The pioneer transcription factor Zelda facilitates the exit from regeneration and restoration of patterning in Drosophila

For a damaged tissue to regenerate, the injured site must repair the wound, proliferate, and restore the correct patterning and cell types. We found that Zelda, a pioneer transcription factor largely known for its role in embryonic zygotic genome activation, is dispensable for normal wing development but crucial for wing disc patterning during regeneration. Impairing Zelda function during disc regeneration resulted in adult wings with a plethora of cell fate errors, affecting the veins, margins, and posterior compartment identity. Using CUT&RUN, we identified and validated targets of Zelda including the cell fate genes cut, Delta and achaete, which failed to return to their normal expression patterns upon loss of Zelda. In addition, Zelda controls expression of factors previously established to preserve cell fate during regeneration like taranis and osa, which stabilizes engrailed expression during regeneration, thereby preserving posterior identity. Finally, Zelda ensures proper expression of the integrins encoded by multiple edematous wings and myospheroid during regeneration to prevent blisters in the resulting adult wing. Thus, Zelda is crucial for maintaining cell fate and structural architecture of the regenerating tissue. Overall design: CUT&RUN was performed for the transcription factor Zelda during wing regeneration (2 days after damage) and normal wing development, which was endogenously GFP tagged. Experiment was performed with anti-GFP antibody (Abcam #ab290) in duplicates. As a control, w1118 regenerating and normally developing larave without any GFP tag were used with the anti-GFP antibody.