## Abstract A temperature‐sensitive (ts) mutant of Chinese hamster cells (K12) is blocked at a step late in G~1~, required for the initiation of DNA synthesis. The ts lesion is recessive in interspecific hybrids.
DNA synthesis and mitosis in a temperature sensitive Chinese hamster cell line
✍ Scribed by D. H. Roscoe; Hildred Robinson; A. W. Carbonell
- Publisher
- John Wiley and Sons
- Year
- 1973
- Tongue
- English
- Weight
- 407 KB
- Volume
- 82
- Category
- Article
- ISSN
- 0021-9541
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Viability, DNA synthesis and mitosis have been followed in the temperature sensitive Chinese hamster cell mutant K12 under permissive and non‐permissive conditions. On incubation at 40°C cells retained their ability to form colonies at 33°C for 15 to 20 hours, but viability was lost gradually during the following 20 hours. When random cultures of K12 were shifted to 40°C the rate of DNA synthesis was normal for three to four hours but then decreased markedly, reaching 95% inhibition after 24 hours. Under the same conditions mitosis was inhibited after 15 hours. If cultures which had been incubated at 40°C for 16 hours were placed at 33°C the rate of DNA synthesis increased five hours after the shift down and mitosis 18 hours after. These results can be interpreted on the assumption that K12 at 40°C is unable to complete a step in the cell cycle which is essential for DNA synthesis and which occurs three to four hours before the start of S at 33°C.
📜 SIMILAR VOLUMES
## Abstract The Chinese hamster cell line K12 is temperature sensitive for the initiation of DNA synthesis and for the programming of rounding up to enter mitosis. Viability is lost expontentially after twelve hours at the non‐permissive temperature. This temperature sensitivity is reversed followi
## Abstract We have analyzed ongoing DNA replication in __ts__ BN‐2, a __dna__^−^ mutant of BHK‐21 cells (Nishimoto et al. '78). At the non‐permissive temperature of 39.5°C, inhibition of ^3^H‐thymidine into acid‐precipitable material begins 1 to 2 h after the cells are released from a block at the
## Abstract A temperature‐sensitive (ts) cell cycle mutant of Chinese hamster fibroblasts with a block in G~1~ was investigated. Attention was on the expression of the activity of three enzymes: ornithine decarboxylase (ODC), S‐adenosylmethionine decarboxylase (SAMDC), and thymidine kinase (TK). OD
## Abstract Cytosol thymidine kinase (TK) and deoxycytidylate (dCMP) deaminase formation was investigated in synchronized cultures of K12 Chinese hamster cells which have a temperature‐sensitive lesion affecting the initiation of DNA synthesis. Enzyme formation was found to be cycloheximide‐sensiti
## Abstract Hybrid clones were obtained between a mouse cell line (3TP) and a temperature‐sensitive Chinese hamster cell line (K12) unable to grow at 40° because of a __ts__ defect apparently located at the G1/S transition. The great majority of hybrid clones grew at 40°, showing the __ts__ defect