Although BTB–zinc finger (BTB-ZF) transcription factors control the differentiation of multiple hematopoietic and immune lineages, how they function is poorly understood. The BTB-ZF factor Thpok controls intrathymic CD4 + T cell development and the expression of most CD4 + and CD8 + lineage genes. Here, we identify the nucleosome remodeling and deacetylase (NuRD) complex as a critical Thpok cofactor. Using mass spectrometry and coimmunoprecipitation in primary T cells, we show that Thpok binds NuRD components independently of DNA association. We locate three amino acid residues within the Thpok BTB domain that are required for both NuRD binding and Thpok functions. Conversely, a chimeric protein merging the NuRD component Mta2 to a BTB-less version of Thpok supports CD4 + T cell development, indicating that NuRD recruitment recapitulates the functions of the Thpok BTB domain. We found that NuRD mediates Thpok repression of CD8 + lineage genes, including the transcription factor Runx3 , but is dispensable for Cd4 expression. We show that these functions cannot be performed by the BTB domain of the Thpok-related factor Bcl6, which fails to bind NuRD. Thus, cofactor binding critically contributes to the functional specificity of BTB-ZF factors, which control the differentiation of most hematopoietic subsets.

中文翻译：

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Thpok 的 NuRD 复合物募集介导 CD4 + T 细胞谱系分化

尽管 BTB-锌指 (BTB-ZF) 转录因子控制着多种造血和免疫谱系的分化，但人们对它们的功能知之甚少。BTB-ZF 因子 Thpok 控制胸腺内 CD4+T 细胞发育和大多数 CD4 的表达+和CD8+谱系基因。在这里，我们将核小体重塑和脱乙酰酶 (NuRD) 复合物确定为关键的 Thpok 辅助因子。在原代 T 细胞中使用质谱法和共免疫沉淀法，我们表明 Thpok 独立于 DNA 结合结合 NuRD 成分。我们在 Thpok BTB 结构域内找到了 NuRD 结合和 Thpok 功能所需的三个氨基酸残基。相反，将 NuRD 组件 Mta2 合并到无 BTB 版本的 Thpok 的嵌合蛋白支持 CD4+T 细胞发育，表明 NuRD 募集概括了 Thpok BTB 域的功能。我们发现 NuRD 介导 Thpok 对 CD8 的抑制+谱系基因，包括转录因子运行x3, 但对于镉表达。我们证明这些功能不能由 Thpok 相关因子 Bcl6 的 BTB 域执行，它不能绑定 NuRD。因此，辅助因子结合对 BTB-ZF 因子的功能特异性有重要贡献，从而控制大多数造血亚群的分化。