Cytoplasmic p53 contributes to the removal of uracils misincorporated by HIV-1 reverse transcriptase.
Cytoplasmic p53 contributes to the removal of uracils misincorporated by HIV-1 reverse transcriptase.
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细胞质 p53 有助于去除 HIV-1 逆转录酶错误掺入的尿嘧啶。
DOI：
10.1016/j.bbrc.2018.02.159
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发表时间：
2018
影响因子：
3.1
通讯作者：
M. Bakhanashvili
中科院分区：
文献类型：
--
作者：
Yossi Saragani;A. Hizi;G. Rahav;Sara Zaouch;M. Bakhanashvili
HIV感染细胞胞浆中的HIV-1逆转录酶(RT)有效地将非规范的dUTP插入到前病毒DNA中，并延伸以DU结尾的DNA。DUTP的错误结合会导致突变，尿嘧啶可以下调病毒基因的表达。然而，尿毒作用也可能保护HIV DNA不会在细胞质中自我整合。肿瘤抑制因子P53蛋白具有固有的3‘→5’外切酶活性，在HIV逆转录过程中为宿主来源的修复机制提供了一种潜在的修复机制，以防止各种错误的核苷酸错误掺入，导致碱基错配和掺入非规范核苷酸。由于校对活性的存在对于DNA合成的准确性是必不可少的，我们通过重组HIV-1RT(使用同基因的P53熟练和缺陷的HCT116 细胞)，阐明了细胞质P53在dUTP插入DNA过程中的潜在参与。生化数据表明，在HIV-1RT的DNA合成过程中，细胞质中的P53可以通过分子间途径，通过去除预先形成的3‘-末端DU，从而阻止3’-DU末端引物的进一步延伸，参与DNA损伤相关的修复机制。修复熟练的p53携带细胞的胞浆裂解物中的p53的特异性消耗减少了这一负面影响。因此，Nutlin处理的细胞中P53丰度的增加与增强的纠错功能相关，即去除被掺入的尿嘧啶。这些数据证实了P53作为潜在校对者的重要性，用于从HIV DNA中移除非规范的dUTP，从而防止dUTP误掺入HIV细胞类型特异性感染性的后果。
HIV-1 reverse transcriptase (RT) in the cytoplasm of HIV-infected cells efficiently inserts the non-canonical dUTP into the proviral DNA, and extends the dU-terminated DNA. The misincorporation of dUTP leads to mutagenesis, and uracils can down-regulate viral gene expression. However, uracilation might also protect HIV DNA from auto-integration in the cytoplasm. Tumor suppressor p53 protein, exhibiting inherent 3′→5′ exonuclease activity, provides a potential host-derived repair mechanism during HIV reverse transcription for the misincorporation of various wrong nucleotides, leading to both base-base mismatches and incorporated non-canonical ribonucleotides. Since the presence of proofreading activity is essential for DNA synthesis accuracy, we elucidated the potential involvement of cytoplasmic p53 in the U-editing activities during insertion of dUTP into DNA by recombinant HIV-1 RT (using isogenic p53-proficient and -deficient HCT116 cells). The biochemical data show that p53 in cytoplasm can participate through the intermolecular pathway in a dU-damage-associated repair mechanism by its ability to remove preformed 3′-terminal dUs, thus preventing further extension of 3′ dU-terminated primer during DNA synthesis by HIV-1 RT. The specific depletion of p53 from cytoplasmic lysates of repair-proficient p53-harboring cells reduced this negative effect. Accordingly, the increased abundance of p53 in nutlin-treated cells correlates with enhanced error-correction functions, namely, removal of incorporated uracil. The data substantiate the significance of p53 as a potential proofreader for removal of non-canonical dUTP from HIV DNA, thus preventing the consequences of dUTP misincorporation in cell-type specific infectivity of HIV.
影响因子：
5.4
作者：
Hu, Wei-Shau;Hughes, Stephen H
通讯作者：
Hughes, Stephen H