A model for the control of crystal cell development by MLF/DnaJ-1, Lz, and Notch.

<p>In wild-type conditions, <i>lz</i> expression is induced in crystal cell precursors and Lz protein gradually accumulates thanks to its interaction with MLF/DnaJ-1. At the same time, ligand-independent Notch signaling promotes crystal cell growth and survival. Once it reaches a sufficient level, Lz represses <i>Notch</i> transcription. This leads to a down-regulation of Notch signaling, thereby limiting crystal cell growth and promoting the death (rupture) of mature crystal cells. In conditions where Lz activity is impaired (decreased expression or lack of stabilization by MLF/DnaJ-1), crystal cells do not differentiate properly and Notch activity is maintained at high levels, which causes the accumulation of a higher number of Lz⁺ cells and their overgrowth.