A screen for tendon-specific genes uncovers new and old components involved in muscle-tendon interaction.

The formation of complex tissues requires the assembly of distinct cell types that often migrate over long distances in order to interact with each other and establish a functional tissue. The establishment of the contractile tissue in the Drosophila embryo has been used as a model system in which to study how the interplay between distinct cell types results in a complex, functioning tissue. The Drosophila contractile tissue is composed of multi-nucleated muscle cells that are attached to individual specialized ectodermal cells, named tendon cells, at each end. The tendon cells are anchored to the cuticle external skeleton on their apical side and form integrin-dependent myotendinous junctions at their basal end. In order for the complex muscle-pattern to form, muscles must undergo several tightly regulated processes: They need to migrate towards their respective tendon cells, arrest migration upon arrival to the tendon cells and form integrin-mediated muscle-tendon junctions (MTJs) in an accurate manner that would guarantee appropriate muscle function.(1,2) The regulation of many of these events is still poorly understood, driving us to search for novel mechanisms that enable the functionality of the contractile tissue.