Inhibition of replicon initiation and DNA elongation in Chinese hamster ovary cells by treatment at 45. 5 degrees C

Journal Article · Tue Jun 01 04:00:00 EDT 1982 · NIDA Res. Monogr.; (United States)

OSTI ID:6187569

Wong, R S; Dewey, W C

Heat treatment of Chinese hamster ovary cells at 45.5 degrees C for 15 minutes resulted in the inhibition of both the replicon initiation and the DNA elongation processes. Analysis of the DNA made after treatment showed that for up to 30 minutes after hyperthermia, there was a significant increase (45-80% above control level) in the amount of labeled DNA less than or equal to 40S in size and having a distinct peak of 20S. Therefore, elongation of 20S molecules into larger molecules was inhibited or slowed down. These small molecules did not accumulate when recovery times were longer than 30 minutes. The DNA made after 120 and 240 minutes postheat incubation was larger than control size and indicated that, although replicon initiation was still inhibited, elongation between replicons into 120S molecules could take place. However, their subsequent elongation into parental-size molecules was inhibited. The same delay in DNA elongation seen in cells examined immediately after treatment was still observed in cells heated and allowed to recover for 30 minutes. Also, after 30 minutes of recovery, heated cells still had more newly synthesized DNA in the single-stranded fraction than did control cells, which indicates that DNA elongation within a replicon is delayed for at least 30 minutes after heating. Furthermore, at 4 hours after heating, the inhibition of elongation of clusters of replicons into parental molecules prevailed.

• Research Organization: Department of Radiology and Radiation Biology, Colorado State University, Ft. Collins
• OSTI ID: 6187569
• Journal Information: NIDA Res. Monogr.; (United States), Journal Name: NIDA Res. Monogr.; (United States) Vol. 61; ISSN MIDAD
• Country of Publication: United States
• Language: English

Related Subjects

560111* -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BODY TEMPERATURE
CELL CULTURES
COMPARATIVE EVALUATIONS
DNA
DNA REPLICATION
HAMSTERS
HYPERTHERMIA
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MOLECULAR BIOLOGY
NORTH AMERICA
NUCLEIC ACID REPLICATION
NUCLEIC ACIDS
ORGANIC COMPOUNDS
RADIOSENSITIVITY
REACTION KINETICS
RODENTS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
USA
VERTEBRATES