Adult stem cells are fundamental for physiological tissue renewal and regeneration after injury. The failure of stem cells to substitute dead or damaged cells is seen as one mechanism that limits the longevity of organisms. Planarian flatworms provide a unique model system to investigate in vivo the molecular machinery that controls adult stem cell functions in tissue renewal and repair. The extraordinary ability of planarians to regenerate whole animals from very small body fragments is in fact strictly associated with the unlimited growth potential of pluripotent stem cells, referred to as neoblasts. Neoblasts are distributed throughout the body and constantly undergo division to support continuous turnover of all specialized cell types. Moreover, upon amputation, these cells activate extensive proliferation to form the regenerative blastema, from which missing parts are regenerated. Damage or reduction in number of neoblasts deeply affects regeneration and planarian survival. Even though some progress has been made in identifying the genes that regulate self-renewal capacity and commitment of these cells, little is known about how these cells support continuous proliferative activity and long-term stability, maintaining control of cell division. I discuss evidence suggesting that Djmot, a planarian mortalin-like gene, significantly contributes to the mechanisms that regulate unlimited growth potential of stem cells in vivo, and I advance the hypothesis that its product plays a major role in keeping the activity of p53 under control in these cells.
Mortalin and stem cells: a study from planarians
BATISTONI, RENATA
2012-01-01
Abstract
Adult stem cells are fundamental for physiological tissue renewal and regeneration after injury. The failure of stem cells to substitute dead or damaged cells is seen as one mechanism that limits the longevity of organisms. Planarian flatworms provide a unique model system to investigate in vivo the molecular machinery that controls adult stem cell functions in tissue renewal and repair. The extraordinary ability of planarians to regenerate whole animals from very small body fragments is in fact strictly associated with the unlimited growth potential of pluripotent stem cells, referred to as neoblasts. Neoblasts are distributed throughout the body and constantly undergo division to support continuous turnover of all specialized cell types. Moreover, upon amputation, these cells activate extensive proliferation to form the regenerative blastema, from which missing parts are regenerated. Damage or reduction in number of neoblasts deeply affects regeneration and planarian survival. Even though some progress has been made in identifying the genes that regulate self-renewal capacity and commitment of these cells, little is known about how these cells support continuous proliferative activity and long-term stability, maintaining control of cell division. I discuss evidence suggesting that Djmot, a planarian mortalin-like gene, significantly contributes to the mechanisms that regulate unlimited growth potential of stem cells in vivo, and I advance the hypothesis that its product plays a major role in keeping the activity of p53 under control in these cells.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
