The Drosophila wing originates as an imaginal disc, which is divided into anterior and posterior domains separated by a straight antero-posterior (AP) boundary. This barrier is characterised by an actomyosin cable and increased mechanical tension at cell junctions, termed cell bond tension. Engrailed and Invected, expressed in the posterior compartment, maintain the straight morphology of the AP boundary both through the induction of the morphogen Hedgehog (Hh) and via an Hh-independent mechanism. How do such signalling pathways regulate cell bond tension at the AP boundary? In this study (p. 3845), Christian Dahmann and co-workers show that the difference in Hh activity between the two compartments drives the local increase in cell bond tension along the AP boundary and is required to bias cell intercalations to maintain its straight shape. Furthermore, increased mechanical tension is generated autonomously at the boundary and does not depend on the actomyosin cable or the Hh-independent mechanism that contributes to the preservation of the AP boundary shape. By linking the molecular players and mechanical determinants, this study sheds light on the mechanisms governing the physical separation of adjacent cell populations destined to different cell fates.
- © 2015. Published by The Company of Biologists Ltd