Notch signaling generates the “cut here line” on the cuticle of the puparium in Drosophila melanogaster

Summary

During a molt or eclosion, insects shed their cuticle, an extracellular matrix made by underlying epidermal cells, by cleavage along a defined line. This means that the “cut here line” is pre-formed on the cuticle, and its formation is indispensable for insect life. Here, we show that the proper formation of the operculum ridge (OR), which is the “cut here line” on the puparium (pupal case) of Drosophila melanogaster, involves Notch signaling activation in the epidermal cells just beneath the future OR region (OR-forming cells). The inhibition of Notch signaling causes defects in eclosion due to failure in OR cleavage, the chitin organization and several cuticular proteins localization, glucose dehydrogenase (Gld) activity, and OR-forming cell shape. Our findings provide the first insight into the molecular basis of the structure and formation of the “cut here line” on the cuticle.

Graphical abstract

Highlights

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  Notch signaling in OR-forming cells activated by Ser is required for OR formation

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  Unique structure formation at the future OR region requires Notch signaling

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  Gld activation by Notch signaling is required for OR maturation in the pupal stage

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  Elongated OR-forming cell shape is regulated by Notch signaling

Abstract

Entomology; Evolutionary developmental biology