An in situ analysis of Drosophila imaginal disc regeneration: pattern reorganisation occurs independently of cell proliferation. Sandra Diaz-Garcia, Antonio Baonza. Development and Genetics Dept, CBMSO-UAM (CSIC), Madrid, Spain.

   One of the most intriguing problems in developmental biology is how an organism can replace missing organs or portions of their bodies after injuries. This capacity, known as regeneration, is conserved across different phyla. The imaginal discs of Drosophila melanogaster provide a particularly well-characterised model system for analysing regeneration. Although this organism has been extensively used to study this process, the cellular and molecular mechanisms underlying regeneration remain unclear. We have developed a new method to study organ regeneration under physiological conditions using the imaginal discs of Drosophila as a model system. Using this method, we have revisited different aspects of organ regeneration in Drosophila. The results presented in this report suggest that during the initial stages of disc regeneration different processes occur, including wound healing, temporary loss of markers of cell fate commitment and pattern reorganisation. These processes occur even when cell proliferation has been arrested. Our data suggests that wingless plays only a minor role during the early stages of regeneration, and its expression is down-regulated in some regions of the wing discs as a consequence of a reduction in the activity of Notch signalling.