ABSTRACT
The strange assortment of growth-regulated genes, there is no question that the identification of such genes is an important approach. There are three main reasons for studying growth-related genes. The first reason is to identify genes which control cell proliferation and which define the intracellular pathway from growth factor to DNA synthesis. Second, the mechanisms of regulation of any growth-related genes can give insight into this pathway. Thirdly, the expression of growth-related genes represents a series of intracellular events. The term “expression” is being used in one of its accepted usages, i.e., as in steady-state levels of cytoplasmic mRNA. Finally, Tsuji et al. found that heat-shock proteins were still inducible in senescent human diploid fibroblasts. It seems reasonably well established that senescent human diploid fibroblasts respond to growth factors with the expression of growth-regulated genes in a manner that is not different from that of young cells.
