Genomic and physiological mechanisms underlying skin plasticity during water to air transition in an amphibious fish

Dong Y, Blanchard TS, Noll A, Vasques P, Schmitz J, Kelly SP, Wright PA, Whitehead A

Abstract

The terrestrial radiation of vertebrates required changes in skin thatresolved the dual demands of maintaining a mechanical andphysiological barrier while also facilitating ion and gas transport.Using the amphibious killifish Kryptolebias marmoratus, we foundthat transcriptional regulation of skin morphogenesis was quicklyactivated upon air exposure (1 h). Rapid regulation of cell–celladhesion complexes and pathways that regulate stratum corneumformation was consistent with barrier function and mechanicalreinforcement. Unique blood vessel architecture and regulation ofangiogenesis likely supported cutaneous respiration. Differences inionoregulatory transcripts and ionocyte morphology were correlatedwith differences in salinity acclimation and resilience to air exposure.Evolutionary analyses reinforced the adaptive importance of thesemechanisms. We conclude that rapid plasticity of barrier, respiratoryand ionoregulatory functions in skin evolved to support theamphibious lifestyle of K. marmoratus; similar processes may havefacilitated the terrestrial radiation of other contemporary and ancientfishes.