In mammalian cells, 5-methylcytosine (5mC) occurs in genomic double-stranded DNA (dsDNA) and is enzymatically oxidized to 5-hydroxymethylcytosine (5hmC), then to 5-formylcytosine (5fC), and finally to 5-carboxylcytosine (5caC). These cytosine modifications are enriched in regulatory regions of the genome. The effect of these oxidative products on five bZIP dimers (CREB1, ATF2, Zta, ATF3|cJun, and cFos|cJun) binding to five types of dsDNA was measured using protein binding microarrays. The five dsDNAs contain either cytosine in both DNA strands or cytosine in one strand and either 5mC, 5hmC, 5fC, or 5caC in the second strand. Some sequences containing the CEBP half-site GCAA are bound more strongly by all five bZIP domains when dsDNA contains 5mC, 5hmC, or 5fC. dsDNA containing 5caC in some TRE (AP-1)-like sequences, e.g., TGACTAA, is better bound by Zta, ATF3|cJun, and cFos|cJun.

中文翻译：

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bZIP 二聚体 CREB1、ATF2、Zta、ATF3|cJun 和 cFos|cJun 更喜欢与一些含有 5-甲酰胞嘧啶和 5-羧基胞嘧啶的双链 DNA 序列结合。

在哺乳动物细胞中，5-甲基胞嘧啶 (5mC) 出现在基因组双链 DNA (dsDNA) 中，被酶促氧化为 5-羟甲基胞嘧啶 (5hmC)，然后是 5-甲酰基胞嘧啶 (5fC)，最后是 5-羧基胞嘧啶 (5caC) . 这些胞嘧啶修饰富集于基因组的调控区域。使用蛋白质结合微阵列测量了这些氧化产物对五种 bZIP 二聚体（CREB1、ATF2、Zta、ATF3|cJun 和 cFos|cJun）与五种类型 dsDNA 结合的影响。五个 dsDNA 在两条 DNA 链中含有胞嘧啶或在一条链中含有胞嘧啶，在第二条链中含有 5mC、5hmC、5fC 或 5caC。当 dsDNA 包含 5mC、5hmC 或 5fC 时，一些包含 CEBP 半位点 GCAA 的序列与所有五个 bZIP 结构域的结合更牢固。在一些 TRE (AP-1) 样序列中含有 5caC 的 dsDNA，例如 TGACTAA，