Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Department of Hematology, Cambridge Institute for Medical Research and Welcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom.
Elife. 2019 Jan 23;8:e40364. doi: 10.7554/eLife.40364.
The PLZF transcription factor is essential for osteogenic differentiation of hMSCs; however, its regulation and molecular function during this process is not fully understood. Here, we revealed that the locus encoding PLZF, is repressed by Polycomb (PcG) and H3K27me3 in naive hMSCs. At the pre-osteoblast stage of differentiation, the locus lost PcG binding and H3K27me3, gained JMJD3 recruitment, and H3K27ac resulting in high expression of PLZF. Subsequently, PLZF was recruited to osteogenic enhancers, influencing H3K27 acetylation and expression of nearby genes important for osteogenic function. Furthermore, we identified a latent enhancer within the locus itself that became active, gained PLZF, p300 and Mediator binding and looped to the promoter of the nicotinamide N-methyltransferase () gene. The increased expression of NNMT correlated with a decline in SAM levels, which is dependent on PLZF and is required for osteogenic differentiation.
PLZF 转录因子对于 hMSC 的成骨分化是必不可少的;然而,其在这个过程中的调控和分子功能尚未完全阐明。在这里,我们揭示了编码 PLZF 的 基因座在原始 hMSC 中被 Polycomb(PcG)和 H3K27me3 抑制。在分化的成骨前体细胞阶段,该基因座失去 PcG 结合和 H3K27me3,获得 JMJD3 的募集,以及 H3K27ac,导致 PLZF 的高表达。随后,PLZF 被募集到成骨增强子,影响 H3K27 乙酰化和附近对成骨功能重要的基因的表达。此外,我们在 基因座本身内鉴定出一个潜在的增强子,它变得活跃,获得了 PLZF、p300 和 Mediator 的结合,并与烟酰胺 N-甲基转移酶( )基因的启动子形成环。NNMT 的表达增加与 SAM 水平的下降相关,这依赖于 PLZF,并且是成骨分化所必需的。