Behavioral phenotyping of Zip8 393T-KI mice for in vivo study of schizophrenia pathogenesis

Genetic studies have informed on the genetic landscape of schizophrenia, and the next challenge is to link the genetic associations to mechanistic studies. A common single nucleotide polymorphism in the zinc and manganese transporter ZIP8 (rs13107325; ZIP8 A391T) is a top candidate to prioritize for functional studies because it is a missense mutation that results in hypomorphic protein function. With this goal, we have established a mouse model (Zip8 393T-knock-in (KI)), and here, we report the results of brain necropsy and initial behavioral phenotyping experiments in the KI mice using open field testing, elevated plus maze, Y-maze, and trace fear conditioning. Overall, male, homozygous KI mice may exhibit subtle defects in cognition and spatial learning, otherwise the baseline testing supports minimal behavioral differences between wild-type and Zip8 393T-KI mice. There were no genotype-specific alterations of gross or microscopic neuroanatomy. These experiments are important to establish the baseline characteristics of the Zip8 393T-KI mice that may be perturbed in animal models of schizophrenia and position the Zip8 393T-KI mouse as an important model for translational studies of schizophrenia pathogenesis.