在巨幼细胞贫血中，部分单链复制性DNA向双链DNA的转化会延迟。

Conversion of partially single-stranded replicating DNA to double-stranded DNA is delayed in megaloblastic anaemia.

作者信息

Wickremasinghe R G, Hoffbrand A V

出版信息

Biochim Biophys Acta. 1980 May 30;607(3):411-9. doi: 10.1016/0005-2787(80)90151-3.

Abstract

DNA from phytohaemagglutinin-stimulated lymphocytes which had been pulse-labelled for 1 min with [3H]deoxycytidine eluted as partially single-stranded DNA from columns of benzoylated napthoylated DEAE-cellulose. The label was transferred progressively into the double-stranded DNA fraction upon incubation in the presence of unlabelled deoxycytidine. The rate of transfer was slower in untreated lymphocytes from patients with megaloblastic anaemia than in corresponding control cells. A similar delay was also observed in normal lymphocytes treated with methotrexate or hydroxyurea. A close temporal correlation between the joining of Okazaki pieces (measured by alkaline sucrose gradients) and the transfer of the pulse label to double-stranded DNA suggested that the latter process represented the filling of gaps between Okazaki pieces. We suggest that this gap-filling step is retarded in megaloblastic anaemia and in cells treated with methotrexate or hydroxyurea.

摘要

用[3H]脱氧胞苷脉冲标记1分钟的植物血凝素刺激淋巴细胞的DNA，以部分单链DNA的形式从苯甲酰化萘甲酰化二乙氨基乙基纤维素柱上洗脱下来。在未标记的脱氧胞苷存在下孵育时，标记物逐渐转移到双链DNA部分。巨幼细胞贫血患者未经处理的淋巴细胞中标记物转移的速度比相应的对照细胞慢。在用甲氨蝶呤或羟基脲处理的正常淋巴细胞中也观察到类似的延迟。冈崎片段连接（通过碱性蔗糖梯度测量）与脉冲标记物向双链DNA转移之间存在密切的时间相关性，这表明后一过程代表了冈崎片段之间间隙的填补。我们认为，在巨幼细胞贫血以及用甲氨蝶呤或羟基脲处理的细胞中，这一间隙填补步骤受到了阻碍。