Herzog is not required for mushroom body development or courtship learning & memory but is required for eye development in Drosophila melanogaster

Herzog (Hzg, CG5830) shares similarity to members of the haloacid dehalogenase subfamily of small CTD phosphatases. In Drosophila it is a maternal gene essential for establishment of embryonic segment polarity, and oligomerization is required for activation of phosphatase activity. While Hzg is expressed in the brain, its role has not been investigated. To that end, we further characterized Hzg expression in the brain and found that it is highly expressed in neurons of the mushroom body where it localises to axons, and is also expressed in cortical glia. We investigated its role in mushroom body development as well as courtship learning and memory, but found that knockdown of Hzg had no impact on these processes. In contrast, knockdown in post-mitotic neurons in the eye resulted in disruption to ommatidial patterning and pigmentation, indicating it plays an important role in eye development.