Transdetermination: Drosophila imaginal disc cells exhibit stem cell-like potency

Abstract

Drosophila imaginal discs, the primordia of the adult fly appendages, are an excellent system for studying developmental plasticity. Cells in the imaginal discs are determined for their disc-specific fate (wingness, legness) during embryogenesis. Disc cells maintain their determination during larval development, a time of extensive growth and proliferation. Only when prompted to regenerate do disc cells exhibit lability in their determined identity. Regeneration in the disc is mediated by a localized region of cell division, known as the regeneration blastema. Most regenerating disc cells strictly adhere to their disc-specific identity; some cells however, switch fate in a phenomenon known as transdetermination. Similar regeneration and transdetermination events can be induced in situ by misexpression of the signaling molecule wingless. Recent studies indicate that the plasticity of disc cells during regeneration is associated with high morphogen activity and the reorganization of chromatin structure. Here we provide both a historical perspective of imaginal disc transdetermination, as well as discuss recent findings on how imaginal disc cells acquire developmental plasticity and multipotency. We also highlight how an understanding of imaginal disc transdetermination can enhance an understanding of developmental potency exhibited by stem cells.

Drosophila as a model of wound healing and tissue regeneration in vertebrates

“…This result suggested that compensatory proliferation of imaginal disc tissue was taking place, in which the remaining living tissue could rescue the appropriate size of the disc. This ability of imaginal discs to regenerate after injury has been confirmed by other researches either in vivo and in vitro (Marsh and Theisen, 1999;McClure and Schubiger, 2007). Subsequent studies support the activation of this compensatory proliferation activity after apoptosis or injury triggering either tissue repair or normal growth processes and regulating organ size during development (Wells et al, 2006;Fan and Bergmann, 2008;Pérez-Garijo et al, 2009).…”

“…5A). This phenomenon, which is characterized by the change of cell identity by a reprogrammable mechanism, is known as transdetermination McClure and Schubiger, 2007;McClure et al, 2008). Transdetermination has been ascribed to the action of ectopic morphogens, which induce cells to activate incorrect signaling cascades Schubiger, 1998, 2003), chromatin modifications by PcG proteins or other factors (Lee et al, 2005;Klebes et al, 2005).…”

Concise Review: Alchemy of Biology: Generating Desired Cell Types from Abundant and Accessible Cells

“…(b) ''Transdetermination,'' in which a committed, but not yet fully differentiated, cell type or a progenitor cell is directly converted into another cell type without going back to or through a pluripotent stage. For example, alterations of imaginal disc cell fate can be seen in Drosophila melanogaster in the regenerating disc (e.g., a wing instead of a leg) [16]. (c) In ''serial heteromorphosis,'' similarly developed body parts or tissues, such as segments or appendages, develop in the wrong place during embryogenesis or regeneration in both Crustacea and insects.…”

“…It was found that specific genes were expressed at higher levels in the teratomas formed by iPS cells than in those formed by ES cells, and two of these genes, zymogen granule protein 16 and HORMA domain-containing 1, were specifically targeted in immune attacks. Epigenetic differences between iPS and ES cells and/or mutations in the coding sequences of iPS cells could result in the ectopic expression of these minor antigens and the immunogenicity of iPS cell derivatives [67,[83][84][85][86][87].…”

Advances in Pattern Formation: Signaling and Transcription

“…The classic and elegant transplantation experiments showing imaginal disc regeneration are one example. 12,13 They have recently published a paper on a genetic approach to find candidates specifically required in the regeneration process. 14 The screen reported at this meeting, concentrated on the genes that are activated in response to Wg upon the formation of a regeneration blastema.…”