BioProject

Embedded in the nuclear envelope, nuclear pore complexes (NPCs) not only regulate nuclear transport, but also interface with both transcriptionally active euchromatin and largely silenced heterochromatin, as well as the boundaries between these regions. More...

Embedded in the nuclear envelope, nuclear pore complexes (NPCs) not only regulate nuclear transport, but also interface with both transcriptionally active euchromatin and 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. Here we report that the yeast NPC protein Nup170p interacts with specific regions of the genome containing ribosomal protein and subtelomeric genes. At these locations, Nup170p functions to establish normal nucleosome positioning and as a repressor of transcription. We show that the function 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 the formation of peripheral heterochromatin. Overall design: Two-color microarrays were performed using Agilent whole-genome Saccharomyces cerevisiae arrays (Agilent) to determine gene expression profiles in the nucleoporin mutant strains nup157∆, nup170∆, and nup188∆. Similar analyses were performed on PMET3-HA3-STH1 cells depleted of Sth1p for either 2 hrs (sth1-deplete 2hrs) or depleted of Sth1p for 8 hrs followed by reinduction of Sth1p for an additional 4 hrs (sth1-reinduction 4hr), as well as WT cells grown in the presence or absence of methionine. All experiments were performed with duplicate experimental and duplicate technical replicates of each condition as previously described (Wan et al., 2009). Less...