Coordinated locomotion of Drosophila larvae depends on accurate patterning and stable attachment to the cuticle of both muscles and proprioceptors (chordotonal organs). Unlike muscle spindles in mammals, the fly chordotonal organs are not embedded in the body-wall muscles. Yet, the contractile system (muscles and tendons) and the chordotonal organs constitute two parts of a single functional unit that controls locomotion, and thus must be patterned in full coordination. It is not known how such coordination is achieved. Here we show that the positioning and differentiation of the migrating chordotonal organs are instructed by Stripe, the same transcription factor that promotes tendon cell specification and differentiation and is required for normal patterning of the contractile system. Our data demonstrate that although chordotonal organs are patterned in a Stripe-dependent mechanism similarly to muscles, this mechanism is independent of Stripe activity in tendon cells. Thus, the two parts of the locomotive system use similar but independent patterning mechanisms that converge to form a functional unit. Stripe plays at least a dual role in chordotonal development. It is required within the ligament cells for terminal differentiation and proper migration, without which no induction of ligament attachment cells takes place. Stripe's activity is then necessary within the recruited cells for their differentiation as attachment cells. Similarly to the biphasic differentiation program of tendons, terminal differentiation of chordotonal attachment cells is associated with sequential activation of the two Stripe isoforms-Stripe B and Stripe A.

In spite of our conceptual view of how differential gene expression is used to define different cell identities, we still do not understand how different cell identities are translated into actual cell properties. The example discussed here is that of the fly wing, which is composed of two main cell types: vein and intervein cells. These two cell types differ in many features, including their adhesive properties. One of the major differences is that intervein cells express integrins, which are required for the attachment of the two wing layers to each other, whereas vein cells are devoid of integrin expression. The major signaling pathways that divide the wing to vein and intervein domains have been characterized. However, the genetic programs that execute these two alternative differentiation programs are still very roughly drawn. Here we identify the bHLH protein Delilah (Dei) as a mediator between signaling pathways that specify intervein cell-fate and one of the most significant realizators of this fate, βPS integrin. Dei's expression is restricted to intervein territories where it acts as a potent activator of βPS integrin expression. In the absence of normal Dei activity the level of βPS integrin is reduced, leading to a failure of adhesion between the dorsal and ventral wing layers and a consequent formation of wing blisters. The effect of Dei on βPS expression is not restricted to the wing, suggesting that Dei functions as a general genetic switch, which is turned on wherever a sticky cell-identity is determined and integrin-based adhesion is required.

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There are no randomized, controlled, trial-based indications regarding safe anesthetic drugs to be used perioperatively in MRCD carriers. Consultation among geneticists, anesthesiologists, intensivists, and surgeons is essential in patients with known/suspected metabolic syndrome for planning appropriate perioperative care.