The Coprinopsis cinerea Tup1 homologue Cag1 is required for gill formation during fruiting body morphogenesis.

The pileus (cap) of the fruiting body in homobasidiomycete fungi bears the hymenium, a layer of cells that includes the basidia where nuclear fusion, meiosis and sporulation occur. Coprinopsis cinerea is a model system for studying fruiting body development. The hymenium of C.