Nuclear GPS for interchromosomal clustering

Abstract

Nuclear architecture and the relative position of a gene can play roles in the regulation of its expression. In this issue of Developmental Cell, Brickner et al. (2012) analyze nuclear global positioning of genes and reveal that the Put3 transcription factor functions with cis-encoded DNA elements and nuclear pore complexes to regulate interchromosomal gene clustering.

Figure 1. Interchromosomal clustering to subnuclear regions in S. cerevisiae and metazoans

A. In S. cerevisiae, the nucleus is composed of a nuclear periphery (red), a nucleolus (red outlined in dashed line) and the nucleoplasm (pink). The nuclear pore complex (NPC) and surrounding local environment are predicted to provide a subdomain permissive for gene expression (light green outlined in dashed line). Changes in the environment trigger genes with similar GRS elements to cluster together at the nuclear periphery (dark green outlined in dashed line). The localization mechanism requires the transcription factor Put3 and the nuclear pore complex (NPC) component Nup2. B. Metazoan nuclei have multiple nuclear bodies with distinct functions. The nuclear periphery (red) contains a heterochromatin and nuclear lamina meshwork alternating with heterochromatic exclusion zones and NPCs (light green outlined in dashed line). Nuclei can have from 1-4 nucleoli (red outlined in dashed line). In metazoans, nuclear rearrangements occur in response to environmental and developmental cues, wherein genes colocalize to specialized transcription factories (dark green outlined in dashed line). The molecular determinants for positioning in S. cerevisiae or metazoans remain to be fully elucidated (? symbol).