AJP - Cell Physiology, Vol 256, Issue 5 C977-C986, Copyright © 1989 by American Physiological Society
Cell subpopulations within proliferative and differentiating compartments of epidermis
J. H. Pavlovitch, M. Rizk-Rabin, M. Gervaise, P. Metezeau and D. Grunwald
Centre National de la Recherche Scientifique, UA 583, Hopital Necker-Enfants-Malades, Paris, France.
The heterogeneous population of newborn rat keratinocytes was separated
into different subgroups according to their cell size. The relation between
cell size, position in the cell cycle, RNA content, and proliferative
potential in culture was examined. A reserve stem cell population of Go/G1
cells, low in RNA, giving rise to colonies of undifferentiated phenotype in
cell culture, has been separated from more differentiated transit basal
cells. In the fractions of the larger cells, several subgroups, probably
corresponding to different stages of differentiation, were identified: G2M
cells with low RNA content, large S-phase cells rich in RNA, and small
Go/G1 cells low in RNA. The clonogenic cells from these fractions have
limited growth potential and give rise to moderately or terminally
differentiated colonies. The selective sorting of stem cell populations may
be useful for elucidating the mechanism of carcinogenesis in epidermis and
other proliferative tissues. Analysis of the relative proportions of cell
subpopulations represents a novel approach leading to the refinement of the
concepts of epidermal structure in physiological and pathological states.
It also could, by extension, shed new light on the behavior of other
proliferative tissues.
