中文摘要：

PcG（polycomb group）蛋白作为一种表观遗传修饰系统,在动物和植物中具有保守性.从功能上讲,PcG蛋白可以分为PRC1（polycomb repressive complex 1）和PRC2（polycomb repressivecomplex 2）两个核心蛋白复合体.PRC2含有组蛋白甲基化酶的活性,而PRC1在泛素连接酶E3介导的组蛋白泛素化中发挥作用,二者通过对组蛋白的修饰控制靶基因转录.近来研究表明,PcG蛋白对干细胞数量维持和命运转变有重要的调控作用,其成员表达失调或缺失导致许多恶性肿瘤的发生或导致植物细胞丧失分化能力、形成愈伤组织.本文简要综述了PcG蛋白的组成及其在干细胞调控中的作用.

英文摘要：

Polycomb group（PcG） proteins form an epigenetic modification system that is conserved in animals and plants.The system is functionally divided into two major core multiprotein complexes： PRC1（polycomb repressive complex 1） and PRC2（polycomb repressive complex 2）.PRC2 exerts a histone methyltransferase activity,while PRC1 plays a role as an E3 ubiquitin ligase for histone.Both PRC1 and PRC2 control the targeted gene transcription through histone modification.Recent studies have demonstrated that PcG proteins play a key role in the maintenance of stem cells and cells fate determination.The deregulation or deficiency of PcGs members leads to cancer malignancy or cause the loss of cell differentiation,and also causes the formation of callus-like structures in plants.Here,the components of PcG proteins were briefly introduced and their roles in the regulation of stem cells were discussed.