May growth be regulated by systematic, stepwise collapse of DNA? A new hypothesis for the understanding of growth kinetics.
Cultured human and animal cells are predestined to undergo irreversible functional decrement that mimic age change in the whole organism. The underlying mechanism of this process, however, has not yet been discovered. A new hypothesis is introduced: The secondary structure of DNA is not stabile per se. It needs additional material surrounding it such as histones and non-histone proteins ("external stabilization"). In case of dissociations between the DNA and its additional stabilizer, well-defined localized break-downs of the chromatin structure will take place, which may happen predominantly during DNA replication. During subsequent cell divisions the number of break-downs will increase. Thus, higher molecular density will be reached which modifies not only the regulation of gene expression but also reduces the velocity of further cell division. A final state of density will be reached, where further replication is no longer possible.
D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000235:genetics*; D006128:Growth; D006801:Humans; D007700:Kinetics; D008954:Models, Biological
D002843:Chromatin; D004247:DNA