Abstract
The repair of UV-induced DNA damage in the phosphoenolpyruvate carboxykinase (PEPCK) gene was studied in primary cultures of hepatocytes isolated from young (6-month-old) and old (24-month-old) rats fed ad libitum and old rats fed a calorie-restricted diet. Incubation of the hepatocytes with cAMP rapidly induced PEPCK transcription and mRNA levels 4- to 5-fold. In absence of cAMP, the repair of the PEPCK fragment was similar in cultured hepatocytes isolated from young and old rats fed ad libitum. However, cAMP significantly increased the percentage of cyclobutane pyrimidine dimers (CPDs) removed from the PEPCK fragment 12 h after UV-irradiation in cultured hepatocytes isolated from young rats fed ad libitum. This increase was due to an increase in the repair of the transcribed strand of the PEPCK fragment. In contrast, cAMP did not increase the repair of the PEPCK fragment in cultured hepatocytes isolated from old rats fed ad libitum in spite of an increase in PEPCK transcription. Thus, it appears that the coupling of transcription and DNA repair is compromised in cultured hepatocytes isolated from old rats fed ad libitum. However, cultured hepatocytes isolated from old rats fed a calorie-restricted diet showed an induction in the rate of repair of the transcribed strand of the PEPCK fragment by cAMP that was similar to hepatocytes isolated from young rats fed ad libitum. Copyright (C) 1998 Elsevier Science B.V.
Original language | English (US) |
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Pages (from-to) | 37-48 |
Number of pages | 12 |
Journal | Mutation Research - DNA Repair |
Volume | 409 |
Issue number | 1 |
DOIs | |
State | Published - Oct 21 1998 |
Keywords
- Age
- DNA repair
- Dietary restriction
- PEPCK
- Primary cultures of rat hepatocyte
- Transcription
ASJC Scopus subject areas
- Molecular Biology
- Toxicology
- Genetics