Poly(ADP-ribose) synthesis in vitro programmed by damaged DNA. A comparison of DNA molecules containing different types of strand breaks.
Poly(ADP-ribose) synthesis in vitro programmed by damaged DNA. A comparison of DNA molecules containing different types of strand breaks.
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DOI：
10.1016/s0021-9258(19)70491-8
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发表时间：
1980-11
期刊：
影响因子：
--
通讯作者：
R. Benjamin;D. Gill
中科院分区：
文献类型：
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作者：
R. Benjamin;D. Gill
DNA支持多聚（ADP-核糖）合成的能力完全取决于其所含链断裂的数量和类型，而与序列无关。单链DNA是无效的。共价闭合的环状质粒DNA是无效的，但当它被酶消化时，它激活聚（ADP-核糖）聚合酶，与链断裂的数量成比例，表明聚合酶识别DNA末端。具有平末端的双链限制性片段比具有从3'末端延伸的未配对核苷酸的片段有效约3倍，并且比具有从5'末端延伸的未配对核苷酸的片段或具有单链断裂的质粒有效约10倍。所有类型的限制性片段在去除末端5 '-磷酸基团后变得更有效。这种特异性可能与聚（ADP-核糖）合成在修复DNA链断裂中的作用有关，因为那些被认为在体内更难修复的是更有效的刺激物。聚（ADP-核糖）聚合酶没有二价阳离子的要求时，提供冲洗结束的DNA片段，但镁可以提高其他类型的DNA的有效性，通过激活镁依赖性核酸酶。无效的DNA，如共价闭合的质粒或合成的均聚物，不能形成沃森-克里克双链体，显然与有效的DNA竞争，并微弱地抑制聚（ADP-核糖）的合成。
The ability of DNA is support poly(ADP-ribose) synthesis is completely dependent upon the number and type of strand breaks it contains and is independent of the sequence. Single-stranded DNA is ineffective. Covalently closed circular plasmid DNA is ineffective, but when it is enzymatically digested it activates poly(ADP-ribose) polymerase in proportion to the number of strand breaks, suggesting that the polymerase recognizes DNA ends. Double-stranded restriction fragments with flush ends are approximately 3 times more effective than are fragments with unpaired nucleotides extending from the 3' termini and about 10 times more effective than are either fragments with unpaired nucleotides extending from the 5' termini or plasmids with single-strand breaks. All types of restriction fragments become more effective upon removal of terminal 5'-phosphate groups. This specificity profile may relate to the proposed role of poly(ADP-ribose) synthesis in the repair of DNA strand breaks, for those which are assumed to be more difficult to repair in vivo are the more effective stimulators. Poly(ADP-ribose) polymerase has no divalent cation requirement when supplied with flush-ended DNA fragments, but magnesium may enhance the effective of other types of DNA by activating magnesium-dependent nucleases. Ineffective DNAs, such as covalently closed plasmids or synthetic homopolymers that are unable to form Watson-Crick duplexes, apparently compete with effective DNA and weakly inhibit poly(ADP-ribose) synthesis.