Structural and functional divergence of two fish aquaporin-1 water channels following teleost-specific gene duplication

Abstract
Teleost radiation in the oceans required specific physiological adaptations in eggs and early embryos to survive in the hyper-osmotic seawater. Investigating the evolution of aquaporins (AQPs) in these vertebrates should help to elucidate how mechanisms for water homeostasis evolved. The marine teleost gilthead sea bream (Sparus aurata) has a mammalian aquaporin-1 (AQP1)-related channel, termed AQP1o, with a specialized physiological role in mediating egg hydration. However, teleosts have an additional AQP isoform structurally more similar to AQP1, though its relationship with AQP1o is unclear.