The stem cell continuum: considerations on the heterogeneity and plasticity of marrow stem cells.
Traditional models of hematopoiesis have been hierarchical. Recent evidence showing that marrow stem cells are a cycling population and that the hematopoietic phenotype of these cells reversibly changes with cycle transit have suggested a continuum model of stem cell regulators. Studies on marrow cell conversion to lung cells have extended this continuum to cycle-related differentiation into nonhematopoietic stem cells. We postulate that stem cells transiting cell cycle continually change their chromatin structure, thus providing different windows of transcriptional opportunity and a continually changing phenotype. Final outcomes with this continuum model would be determined by the specific chromatin state of the cell and the presence of specific differentiation inducers.
Quesenberry
Peter J
PJ
Department of Research, The Center for Stem Cell Biology, Roger Williams Medical Center, Providence, RI 02908-4735, USA. pquesenberry@rwmc.org
Dooner
G
G
Dooner
M
M
Colvin
G
G
D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology*; D002453:Cell Cycle; D002454:Cell Differentiation; D006085:Graft Survival; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D033581:Stem Cell Transplantation / Q000639:trends*