Affiliations: 1) University of Illinois at Urbana Champaign; 2) New York University
Keywords: k. regeneration; f. pattern formation
Regeneration is a complex process that enables damaged tissues to be replenished and restored back to their correct morphology and function. As organs and tissues are prone to damage either by external forces or chronic illness, the identification of factors and mechanisms important for regeneration may have clinical significance. Our laboratory has described a regeneration-specific mechanism that stabilizes cell fate after damage, where the gene taranis maintains proper cell fate during late regeneration in Drosophila 3rd instar larval wing imaginal discs. Reduced Taranis levels allow damage-induced JNK signaling to overexpress engrailed. Overexpressed engrailed initiates a negative feedback loop that silences the engrailed locus, resulting in impaired patterning during regeneration, including posterior-to-anterior cell-fate transformations. Taranis prevents these posterior-to-anterior cell-fate changes by preventing engrailed overexpression. However, it is unclear which signals activate taranis expression during late regeneration, or how engrailed is regulated by JNK signaling or Taranis. Preliminary data showed that the pioneer transcription factor zelda was upregulated during late regeneration, and in a reduced zelda background, taranis reporter expression was also reduced, suggesting that Zelda may be an activator of taranis. Furthermore, zelda may have additional roles beyond activating taranis in the regenerating wing imaginal disc. Finally, we are also examining how engrailed expression is misregulated by JNK signaling, and how that misregulation is prevented by Taranis.