Regeneration can take place across Drosophila compartments or segments with different Hox gene expression

Regeneration in Drosophila has primarily been studied in imaginal discs, which are organized into distinct compartments defined by strict lineage boundaries. While cells typically respect these borders, during regeneration cells can cross them to restore the original organ specification, which is determined by Hox genes. Although differences in Hox gene expression are known to segregate cell populations, the role of such differences as a potential barrier to regeneration remains unclear. We investigated this by analyzing two experimental settings: the analia (derived from the Hox-compound genital disc) and haltere discs with mutations in Ultrabithorax regulatory regions (bithorax or postbithorax). Our findings demonstrate that Hox gene differences are not an absolute impediment to regeneration across segments or compartments. However, we observed occasional regenerative limits, which were non-specifically enhanced in the postbithorax background.