Complementation of aprataxin deficiency by base excision repair enzymes
Complementation of aprataxin deficiency by base excision repair enzymes
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DOI：
10.1093/nar/gkv079
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发表时间：
2015-02-27
影响因子：
14.9
通讯作者：
Wilson, Samuel H.
中科院分区：
文献类型：
--
作者：
Caglayan, Melike;Horton, Julie K.;Wilson, Samuel H.
在碱基切除修复(BER)过程中，流产的结扎会导致含有5‘-腺苷脱氧核糖磷酸(5’-AMP-DRP)基团的修复中间产物被阻断。Aprataxin(AptX)能够移除AMP组，从而允许修复继续进行。早期的结果表明，纯化的DNA聚合酶β(polβ)通过裂解酶活性去除整个5‘-AMP-DRP基团，而FEN1(FEN1)则将5’-AMP-DRP基团连同一个或两个核苷酸一起去除。在这里，使用来自aptX缺乏的细胞系、人类1型动眼运动性失用共济失调(AOA1)和DT40鸡B细胞的细胞提取物，我们发现polβ和FEN1的酶活性显著且足够强，足以补充aptX缺乏。此外，olβ、aptX和FEN1在处理含DRP的5‘-腺化BER中间体过程中相互配合。最后，发现其他DNA聚合酶和具有DRP裂解酶活性的修复因子(pollambda、poliota、poltheta和Ku70)可以从BER中间体中去除5‘-腺基化-DRP基团。然而，这些酶的活性都弱于polβ和FEN1。
Abortive ligation during base excision repair (BER) leads to blocked repair intermediates containing a 5' -adenylated-deoxyribose phosphate (5'-AMP-dRP) group. Aprataxin (APTX) is able to remove the AMP group allowing repair to proceed. Earlier results had indicated that purified DNA polymerase beta (pol beta) removes the entire 5'-AMP-dRP group through its lyase activity and flap endonuclease 1 (FEN1) excises the 5'-AMP-dRP group along with one or two nucleotides. Here, using cell extracts from APTX-deficient cell lines, human Ataxia with Oculomotor Apraxia Type 1 (AOA1) and DT40 chicken B cell, we found that pol beta and FEN1 enzymatic activities were prominent and strong enough to complement APTX deficiency. In addition, pol beta, APTX and FEN1 coordinate with each other in processing of the 5'-adenylated dRP-containing BER intermediate. Finally, other DNA polymerases and a repair factor with dRP lyase activity (pol lambda, pol iota, pol theta and Ku70) were found to remove the 5'-adenylated-dRP group from the BER intermediate. However, the activities of these enzymes were weak compared with those of pol beta and FEN1.