HMGN2 represses gene transcription via interaction with transcription factors Lef-1 and Pitx2 during amelogenesis

作者：Steven Eliason, Dan Su, Flavia Oliveira Pinho, Zhao Sun, Zichao Zhang, Xiao Li, Mason Sweat, Shankar Rengasamy Venugopalan, Bing He, Michael Bustin, Brad A. Amendt · 发表于：Journal of Biological Chemistry · 年份：2022 · DOI：10.1016/j.jbc.2022.102295 · 被引用次数：11 · 研究领域：Bone and Dental Protein Studies、Cancer-related gene regulation、dental development and anomalies

The chromatin-associated high mobility group protein N2 (HMGN2) cofactor regulates transcription factor activity through both chromatin and protein interactions. Hmgn2 expression is known to be developmentally regulated, but the post-transcriptional mechanisms that regulate Hmgn2 expression and its precise roles in tooth development remain unclear. Here, we demonstrate that HMGN2 inhibits the activity of multiple transcription factors as a general mechanism to regulate early development. Bimolecular fluorescence complementation, pull-down, and coimmunoprecipitation assays show that HMGN2 interacts with the transcription factor Lef-1 through its HMG-box domain as well as with other early development transcription factors, Dlx2, FoxJ1, and Pitx2. Furthermore, EMSAs demonstrate that HMGN2 binding to Lef-1 inhibits its DNA-binding activity. We found that Pitx2 and Hmgn2 associate with H4K5ac and H3K4me2 chromatin marks in the proximal Dlx2 promoter, demonstrating Hmgn2 association with open chromatin. In addition, we demonstrate that microRNAs (miRs) mir-23a and miR-23b directly target Hmgn2, promoting transcriptional activation at several gene promoters, including the amelogenin promoter. In vivo, we found that decreased Hmgn2 expression correlates with increased miR-23 expression in craniofacial tissues as the murine embryo develops. Finally, we show that ablation of Hmgn2 in mice results in increased amelogenin expression because of increased Pitx2, Dlx2, Lef-1, and FoxJ1 tran...