Limb regeneration: Reconstitution of complex organs using specific tissue interactions

Limb regeneration in amphibians has been investigated for a long time because we still have not found a way to regenerate our body parts. Urodele amphibians generally have the ability to regenerate most of their organs. Limb regeneration has been investigated as a representative phenomenon of their high regeneration ability. Limb amputation in urodele amphibians causes regeneration blastema formation. A regeneration blastema is composed of undifferentiated cells called blastema cells. This blastema induction mechanism is the issue that has been the focus of study for a long time. Nerve tissue is known to be key for successful blastema formation and limb regeneration. Despite the importance of the nerve tissue in limb regeneration, its molecular description is not well established. Recently, a brand-new experimental system called an accessory limb model (ALM) was reported that is designed to reveal minimum and necessary tissue interaction including nerves. In this chapter, necessary tissue interactions for blastema induction in the ALM and related molecular descriptions are given.