ABSTRACT
To fully comprehend the cellular factors which influence and/or control proliferation and differentiation during the aging process, it is necessary to study the cells’ interactions with one another and with their environment. To understand the nature of cell proliferation, specific cell markers and techniques are required to detect cells and their progeny. Cloning of cells in vitro from a defined source of tissue in vivo provides a suitable cellular system. The availability of such probes to specific proteins associated with nonproliferation and senescence is exciting, especially when one relates it to a protein called cyclin A. Perhaps statin also acts in a positive manner in regulating cessation of proliferation and terminal differentiation of cells. Genetic differences in onco-virus protein expression are evident during embryogenesis as well as in adult animals, and the expression of the protein may be influenced by the state of differentiation of the cell.
