Fig. 11

Model for the rescue of oral siphon regeneration by heat shock stress. A At normal growth temperature, oral siphon (OS) amputation or bisection into proximal and distal fragments results in the activation of a hypothetical regeneration factor (X) in proximal fragments, which initiates a stress response in the branchial sac vasculature triggering stem cell proliferation, progenitor cell migration, and distal regeneration. Distal fragments without X are unable to activate the stress response to regenerate after OS amputation. B A heat shock activates the stress response ectopically in the distal fragment triggering branchial sac stem cell proliferation and OS regeneration