Lineages, quantal cell cycles, and the generation of cell diversity

Abstract

Most theories of determination or differentiation assume that embryonic cells differ from mature cells. Embryonic cells are thought to have metastable control mechanisms. These labile controls are believed to become progressively more stabilized as the cells differentiate. Zygote, blastula, neural plate, limb bud, somite, or ‘stem’ cells are conceived of as undifferentiated, totipotent, or multipotential cells. As such, these cells supposedly have available for activation a larger repertoire of phenotypic programmes than their progeny. A necessary corollary to this view is that the activation of one particular phenotypic programme out of the many available is a function of instructive exogenous inducing molecules.

The Interferon-induced Hyporesponsive State in Variant and Parental L Cells: A Requirement for Cell Division

“…Similar hypotheses for special quantal cell cycles during differentiation have been proposed by others (e.g. Holtzer & Holtzer, 1976).…”

Chondrogenic potential of chick embryonic calvaria: II. Matrix calcium may repress cartilage differentiation

“…Our preferred hypothesis is that the physical presence of such a rigid, calcified matrix encasing calvarial cells with chondrogenic potential may restrict or completely prohibit events essential for cartilage differentiation and histogenesis; such events include cell migration, cell aggregation, and cell-cell interactions. Space constraints could also restrict quanta1 cell division, postulated to be a key factor for chondrogenic differentiation (Holtzer et al, 1975). In this manner, a calcified matrix may mask the effects on calvarial cells of endogenous factors including growth factors, cartilage, and osteoinductive agents, as well as certain ECM components which may be stimulatory for chondrogenesis (for review, see Centrella and Canalis, 1985).…”

Transdetermination: Drosophila imaginal disc cells exhibit stem cell-like potency

“…Such cell-cycle changes may allow for transcriptional reprogramming and TD. This idea is based on the fact that as stem cells progress through the cell cycle their decision to become a stem cell or commit to a particular lineage is most vulnerable during S phase, when there are dramatic structural changes made to the chromatin, resulting in numerous transcriptional changes (Holtzer et al, 1975;Quesenberry, Colvin, & Lambert, 2002).…”