ATF5 deficiency causes abnormal cortical development.

Activating transcription factor 5 (ATF5) is a member of the cAMP response element binding protein (CREB)/ATF family of basic leucine zipper transcription factors. We previously reported that ATF5-deficient (ATF5) mice exhibited behavioural abnormalities, including abnormal social interactions, reduced behavioural flexibility, increased anxiety-like behaviours, and hyperactivity in novel environments. ATF5 mice may therefore be a useful animal model for psychiatric disorders. ATF5 is highly expressed in the ventricular zone and subventricular zone during cortical development, but its physiological role in higher-order brain structures remains unknown. To investigate the cause of abnormal behaviours exhibited by ATF5 mice, we analysed the embryonic cerebral cortex of ATF5 mice. The ATF5 embryonic cerebral cortex was slightly thinner and had reduced numbers of radial glial cells and neural progenitor cells, compared to a wild-type cerebral cortex. ATF5 deficiency also affected the basal processes of radial glial cells, which serve as a scaffold for radial migration during cortical development. Further, the radial migration of cortical upper layer neurons was impaired in ATF5 mice. These results suggest that ATF5 deficiency affects cortical development and radial migration, which may partly contribute to the observed abnormal behaviours.