97 Oral - Stem Cells, Regeneration, and Tissue Repair
Friday April 08, 10:45 AM - 11:00 AM

Authors:
Douglas Terry; Can Zhang; Joanna Wardwell-Ozgo; Colby Schweibenz; Ken Moberg

Affiliation: Emory University

Keywords:
k. regeneration; j. other signaling pathways

Ecdysone steroid hormone (Ec) signaling is required to drive Drosophila developmental transitions and to promote growth of larval imaginal discs. Previous studies investigating imaginal wing disc regeneration have demonstrated the importance of inhibiting systemic Ec production to delay development and allow time for regeneration to occur. However, local roles for Ec signaling within regenerating tissues are not well understood. Based on our observation that Ec-responsive transcriptional reporters can be induced locally in injured larval wing discs, we have tested elements of the Ec pathway for roles in regeneration. We find that local knockdown of the Ec biosynthetic enzyme phantom (phm) during injury is sufficient to impair wing disc regeneration, and that local knockdown of the Ec-degradation enzyme cyp18a1 reciprocally enhances regeneration. In parallel, we find that injury induces a transient ring of Ec receptor (EcR) activity encircling the regenerating blastema which can be blocked by phm knockdown. In the absence of this EcR-activity pulse, we find a failure of intra-organ growth inhibition as cells within the uninjured compartments of the wing disc fail to slow their proliferation. Further, injured animals with phm knockdown lack a robust injury-induced developmental delay, while cyp18a1 knockdown has the opposite effect of extending injury-induced developmental delay. We will discuss mechanistic links between local Ec/EcR and signals produced by injured tissues that act systemically to control tissue homeostasis.