Pincheira J, Bravo M, Santos M J
Departamento de Biología Celular y Genética, Facultad de Medicina, Universidad de Chile, Santiago.
Clin Genet. 1998 Apr;53(4):262-7. doi: 10.1111/j.1399-0004.1998.tb02693.x.
Lymphocytes from a patient with the Nijmegen breakage syndrome (NBS/NBS) and his parents (NBS/+) have been analyzed to identify possible disturbances in chromosomal G2 repair. The study included the determination of G2 duration and the analysis of the chromosomal aberration frequencies in lymphocytes with/without caffeine and cyclohexemide (CHM) treatments during G2, 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 G2, with caffeine treatment, and the G2 duration were higher than cells from an age-matched control. In X-irradiated NBS/NBS lymphocytes, the basal and G2 chromosome aberration frequencies were higher than in the controls; however, no significant differences in G2 duration were detected between these two type of cells. Under X-irradiated conditions, NBS/+ lymphocytes showed that while the level of chromosomal damage in G2 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 G2 duration were detected in NBS/+ lymphocytes compared to the control cells, under control conditions. CHM treatment, which induces an increase in G2 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 G2 duration, which may be influencing their DNA repair efficiency in this phase of the cell cycle.
对一名患有奈梅亨断裂综合征（NBS/NBS）的患者及其父母（NBS/+）的淋巴细胞进行了分析，以确定染色体G2修复中可能存在的干扰。该研究包括测定G2期持续时间，以及分析在对照和X射线照射条件下，G2期有无咖啡因和环己酰亚胺（CHM）处理的淋巴细胞中的染色体畸变频率。在对照条件下，NBS/NBS淋巴细胞显示，基础染色体损伤以及在G2期用咖啡因处理后检测到的损伤，以及G2期持续时间均高于年龄匹配的对照细胞。在X射线照射的NBS/NBS淋巴细胞中，基础和G2期染色体畸变频率高于对照；然而，这两种类型的细胞之间在G2期持续时间上未检测到显著差异。在X射线照射条件下，NBS/+淋巴细胞显示，虽然G2期染色体损伤水平和该细胞周期阶段的持续时间与对照细胞相似，但未修复的染色体损伤频率高于对照淋巴细胞。在对照条件下，与对照细胞相比，NBS/+淋巴细胞在染色体损伤和G2期持续时间上未检测到显著差异。CHM处理可诱导G2期持续时间增加，降低了NBS/NBS和NBS/+淋巴细胞中基础自发和X射线诱导的染色体畸变频率。这些结果表明，NBS淋巴细胞在延长G2期持续时间的能力上可能受到某些干扰，这可能影响它们在细胞周期这个阶段的DNA修复效率。
