Luo Weifeng, Tripathi Manish K, Liu Qi, Chen Lei, Cowan Robert W, Daniel Juliet M, Yan Chi, Richmond Ann, Reynolds Albert B
Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA.
Departments of Medicine and Oncology, University of Texas Health Rio Grande Valley, McAllen, TX, USA.
Open Biol. 2025 Jun;15(6):240329. doi: 10.1098/rsob.240329. Epub 2025 Jun 4.
Kaiso (ZBTB33) is a transcription factor involved in mitotic clonal expansion and tumorigenesis in association with Adenomatous Polyposis Coli (APC) loss of heterozygosity. ENCODE data show strong overlap of the Kaiso promoter-binding site-encode-derived Kaiso-binding site (eKBS) and many other transcription factors, including BRCA1. Here we sought to determine whether BRCA1 is a component of the Kaiso enhanceosome that regulates gene transcription. Using proximal ligation assays, immunoprecipitation followed by mass spectrometry, luciferase assays and ChIP-seq experiments, we evaluated the association between BRCA1 and Kaiso. Kaiso nuclear extract immunoprecipitation experiments revealed that Kaiso associates strongly with genes involved in RNA splicing and processing. When Kaiso was not crosslinked to DNA, BRCA1 was not detected among Kaiso-binding proteins. However, overexpression of BRCA1 increased Kaiso-mediated gene transcription in luciferase assays in a Kaiso-dependent manner. Comparison of BRCA1 ChIP-seq and Kaiso ChIP-seq data from HCT116 cells revealed both BRCA1 and Kaiso commonly bind to the promoters of 379 genes. The most enriched term associated with these genes where BRCA1 and Kaiso bind their promoters is metabolism of RNA. Disease processes associated with these BRCA1/Kaiso gene promoters indicate that BRCA1 is functionally linked to a Kaiso-directed programme of RNAP2-mediated gene transcription and likely associated with colorectal cancer development and maintenance.
Kaiso(ZBTB33)是一种转录因子,与有丝分裂克隆扩增及肿瘤发生相关,与腺瘤性息肉病基因(APC)杂合性缺失有关。ENCODE数据显示,Kaiso启动子结合位点编码衍生的Kaiso结合位点(eKBS)与包括BRCA1在内的许多其他转录因子有很强的重叠。在此,我们试图确定BRCA1是否是调节基因转录的Kaiso增强体的一个组成部分。我们使用近端连接分析、免疫沉淀后质谱分析、荧光素酶分析和染色质免疫沉淀测序(ChIP-seq)实验,评估了BRCA1与Kaiso之间的关联。Kaiso核提取物免疫沉淀实验表明,Kaiso与参与RNA剪接和加工的基因强烈相关。当Kaiso未与DNA交联时,在Kaiso结合蛋白中未检测到BRCA1。然而,在荧光素酶分析中,BRCA1的过表达以Kaiso依赖的方式增加了Kaiso介导的基因转录。对来自HCT116细胞的BRCA1 ChIP-seq和Kaiso ChIP-seq数据的比较显示,BRCA1和Kaiso通常都与379个基因的启动子结合。与这些BRCA1和Kaiso结合其启动子的基因相关的最富集术语是RNA代谢。与这些BRCA1/Kaiso基因启动子相关的疾病过程表明,BRCA1在功能上与Kaiso指导的RNA聚合酶2介导的基因转录程序相关,可能与结直肠癌的发生和维持有关。