
authors.forename: Danielle L
authors.initials: DL
authors.lastname: Dixson
authors.forename: Amelia S
authors.initials: AS
authors.lastname: Wenger
authors.forename: Philip L
authors.initials: PL
authors.lastname: Munday
keywords: Candidate gene; Coral reef fish; Habitat selection; In-situ hybridisation; Memory; Olfaction