Influence of growth state on relationship between nuclear template activity and in vitro 'ageing'

A reduction in nuclear template activity occurred in He125 cell cultures only after the expression of a reduction in growth ability. This suggests that these alterations in template activity are terminal events occurring late in the culture life span. Both the rate of loss of template activity and its qualitative aspects were influenced by the growth state of the cultures compared. Therefore, these factors should be taken into account in the analyses of the relationship between in vitro 'ageing' and nuclear template activity.