Department of Stem Cell Biology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa, Japan.
Stem Cells. 2017 Nov;35(11):2229-2238. doi: 10.1002/stem.2673. Epub 2017 Aug 8.
Ets-related transcription factor GA-binding protein alpha (GABPα), which is encoded by Gabpa, is expressed in a variety of cell types and is involved in cellular functions such as cell cycle regulation, apoptosis, and differentiation. Here, we generated Gabpa conditional knockout embryonic stem cells (ESCs) and characterized its cellular phenotypes. Disruption of Gabpa revealed that the proliferation of Gabpa-null ESCs was drastically repressed and cells started to die within 2 days. The repressed proliferation of Gabpa-null ESCs was recovered by artificially forced expression of GABPα. Expression analysis showed that p53 mRNA levels were comparable; however, p53 target genes, including Cdkn1a/p21, Mdm2, and Gadd45a, were upregulated and cell cycle-related genes, including Cyclin D1/D2 and Cyclin E1/E2, were downregulated in Gabpa-null ESCs. Interestingly, p53 and cleaved Caspase3 expressions were enhanced in the cells and reduced proliferation as well as cell death of Gabpa-null ESCs were rescued by either transfection of p53 RNAi or treatment of the p53 inhibitor pifithrin-α. These results suggest that GABPα inhibits the accumulation of p53 and is involved in the proliferation and survival of ESCs. Stem Cells 2017;35:2229-2238.
Ets 相关转录因子 GA 结合蛋白α（GABPα）由 Gabpa 编码，在多种细胞类型中表达，参与细胞周期调控、细胞凋亡和分化等细胞功能。在这里，我们生成了 Gabpa 条件性敲除胚胎干细胞（ESCs），并对其细胞表型进行了表征。Gabpa 的缺失显示 Gabpa 缺失的 ESCs 增殖受到严重抑制，细胞在 2 天内开始死亡。通过人工强制表达 GABPα，恢复了 Gabpa 缺失的 ESCs 的抑制增殖。表达分析表明 p53 mRNA 水平相当；然而，p53 靶基因，包括 Cdkn1a/p21、Mdm2 和 Gadd45a，上调，细胞周期相关基因，包括 Cyclin D1/D2 和 Cyclin E1/E2，下调 Gabpa 缺失的 ESCs。有趣的是，p53 和裂解 Caspase3 的表达在细胞中增强，并且 Gabpa 缺失的 ESCs 的增殖减少和细胞死亡被 p53 RNAi 的转染或 p53 抑制剂 pifithrin-α的处理挽救。这些结果表明 GABPα 抑制 p53 的积累，并参与 ESCs 的增殖和存活。干细胞 2017;35:2229-2238。
