摘要目的检测UV和γ辐射对正常人外周血单核细胞的hHR21sp基因转录表达水平及hHR21sp在范可尼贫血（Fanconis Anemia FA）骨髓造血细胞和激活后的外周血单核细胞的转录表达情况,并分析hHR21sp基因在FA贫血发病机制中的作用。方法对范可尼贫血骨髓造血细胞和激活后的外周血单核细胞和正常人外周血单核细胞在UV或γ辐射后不同时间提取细胞总RNA，通过RT-PCR、Southern杂交、以β-actin为内参照放射影像对hHR21sp基因的转录表达水平进行检测,比较FA骨髓造血细胞与对照组差异和激活前后FA外周血单核细胞hHR21sp基因的表达水平。结果正常人外周血单核细胞与对照组比较在80j/m2 UV辐射hHR21sp表达于3h开始增加；在6h表达水平最高，与正常对照有2倍差异（P<0.05）；而γ-辐射5 Gy辐射6 h增加明显，在9h后有所降低与正常对照有2倍多差异（P<0.01）。可见FA病人骨髓造血细胞和对照组的hHR21sp基因表达水平有明显差异（P<0.05）。实验发现在激活后对FA病人外周血单核细胞检测，hHR21sp基因表达较对照组PB-MNC降低达2倍之多（P<0.05）。结论 hHR21sp表达水平在一定剂量电离辐射范围内随辐射剂量增加而增高，且对γ-辐射较UV辐射敏感，FA病人骨髓造血细胞和对照组的hHR21sp基因表达有明显差异，激活后的FA病人外周血单核细胞 hHR21sp基因表达降低显著，提示FA病人造血细胞hHR21sp基因表达缺陷，本研究结果为下一步深入研究FA发病机制提供实验基础。

abstractsObjective The radiation sensitive gene rad 21 of Schizosaccharomyces pombe is involved in the repair of double-stranded breaks in DNA and is essential for mitotic growth. The hHR21sp gene is its human homologue. In an attempt to investigate the role of hHR21sp in DNA repair, we studied the effects of UV and γ-ray irradiation on hHR21sp gene expression in normal human peripheral blood cells, and non-iradiated peripheral and bone marrow cells from Fanconi anemia (FA) patients who have shown DNA repair deficiency.Methods Total steady state RNA was extracted from peripheral blood cells and bone marrow. RNA transcripts were quantified after RT-PCR and Southern blot, phosphoimmage and autoradiogram analysis. The results were compared with control groups. Results hHR21sp expression was significantly increased from 3h to 9h after UV irradiation in peripheral blood cells from normal subjects at doses of 40-80j/m2 (P<0.05). hHR21sp was also up-regulated by γ-ray irradiation at 6h to 9h at dose of 1 to 5Gy (P<0.01), which was more significant than the UV irradiation. In the non-irradiated FA patient group, hHR21sp expression was decreased in bone marrow hematopoietic cells (P<0.05). After activation by PHA and IL-2, there was still a significant depression in expression by the FA patients peripheral blood cells compared with control groups (P<0.05). Conclusion hHR21sp was up-regulated at doses and times irradiated at the range tested in normal peripheral blood cells, and is more affected by γ-ray irradiation than UV irradiation. FA patient bone marrow hematopoietic cells and peripheral blood mononuclear cells showed down-regulation of hHR21sp expression. The results imply that defects in DNA repair via hHR21sp expression may play an important role in the pathogenesis of FA syndrome.