The Role of the dpp-Group Genes in Dorsoventral Patterning of the Drosophila Embryo

Publisher Summary This chapter discusses the role of the dpp -group genes in dorsoventral (DV) patterning of the drosophila embryo. The DV pattern of the Drosophila embryo can be subdivided into four major regions, the anlagen of which can be traced back to the cellular blastoderm stage. The chapter investigates such a transition from a maternally generated morphogen gradient to a zygotic gradient that controls more pattern refinement. In Drosophila , the DV pattern depends on a single, maternally generated gradient, the nuclear concentration gradient of the dorsal ( dl ) gene product. This gradient has peak levels ventrally and it directly organizes the pattern on the ventral side of the embryo. However, the patterning of the dorsal half of the embryo, though also dependent on the dl protein gradient, occurs more indirectly by the formation of the dpp morphogen gradient with the highest activity levels in the dorsalmost regions. The differences between patterning on the ventral and the dorsal sides of the Drosophila embryo, then the genes involved in the formation and interpretation of the dpp activity gradient are also described in the chapter.