title: The cellular aging of rat fibroblasts in vitro is a differentiation process.
abstract: Cellular aging of diploid rat fibroblasts in vitro occurs as the result of a three-stage differentiation sequence, taking place in the morphologically recognizable differentiating cell compartment of the fibroblast stem cell system. Simultaneously with an age-dependent morphological differentiation there is an age-dependent biochemical differentiation of the fibroblasts. In cell strains with the genetic background Lewis, the cellular differentiation state, the major histocompatibility complex composition (H-1) and the H-1 complex-controlled expression of endogenous type C viruses determine the ultimate fate of the senescent cell, leading either to cellular degeneration or to cellular neoplastic transformation.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D002999:Clone Cells; D003094:Collagen / Q000032:analysis; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000502:physiology*; D006649:Histocompatibility Antigens / Q000032:analysis; D007700:Kinetics; D051381:Rats; D013997:Time Factors
chemical_list: D006649:Histocompatibility Antigens; D003094:Collagen