TAF1B（TATA Box结合蛋白（TBP）相关因子）是调节rDNA活性、应激反应和细胞周期的RNA聚合酶。然而，TAF1B在肝细胞癌（HCC）进展中的功能尚不清楚。本研究旨在表征TAF1B在调节HCC中核仁应激的关键作用和分子机制。我们基于癌症基因组图谱（TCGA）数据库、临床肝细胞癌患者的肿瘤和癌旁组织样本以及典型肝细胞癌，分析了TAF1B在肝细胞癌中的差异表达和预后价值。我们通过TAF1B在HepG2和SMMC-7721细胞中的克隆形成、细胞凋亡和Western blotting（WB）检测凋亡标记蛋白来检测细胞增殖和凋亡的差异表达。同时，我们通过WB方法研究了TAF1B敲低对前启动复合物（PIC）功能的影响，通过Co-IP和ChIP实验证明了复合物之间的相互作用以及对rDNA活性的影响。免疫荧光染色实验测量了核仁应激标记蛋白的表达，荧光原位杂交实验证实了rDNA活性，qRT-PCR实验证明了前rRNA水平的变化。在分子机制方面，我们研究了p53和miR-101在调节核仁应激和凋亡中的作用。最后，在裸鼠移植瘤模型中观察TAF1B敲低对肿瘤生长、细胞凋亡和p53表达的影响。我们发现TAF1B在肝细胞癌中高度表达，并与HCC患者的不良预后相关。TAF1B的减少通过p53-miR-101的正负反馈机制在肝细胞癌细胞中调节核仁应激和凋亡。RNA聚合酶I转录抑制诱导了miR-101的转录后激活，该过程依赖于p53。反过来，miR-101通过直接抑制p53介导的PARP通路形成负反馈。这些发现扩展了我们对TAF1B介导的核仁应激在肝细胞癌中的功能的理解，可能为探索HCC中潜在治疗靶点提供新的生物标志物。版权所有 © 2023 Chen、Gao、Jiang、Sheng、Wu、Zheng、Zhai、Yuan、Liu、Xu、Qian 、Xu、Fang和Zhang。

TAF1B (TATA Box Binding Protein (TBP)-Associated Factor) is an RNA polymerase regulating rDNA activity, stress response, and cell cycle. However, the function of TAF1B in the progression of hepatocellular carcinoma (HCC) is unknown.In this study, we intended to characterize the crucial role and molecular mechanisms of TAF1B in modulating nucleolar stress in HCC.We analyzed the differential expression and prognostic value of TAF1B in hepatocellular carcinoma based on The Cancer Genome Atlas (TCGA) database, tumor and paraneoplastic tissue samples from clinical hepatocellular carcinoma patients, and typical hepatocellular carcinoma. We detected cell proliferation and apoptosis by lentiviral knockdown of TAF1B expression levels in HepG2 and SMMC-7721 cells using clone formation, apoptosis, and Western blotting (WB) detection of apoptosis marker proteins. Simultaneously, we investigated the influence of TAF1B knockdown on the function of the pre-initiation complex (PIC) by WB, and co-immunoprecipitation (Co-IP) and chromatin immunoprecipitation (ChIP) assays verified the interaction between the complexes and the effect on rDNA activity. Immunofluorescence assays measured the expression of marker proteins of nucleolus stress, fluorescence in situ hybridization (FISH) assays checked the rDNA activity, and qRT-PCR assays tested the pre-rRNA levels. Regarding molecular mechanisms, we investigated the role of p53 and miR-101 in modulating nucleolar stress and apoptosis. Finally, the impact of TAF1B knockdown on tumor growth, apoptosis, and p53 expression was observed in xenograft tumors.We identified that TAF1B was highly expressed in hepatocellular carcinoma and associated with poor prognosis in HCC patients. TAF1B depletion modulated nucleolar stress and apoptosis in hepatocellular carcinoma cells through positive and negative feedback from p53-miR-101. RNA polymerase I transcription repression triggered post-transcriptional activation of miR-101 in a p53-dependent manner. In turn, miR-101 negatively feeds back through direct inhibition of the p53-mediated PARP pathway.These findings broaden our comprehension of the function of TAF1B-mediated nucleolar stress in hepatocellular carcinoma and may offer new biomarkers for exploring prospective therapeutic targets in HCC.Copyright © 2023 Chen, Gao, Jiang, Sheng, Wu, Zheng, Zhai, Yuan, Liu, Xu, Qian, Xu, Fang and Zhang.