The histone acetyltransferase KAT6A is recruited to unmethylated CpG islands via a DNA binding winged helix domain [RNA-seq]. The histone acetyltransferase KAT6A is recruited to unmethylated CpG islands via a DNA binding winged helix domain [RNA-seq]

The lysine acetyltransferase KAT6A (MOZ, MYST3) belongs to the MYST family of chromatin regulators, facilitating histone acetylation. Dysregulation of KAT6A has been implicated in developmental syndromes and the onset of acute myeloid leukemia (AML). Previous work suggests that KAT6A is recruited to its genomic targets by a combinatorial function of histone binding PHD fingers, transcription factors and chromatin binding interaction partners. Here, we demonstrate that a winged helix (WH) domain at the very N-terminus of KAT6A specifically interacts with unmethylated CpG motifs. This DNA binding function leads to the association of KAT6A with unmethylated CpG islands (CGIs) genome-wide. Mutation of the essential amino acids for DNA binding completely abrogates the enrichment of KAT6A at CGIs. In contrast, deletion of a second WH domain or the histone tail binding PHD fingers only subtly influences the binding of KAT6A to CGIs. Overexpression of a KAT6A WH1 mutant has a dominant negative effect on H3K9 histone acetylation, which is comparable to the effects upon overexpression of a KAT6A HAT domain mutant. Taken together, our work revealed a previously unrecognized chromatin recruitment mechanism of KAT6A, offering a new perspective on the role of KAT6A in gene regulation and human diseases. Overall design: RNA-Seq of Control and KAT6A knockout mouse ES cells (2 replicates).

赖氨酸乙酰转移酶KAT6A（MOZ、MYST3）属于染色质调控因子MYST家族，可介导组蛋白乙酰化过程。KAT6A的失调与发育综合征及急性髓系白血病（AML）的发生密切相关。既往研究表明，KAT6A通过组蛋白结合PHD结构域（PHD fingers）、转录因子与染色质结合互作伴侣的协同功能被招募至其基因组靶位点。本研究证实，KAT6A N端极远端的翼螺旋（winged helix, WH）结构域可特异性结合未甲基化CpG基序。该DNA结合功能使KAT6A在全基因组范围内与未甲基化CpG岛（CGIs）相结合。对DNA结合所需关键氨基酸进行突变，可完全消除KAT6A在CpG岛处的富集。与之相反，缺失第二个WH结构域或组蛋白尾结合PHD结构域，仅会轻微影响KAT6A与CpG岛的结合。过表达KAT6A的WH1突变体可引发显性负效应，抑制H3K9组蛋白乙酰化，其效果与过表达KAT6A的组蛋白乙酰转移酶（HAT）结构域突变体相当。综上，本研究揭示了此前未被发现的KAT6A染色质招募机制，为理解KAT6A在基因调控与人类疾病中的作用提供了全新视角。实验设计总览：对对照组与KAT6A敲除小鼠胚胎干细胞（ES细胞）进行RNA测序（RNA-Seq），设置2个生物学重复。