Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
Cell. 2013 Feb 28;152(5):969-83. doi: 10.1016/j.cell.2013.01.049.
Embedded in the nuclear envelope, nuclear pore complexes (NPCs) not only regulate nuclear transport but also interface with transcriptionally active euchromatin, largely silenced heterochromatin, as well as the boundaries between these regions. It is unclear what functional role NPCs play in establishing or maintaining these distinct chromatin domains. We report that the yeast NPC protein Nup170p interacts with regions of the genome that contain ribosomal protein and subtelomeric genes, where it functions in nucleosome positioning and as a repressor of transcription. We show that the role of Nup170p in subtelomeric gene silencing is linked to its association with the RSC chromatin-remodeling complex and the silencing factor Sir4p, and that the binding of Nup170p and Sir4p to subtelomeric chromatin is cooperative and necessary for the association of telomeres with the nuclear envelope. Our results establish the NPC as an active participant in silencing and the formation of peripheral heterochromatin.
嵌入核膜中的核孔复合体（NPCs）不仅调节核运输，还与转录活跃的常染色质、大部分沉默的异染色质以及这些区域之间的边界相互作用。目前尚不清楚 NPC 在建立或维持这些不同染色质区域方面发挥什么功能作用。我们报告称，酵母 NPC 蛋白 Nup170p 与基因组中包含核糖体蛋白和端粒基因的区域相互作用，在核小体定位和转录抑制中发挥作用。我们表明，Nup170p 在端粒基因沉默中的作用与其与 RSC 染色质重塑复合物和沉默因子 Sir4p 的关联有关，并且 Nup170p 和 Sir4p 与端粒外染色质的结合是协同的，并且对于端粒与核膜的关联是必需的。我们的结果确立了 NPC 作为沉默和形成外围异染色质的积极参与者。
