HeLa cells resistant to bromodeoxyuridine and deficient in thymidine kinase activity

✍ Scribed by Saul Kit; D. R. Dubbs; Peter M. Frearson

• Publisher: John Wiley and Sons
• Year: 1966
• Tongue: French
• Weight: 697 KB
• Volume: 1
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910010105

✦ Synopsis

The deficiency in thymidine kinase activity of HeLa BU-100 cells was not due to negative feedback inhibition by high levels of BUdR or to interference with the thymidine kinase assay by inhibitors or competing enzymes in the HeLa BU-100 cell extracts. Followikg 5 weekly passages in nzedia lacking BUdR, the HeLa BU-100 cells did not exhibit increased thymidine kinase activity. Moreover, mixtures of extracts from HeLa S3 and HeLa BU-100 cells displayed a thymidine kinase activity equivalent to the sum of the activities of extracts prepared, respectively, from the HeLa S3 and HeLa BU-100 cells.

Radioautographic studies have shown that after HeLa S3 cells were incubated for 6 hours with thymidine-$H, 35-45 per cent of the nuclei were heavily labeled with radioactivity. However, fewer HeLa BU-100 cells displayed labeled nuclei and the nuclei were only lightly labeled.

HeLa BU-100 cell extracts contained normal amounts of thymidylate synthetase, thymidylate kinase, and uridine kinase activities. Follo wing irzfection by vaccinia virus, high levels of thymidine kinase activity were induced in HeLa BU-100 cells.