Biologjia Online

It is generally thought that regenerating and transdetermining cells regress from a mature, committed state to an embryonic-like “younger” state, thereby increasing their developmental potential. By examining the cell cycle and growth characteristics of multipotent regenerating and transdetermining Drosophila leg imaginal disc cells, Sustar and Schubiger challenge this view. The authors document that regenerating cells progress directly from their current developmental state to a new one, without reverting to a “younger” cell cycle. By contrast, cells undergoing transdetermination are subject to transient and unique cell-cycle and cell-size changes, suggesting the existence of a novel, stem cell-like state, which is neither embryonic nor mature.