Hindgut visceral mesoderm requires an ectodermal template for normal development in Drosophila

During Drosophila embryogenesis, the development of the midgut endoderm dep ends on interactions with the overlying visceral mesoderm, Here we show tha t the development of the hindgut also depends on cellular interactions, in this case between the inner ectoderm and outer visceral mesoderm, In this s ection of the gut, the ectoderm is essential for the proper specification a nd differentiation of the mesoderm, whereas the mesoderm is not required fo r the normal development of the ectoderm, Wingless and the fibroblast growth factor receptor Heartless act over seque ntial but interdependent phases of hindgut visceral mesoderm development. W ingless is required to establish the primordium and to enhance Heartless ex pression. Later, Heartless is required to promote the proper differentiatio n of the hindgut visceral mesoderm itself.