Scaffold attachment factor (SAFB) 1 and its homologue SAFB2 are multifunctional proteins that are involved in various cellular mechanisms, including chromatin organization and transcriptional regulation, and are also corepressors of estrogen receptor alpha (ERα). Both SAFBs are expressed at high levels in the brain. However, the distributions of SAFB1 and SAFB2 have yet to be characterized in detail and it is unclear whether both proteins interact with ERα in the brain. In this study, we investigated the expression and distribution of both SAFBs and their interaction with ERα in adult male rat brain. Immunohistochemical staining showed that SAFB1 and SAFB2 have a similar distribution pattern and are widely expressed throughout the brain. Double-fluorescence immunohistochemical and immunocytochemical analyses in primary cultures showed that the two SAFB proteins are localized in nuclei of neurons, astrocytes, and oligodendrocytes. Of note, SAFB2 was also found in cytoplasmic regions in these cell lineages. Both SAFB proteins were also expressed in ERα-positive cells in the medial preoptic area (MPOA) and arcuate and ventromedial hypothalamic nuclei. Co-immunoprecipitation experiments revealed that both SAFB proteins from the MPOA reciprocally interact with endogenous ERα. These results indicate that, in addition to a role in basal cellular function in the brain, the SAFB proteins may serve as ERα corepressors in hormone-sensitive regions.

中文翻译：

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支架附着因子B：在大鼠脑中的分布和与ERα的相互作用。

支架附着因子（SAFB）1及其同源物SAFB2是涉及多种细胞机制（包括染色质组织和转录调控）的多功能蛋白，并且还是雌激素受体α（ERα）的核心抑制剂。两种SAFB均在大脑中高水平表达。然而，SAFB1和SAFB2的分布尚未详细描述，尚不清楚两种蛋白是否与大脑中的ERα相互作用。在这项研究中，我们调查了成年雄性大鼠脑中SAFBs的表达和分布以及它们与ERα的相互作用。免疫组织化学染色显示SAFB1和SAFB2具有相似的分布模式，并在整个大脑中广泛表达。在原代培养物中的双荧光免疫组织化学和免疫细胞化学分析表明，两种SAFB蛋白位于神经元，星形胶质细胞和少突胶质细胞核中。值得注意的是，在这些细胞谱系的细胞质区域中也发现了SAFB2。两种SAFB蛋白也在视前内侧区域（MPOA）以及弓状和腹膜下丘脑核的ERα阳性细胞中表达。免疫共沉淀实验表明，来自MPOA的两种SAFB蛋白都与内源性ERα相互作用。这些结果表明，除了在大脑的基础细胞功能中发挥作用外，SAFB蛋白还可以在激素敏感区域中充当ERα的核心抑制剂。在这些细胞谱系的细胞质区域中也发现了SAFB2。两种SAFB蛋白也在视前内侧区域（MPOA）以及弓状和腹膜下丘脑核的ERα阳性细胞中表达。免疫共沉淀实验表明，来自MPOA的两种SAFB蛋白都与内源性ERα相互作用。这些结果表明，除了在大脑的基础细胞功能中发挥作用外，SAFB蛋白还可以在激素敏感区域中充当ERα的核心抑制剂。在这些细胞谱系的细胞质区域中也发现了SAFB2。两种SAFB蛋白也在视前内侧区域（MPOA）以及弓状和腹膜下丘脑核的ERα阳性细胞中表达。免疫共沉淀实验表明，来自MPOA的两种SAFB蛋白都与内源性ERα相互作用。这些结果表明，除了在大脑的基础细胞功能中发挥作用外，SAFB蛋白还可以在激素敏感区域中充当ERα的核心抑制剂。