Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States.
Sci Rep. 2017 May 17;7(1):2009. doi: 10.1038/s41598-017-02120-5.
The placental transcription factors Distal-less 3 (DLX3) and Glial cell missing-1 (GCM1) have been shown to coordinate the specific regulation of PGF in human trophoblast cell lines. While both factors independently have a positive effect on PGF gene expression, when combined, DLX3 acts as an antagonist to GCM. Despite this understanding, potential mechanisms accounting for this regulatory interaction remain unexplored. We identify physical and functional interactions between specific domains of DLX3 and GCM1 in human trophoblast-derived cells by performing immunoprecipitation and mammalian one hybrid assays. Studies revealed that DLX3 binding reduced the transcriptional activity of GCM1, providing a mechanistic explanation of their functional antagonism in regulating PGF promoter activity. The DLX3 homeodomain (HD) was essential for DLX3-GCM1 interaction, and that the HD together with the DLX3 amino- or carboxyl-terminal domains was required for maximal inhibition of GCM1. Interestingly, a naturally occurring DLX3 mutant that disrupts the carboxyl-terminal domain leading to tricho-dento-osseous syndrome in humans displayed activities indistinguishable from wild type DLX3 in this system. Collectively, our studies demonstrate that DLX3 physically interacts with GCM1 and inhibits its transactivation activity, suggesting that DLX3 and GCM1 may form a complex to functionally regulate placental cell function through modulation of target gene expression.
胎盘转录因子 Distal-less 3（DLX3）和 Glial cell missing-1（GCM1）已被证明可以协调人滋养层细胞系中 PGF 的特异性调节。虽然这两个因子都独立地对 PGF 基因表达有正向影响，但当组合使用时，DLX3 则作为 GCM 的拮抗剂。尽管有了这样的认识，但潜在的解释这种调控相互作用的机制仍未被探索。我们通过进行免疫沉淀和哺乳动物单杂交测定，鉴定了人滋养层衍生细胞中特定的 DLX3 和 GCM1 结构域之间的物理和功能相互作用。研究表明，DLX3 结合降低了 GCM1 的转录活性，为它们在调节 PGF 启动子活性方面的功能拮抗提供了一种机制解释。DLX3 同源域（HD）是 DLX3-GCM1 相互作用所必需的，并且 HD 连同 DLX3 的氨基或羧基末端结构域对于 GCM1 的最大抑制是必需的。有趣的是，一种自然发生的 DLX3 突变体破坏了羧基末端结构域，导致人类的 trichodento-osseous 综合征，在该系统中，它表现出与野生型 DLX3 几乎相同的活性。总之，我们的研究表明，DLX3 与 GCM1 发生物理相互作用并抑制其转录激活活性，表明 DLX3 和 GCM1 可能形成复合物，通过调节靶基因表达来调节胎盘细胞功能。
