Balancing Act: Investigating the Coordinated Mechanics of Germband and Amnioserosa in Drosophila Morphogenesis

Despite being a short-lived, extraembryonic tissue, the amnioserosa plays critical roles in the major morphogenetic events of Drosophila embryogenesis. These roles involve both cellular mechanics and biochemical signaling. Its best-known role is in dorsal closure – well-studied by both developmental biologists and biophysicists – but the amnioserosa is also important during earlier developmental stages. Here, we provide an overview of amnioserosa specification and its role in several key developmental stages: germband extension, germband retraction, and dorsal closure. We also compare embryonic development in Drosophila and its relative Megaselia to highlight how the amnioserosa and its roles have evolved. Placed in context, the amnioserosa provides a fascinating example of how signaling, mechanics and morphogen patterns govern cell-type specification and subsequent morphogenetic changes in cell shape, orientation, and movement