Fig. 6.

Model for regulation of chromatin domains by MES-4, PRC2, and transcription regulatory regions. The genome is subdivided into domains of germ-line and broadly expressed genes (orange boxes), and domains of genes with developmentally or conditionally regulated expression (black boxes). MES-4 marks germ-line–expressed genes with H3K36me3, which inhibits deposition of H3K27me3 by PRC2 (23, 27), leading to demarcation of chromatin domains. Borders separating domains contain long intergenic regions enriched for TF binding (colored ovals); these regulatory regions may play a role in domain separation.