Actomyosin cable formation is the dorsal-most epidermal cells is abolished when edΔC.Scer\UAS.T:Avic\GFP is expressed via Scer\GAL4c381 in the adjacent peripheral amnioserosa cells. These embryos exhibit little or no defect in in the elongation of the more ventral rows of epidermal cells.
The dorsal-most epidermal cells expressing edΔC.Scer\UAS.T:Avic\GFP via Scer\GAL4prd.RG1 adopt a fan shape with their leading edge splayed wide along the anterior-posterior (AP) axis compared with the narrow leading edge of the wild-type cells. These cells also appear to acquire a migration advantage compared with wild-type cells and they extend further dorsally than their neighbours. In later stages, they establish premature contacts at the dorsal midline.