Open AccessCell cycle related [ 3 H]thymidine uptake and its significance for the incorporation into DNA
Author(s) -
Naito K.,
Skog S.,
Tribukait B.,
Andersson L.,
Hisazumi H.
Publication year - 1987
Publication title -
cell proliferation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.647
H-Index - 74
eISSN - 1365-2184
pISSN - 0960-7722
DOI - 10.1111/j.1365-2184.1987.tb01329.x
Subject(s) - thymidine , dna , dna synthesis , cell cycle , biology , dna replication , cell , microbiology and biotechnology , chemistry , biochemistry
. Cellular uptake of [ 3 H]thymidine ([ 3 H]TdR) and incorporation into DNA of Ehrlich ascites tumour cells were studied in relation to the cell cycle by measuring the activity in the acid‐soluble and insoluble parts of the cell material. Cells were synchronized at various stages of the cell cycle using centrifugal elutriation. The degree of synchrony of the various cell fractions was measured by flow‐cytofluorometric DNA analysis. From the cellular uptake, the TdR triphosphate (dTTP) concentration of a mean cell in an unseparated cell population was calculated to be 20 × 10 ‐18 mol/cell. The pool activity of G 1 cells was unmeasurable but rose to maximum values at the border of the G 1 ‐S phase. It decreased again during G 2 . The [ 3 H]TdR incorporation into DNA was low during early S phase, reached a maximum value at two‐thirds of the S phase and decreased again during late S phase. These changes in DNA synthesis were not due to changes in the dTTP pool being a limiting factor. During maximum DNA synthesis, 10%× min ‐1 of the dTTP pool was utilized, at which time the pool size also decreased by about 30%. Changes in pool size during the cell cycle have to be taken into account when the results of incorporation of radioactive TdR into DNA are discussed.