TY - JOUR
T1 - Regulation of human thymidine kinase during the cell cycle
AU - Sherley, J. L.
AU - Kelly, T. J.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1988
Y1 - 1988
N2 - As an approach to defining the molecular basis for the periodic expression of thymidine kinase activity during the cell cycle, we have examined properties of the cytosolic enzyme in cycling HeLa cells synchronized by centrifugal elutriation and mitotic selection. By immunoblot analyses with a specific antiserum raised against the purified HeLa enzyme, we have demonstrated that changes in the levels of thymidine kinase activity reflect similar changes in the levels of thymidine kinase polypeptide. In contrast, the steady state levels of thymidine kinase mRNA show relatively small changes during the cell cycle. Using pulse labeling methods, we have shown that the synthetic rate of thymidine kinase protein is about 10-fold greater in S phase than in G1 phase, indicating that the efficiency of translation of thymidine kinase mRNA increases as cells begin DNA replication. In addition, the stability of thymidine kinase protein dramatically decreases upon cell division, resulting in the rapid clearance of the enzyme from newly divided G1 cells. Thus, two different post-transcriptional mechanisms largely account for the periodic behavior of the enzyme activity during the cell cycle.
AB - As an approach to defining the molecular basis for the periodic expression of thymidine kinase activity during the cell cycle, we have examined properties of the cytosolic enzyme in cycling HeLa cells synchronized by centrifugal elutriation and mitotic selection. By immunoblot analyses with a specific antiserum raised against the purified HeLa enzyme, we have demonstrated that changes in the levels of thymidine kinase activity reflect similar changes in the levels of thymidine kinase polypeptide. In contrast, the steady state levels of thymidine kinase mRNA show relatively small changes during the cell cycle. Using pulse labeling methods, we have shown that the synthetic rate of thymidine kinase protein is about 10-fold greater in S phase than in G1 phase, indicating that the efficiency of translation of thymidine kinase mRNA increases as cells begin DNA replication. In addition, the stability of thymidine kinase protein dramatically decreases upon cell division, resulting in the rapid clearance of the enzyme from newly divided G1 cells. Thus, two different post-transcriptional mechanisms largely account for the periodic behavior of the enzyme activity during the cell cycle.
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M3 - Article
C2 - 3372530
AN - SCOPUS:0023951483
SN - 0021-9258
VL - 263
SP - 8350
EP - 8358
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 17
ER -