Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Shizuoka 431-3192, Japan.
Medical Education Center, Hamamatsu University School of Medicine, Shizuoka 431-3192, Japan.
Int J Mol Sci. 2021 Sep 16;22(18):10015. doi: 10.3390/ijms221810015.
The transcription factor GATA2 regulates gene expression in several cells and tissues, including hematopoietic tissues and the central nervous system. Recent studies revealed that loss-of-function mutations in are associated with hematological disorders. Our earlier in vitro studies showed that GATA2 plays an essential role in the hypothalamus-pituitary-thyroid axis (HPT axis) by regulating the genes encoding prepro-thyrotropin-releasing hormone (preproTRH) and thyroid-stimulating hormone β (TSHβ). However, the effect of GATA2 mutants on the transcriptional activity of their promoters remains unelucidated. In this study, we created five human mutations (, , , , and ) that were reported to be associated with hematological disorders and analyzed their functional properties, including transactivation potential and DNA-binding capacity toward the and the promoters. Three mutations (, , and ) within the C-terminal zinc-finger domain reduced the basal GATA2 transcriptional activity on both the and the promoters with a significant loss of DNA binding affinity. Interestingly, only the mutation reduced the GATA2 protein expression. Subsequent analysis demonstrated that the mutation possibly facilitated the GATA2 degradation process. R308P and S447R mutants exhibited decreased transcriptional activity under protein kinase C compared to the wild-type protein. In conclusion, we demonstrated that naturally occurring mutations impair the HPT axis through differential functional mechanisms in vitro.
转录因子 GATA2 调节包括造血组织和中枢神经系统在内的几种细胞和组织中的基因表达。最近的研究表明， 的功能丧失突变与血液系统疾病有关。我们之前的体外研究表明，GATA2 通过调节编码促甲状腺素释放激素前体 (preproTRH) 和促甲状腺激素 β (TSHβ) 的基因，在下丘脑-垂体-甲状腺轴 (HPT 轴) 中发挥重要作用。然而，GATA2 突变体对其启动子转录活性的影响仍未阐明。在这项研究中，我们创建了五个与血液系统疾病相关的人类 突变体（、、、、和），并分析了它们的功能特性，包括反式激活潜力和对 和 启动子的 DNA 结合能力。位于 C 末端锌指结构域内的三个突变体（、和）降低了 GATA2 对 和 启动子的基础转录活性，DNA 结合亲和力显著丧失。有趣的是，只有 突变降低了 GATA2 蛋白表达。随后的分析表明， 突变可能促进了 GATA2 的降解过程。与野生型蛋白相比，R308P 和 S447R 突变体在蛋白激酶 C 作用下的转录活性降低。总之，我们证明了天然存在的 突变通过体外不同的功能机制损害 HPT 轴。
