染色质修饰,包括Polycomb组蛋白在赖氨酸27(H3K27me)上的组蛋白H3甲基化,在维持细胞命运中起着广泛保守的作用。不同的染色质组织修饰物(色度)结构域蛋白充当组蛋白甲基化状态的“读者”。然而,了解chromo结构域之间的功能关系及其在基因表达模式遗传中的作用仍然具有挑战性。这里,我们鉴定出两种色素结构域蛋白,CEC-1和CEC-6,作为秀丽隐杆线虫中H3K27me的潜在读者,它们具有不同的表达模式并有助于不同的表型。cec-1和cec-6都与另一个色素结构域基因发生遗传相互作用,cec-3,H3K9甲基化的读者。cec-1和cec-3的组合丢失导致成年人的发育缺陷,从而导致健康下降。此外,cec-6和cec-3的损失令人惊讶地导致跨代生育能力的逐步丧失,“致命种系”表型。我们的结果提供了H3K27me和H3K9me异染色质途径之间功能补偿的证据,并表明组蛋白甲基化阅读器有助于体细胞发育和跨代适应度。
Chromatin modifications, including methylation of histone H3 at lysine 27 (H3K27me) by the Polycomb group proteins, play a broadly conserved role in the maintenance of cell fate. Diverse chromatin organization modifier (chromo) domain proteins act as \"readers\" of histone methylation states. However, understanding the functional relationships among chromo domains and their roles in the inheritance of gene expression patterns remains challenging. Here, we identify two chromo-domain proteins, CEC-1 and CEC-6, as potential readers of H3K27me in Caenorhabditis elegans, where they have divergent expression patterns and contribute to distinct phenotypes. Both cec-1 and cec-6 genetically interact with another chromo-domain gene, cec-3, a reader of H3K9 methylation. Combined loss of cec-1 and cec-3 leads to developmental defects in the adult that result in decreased fitness. Furthermore, loss of cec-6 and cec-3 surprisingly leads to a progressive loss of fertility across generations, a \"mortal germline\" phenotype. Our results provide evidence of functional compensation between H3K27me and H3K9me heterochromatin pathways, and show that histone methylation readers contribute to both somatic development and transgenerational fitness.