G<sub>2</sub> repair in Nijmegen breakage syndrome
No Thumbnail Available
Date
1998
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Lymphocytes from a patient with the Nijmegen breakage syndrome (NBS/NBS) and his parents (NBS/+) have been analyzed to identify possible disturbances in chromosomal G(2) repair. The study included the determination of G(2) duration and the analysis of the chromosomal aberration frequencies in lymphocytes with/without caffeine and cyclohexemide (CHM) treatments during G(2), under control and X-irradiated conditions. Under control conditions, NBS/NBS lymphocytes showed that the basal chromosomal damage as well as the damage detected in G(2), with caffeine treatment, and the G(2) duration were higher than cells from an age-matched control. In X-irradiated NBS/NBS lymphocytes, the basal and G(2) chromosome aberration frequencies were higher than in the controls; however, no significant differences in G(2) duration were detected between these two type of cells.
Under X-irradiated conditions, NBS/+ lymphocytes showed that while the level of chromosomal damage in G(2) and the duration of this cell cycle phase were similar to the control cells, the frequency of unrepaired chromosomal lesions was higher than in the control lymphocytes. No significant differences in chromosomal damage and G(2) duration were detected in NBS/+ lymphocytes compared to the control cells, under control conditions.
CHM treatment, which induces an increase in G(2) duration, decreased the basal spontaneous and X-ray induced chromosome aberration frequency in NBS/NBS and NBS/+ lymphocytes. These results suggest that NBS lymphocytes might be affected by some disturbances in their ability to extend the G(2) duration, which may be influencing their DNA repair efficiency in this phase of the cell cycle.
Under X-irradiated conditions, NBS/+ lymphocytes showed that while the level of chromosomal damage in G(2) and the duration of this cell cycle phase were similar to the control cells, the frequency of unrepaired chromosomal lesions was higher than in the control lymphocytes. No significant differences in chromosomal damage and G(2) duration were detected in NBS/+ lymphocytes compared to the control cells, under control conditions.
CHM treatment, which induces an increase in G(2) duration, decreased the basal spontaneous and X-ray induced chromosome aberration frequency in NBS/NBS and NBS/+ lymphocytes. These results suggest that NBS lymphocytes might be affected by some disturbances in their ability to extend the G(2) duration, which may be influencing their DNA repair efficiency in this phase of the cell cycle.
Description
Keywords
caffeine, chromosomal aberrations, chromosome breakage syndromes, G(2) repair, NBS lymphocytes, X-rays irradiation