Cell reprogramming during regeneration in Drosophila: transgression of compartment boundaries

We discuss recent work about cellular reprogramming during regeneration of the imaginal discs of Drosophila. These contain various lineage blocks, compartments, which express distinct genetic programmes. It has been found that after massive damage to a compartment cells from a neighbour compartment can transgress the compartment border and contribute to its regeneration. The transgressing cells are genetically reprogrammed and acquire a new identity, a process facilitated by up regulation of the JNK pathway and transient loss of epigenetic control by the Pc-G and trx-G genes. The final acquisition of the new identity appears to be mediated by induction by neighbour cells, a phenomenon akin the Community Effect described for the specification of amphibian muscle cells.