Figure 4

A model for active-gene recruitment to the NPC. When repressed and inactive, an inducible gene exhibits nucleoplasmic diffusion with occasional transient sampling of the nuclear periphery and NPC. Upon transcriptional induction, the transcription machinery is recruited to the gene promoter and transcription is initiated. Appropriate RNA-binding proteins are recruited and deposited upon the nascent mRNA. The activated gene locus now contains many factors with an affinity for NPC-associated Sac3. Once the active locus samples the nuclear periphery after nascent transcription has begun, the gene is captured and constrained at the NPC via Sac3.