p53 inhibits division following cellular damage. Cultured cells were found to express p53 protein following pulse labelling with radioisotopes, even at low doses normally used for growth and metabolic labelling studies. Some stem cells are exquisitely sensitive to radiation and thus p53 may have evolved as a major regulator of stem cell function. Therefore any genetic damage may be able to induce p53 expression, which in turn will affect the biochemical outcome of many experiments by both cell cycle arrest and other mechanisms. In some cases the use of radioisotopes may directly change the results of the experiment. This will require a careful re-evaluation of the current literature and experimental protocols utilising radioisotopes.

REFERENCES

Beck
H.-P.
(
1982
).
Radiotoxicity of incorporated [3H]thymidine. Consequences for the interpretation of FLM data of irradiated populations.
Cell Tissue Kinet
15
,
469
480
Cleaver
J. E.
,
Thomas
G. H.
,
Burki
H. J.
(
1972
).
Biological damage from intranuclear tritium: DNA strand breaks and their repair.
Science
177
,
996
968
Dover
R.
,
Potten
C. S.
(
1983
).
Cell cycle kinetics of cultured human epidermal keratinocytes.
J. Invest. Dermatol
80
,
423
429
Fritsche
M.
,
Haessler
C.
,
Brander
G.
(
1993
).
Induction of nuclear accumulation of the tumor-suppressor protein p53 by DNA-damaging agents.
Oncogene
8
,
307
318
Goodheart
C. R.
(
1961
).
Radiation dose calculation in cells containing intranuclear tritium.
Radiat. Res
15
,
767
773
Hall
P. A.
,
Menage
H. D.
,
Dover
R.
,
Hobbs
R. C.
,
McKee
P. M.
(
1992
).
High-levels of p53 protein in uv-irradiated normal human skin.
J. Pathol
168
,
203
207
Hume
W. J.
,
Potten
C. S.
(
1982
).
A long-lived thymidine pool in epithelial stem cells.
Cell Tissue Kinet
15
,
49
58
Kastan
M. B.
,
Onyekwere
O.
,
Sidransky
D.
,
Vogelstein
B.
,
Craig
R. W.
(
1991
).
Participation of p53 protein in the cellular response to DNA damage.
Cancer Res
51
,
6304
6311
Kastan
M. B.
,
Zhan
Q.
,
el-Deiry
W. S.
,
Carrier
F.
,
Jacks
T.
,
Walsh
W. V.
,
Plunkett
B. S.
,
Vogelstein
B.
,
Fornace
A. J.
Jr.
(
1992
).
A mammalian cell cycle checkpoint pathway utilizing p53 and GADD45 is defective in ataxia-telangiectasia.
Cell
71
,
587
97
Kisieleski
W. E.
,
Samuels
L. D.
,
Hiley
P. C.
(
1964
).
Dose-effect measurements of radiation following administration of tritiated thymidine.
Nature
202
,
458
459
Kuerbitz
S. J.
,
Plunkett
B. S.
,
Walsh
W. V.
,
Kastan
M. B.
(
1992
).
Wild-type p53 is a cell cycle checkpoint determinant following irradiation.
Proc. Nat. Acad. Sci. USA
89
,
7491
7495
Lin
D.
,
Shields
M. T.
,
Ullrich
S. J.
,
Appella
E.
,
Mercer
W. E.
(
1992
).
Growth arrest induced by wild-type p53 protein blocks cells prior to or near the restriction point in late G1 phase.
Proc. Nat. Acad. Sci. USA
89
,
9210
–.
Møller
U.
,
Larsen
J. K.
,
Faber
M.
(
1974
).
The influence of injected tritiated thymidine on the mitotic circadian rhythm in the epithelium of the hamster cheek pouch.
Cell Tissue Kinet
7
,
231
239
Olsson
L.
(
1976
).
Effects of tritium labelled pyrimidine nucleosides in the mouse. 1. Cytodynamic pertubations in normal circadian rhthms after a single injection of 3H Thymidine.
Radiat. Res
68
,
258
271
Potten
C. S.
(
1977
).
Extreme sensitivity of some intestinal crypt cells to X and gamma irradiation.
Nature
269
,
518
521
Potten
C. S.
,
Wichmann
H. E.
,
Loeffler
M.
,
Dobek
K.
,
Major
D.
(
1982
).
Evidence for discrete cell kinetic subpopulations in mouse epidermis based on mathematical analysis.
Cell Tissue Kinet
15
,
305
329
Rheinwald
J. G.
,
Green
H.
(
1975
).
Serial cultivation of strains of human epidermal keratinocytes: the formation of keratinizing colonies from single cells.
Cell
6
,
331
344
Tishler
R. B.
,
Calderwood
S. K.
,
Coleman
C. N.
,
Price
B. D.
(
1993
).
Increases in sequence specific DNA binding by p53 following treatment with chemotherapeutic and DNA damaging agents.
Cancer Res
53
,
2212
2216
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