FOXK2 transcription factor is a novel G/T-mismatch DNA binding protein
FOXK2 transcription factor is a novel G/T-mismatch DNA binding protein
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DOI：
10.1093/jb/mvq004
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发表时间：
2010-05-01
影响因子：
2.7
通讯作者：
Nakamura, Michio
中科院分区：
文献类型：
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作者：
Fujii, Yoshito;Nakamura, Michio
DNA错配修复是预防突变的重要机制。我们报道了 HL60 细胞系中存在一种需要严格 DNA 序列的新型 G/T 错配 DNA 结合蛋白 (nGTBP)。在本报告中，我们将 FOXK2 转录因子鉴定为 nGTBP。通过筛选人脑表达文库，获得了 FOXK2 片段，它是唯一对 G/T 错配 DNA 具有特异性结合活性的克隆。 FOXK2 的重组叉头结构域特异性识别 G/T 错配 DNA。叉头结构域还识别次黄嘌呤/T和G/尿嘧啶，它们分别源自A/T和G/C的环外氨基的脱氨基作用。使用 HL60 细胞核提取物和针对 FOXK2 的抗体进行的电泳迁移率变动分析 (EMSA) 分析导致 FOXK2 与 G/T 错配 DNA 的排他性结合。此外，FOXK2 与 G/T 错配 DNA 的结合亲和力高于“匹配”FOXK2 共有 DNA。因此，我们认为 FOXK2 是一种 G/T 错配 DNA 结合蛋白和脱氨基 DNA 结合蛋白。
DNA mismatch repair is an important mechanism in the prevention of mutations. We reported the existence in the HL60 cell line of a novel G/T-mismatch DNA-binding protein (nGTBP) requiring strict DNA sequences. In this report, we identify the FOXK2 transcription factor as the nGTBP. FOXK2 fragments were obtained as the only clones with specifically binding activity to the G/T-mismatch DNA by screening of a human brain expression library. The recombinant forkhead domain of FOXK2 specifically recognized the G/T-mismatch DNA. The forkhead domain also recognized hypoxanthine/T and G/uracil, derived from the deamination of the exocyclic amino groups of A/T and G/C, respectively. An electrophoretic mobility shift assay (EMSA) analysis using HL60 cell nuclear extract and antibody raised against FOXK2 resulted in the exclusive binding of FOXK2 to G/T-mismatch DNA. Furthermore, FOXK2 bound to G/T-mismatch DNA with higher affinity than 'match' FOXK2 consensus DNA. We therefore propose that FOXK2 is a G/T-mismatch DNA-binding protein and a deaminated DNA-binding protein.