UV-induced DNA excision repair in rat fibroblasts during immortalization and terminal differentiation in vitro
UV-induced DNA excision repair was studied as DNA repair synthesis and dimer removal in rat fibroblast cultures, initiated from either dense or sparse inocula of primary cells grown from skin biopsies. During passaging in vitro an initial increase in DNA repair synthesis, determined both autoradiographically as unscheduled DNA synthesis (UDS) and by means of the BrdU photolysis assay as the number and average size of repair patches, was found to be associated with a morphological shift from small spindle-shaped to large pleiomorphic cells observed over the first twenty generations. In cell populations in growth crisis, a situation exclusively associated with thin-inoculum cultures in which the population predominantly consisted of large pleiomorphic cells, UDS was found to occur at a low level. After development of secondary cultures into immortal cell lines, both repair synthesis and morphology appeared to be the same as in the original primary spindle-shaped cells. At all passages the capacity to remove UV-induced pyrimidine dimers was found to be low, as indicated by the persistence of Micrococcus luteus UV endonuclease-sensitive sites. These results are discussed in the context of terminal differentiation and immortalization of rat fibroblasts upon establishment in vitro.
- Research Organization:
- TNO Institute for Experimental Gerontology, Rijswijk, The Netherlands
- OSTI ID:
- 6847488
- Journal Information:
- Exp. Cell Res.; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
FIBROBLASTS
DNA REPAIR
AUTORADIOGRAPHY
CELL CULTURES
CELL DIFFERENTIATION
ENDONUCLEASES
PYRIMIDINE DIMERS
RATS
REMOVAL
SKIN
THYMIDINE
ULTRAVIOLET RADIATION
ANIMAL CELLS
ANIMALS
AZINES
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BODY
CONNECTIVE TISSUE CELLS
DNA-ASE
ELECTROMAGNETIC RADIATION
ENZYMES
ESTERASES
HETEROCYCLIC COMPOUNDS
HYDROLASES
MAMMALS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PHOSPHODIESTERASES
PYRIMIDINES
RADIATIONS
RECOVERY
REPAIR
RIBOSIDES
RODENTS
SOMATIC CELLS
VERTEBRATES
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture