Expression data from Ezh2-null leukemic cells

The polycomb group (PcG) proteins function in gene silencing through histone modifications. They form chromatin-associated multiprotein complexes, termed polycomb repressive complex (PRC) 1 and PRC2. These two complexes work in a coordinated manner in the maintenance of cellular memories through transcriptional repression of target genes. EZH2 is a catalytic component of PRC2 and trimethylates histone H3 at lysine 27 to transcriptionally repress the target genes. PcG proteins have been characterized as general regulators of stem cells, but recent works also unveiled their critical roles in cancer. Purified leukemic cells from BM of recipient mice transplanted with wild-type and Ezh2-/- leukemic cells transformed with MLL-AF9 leukemic fusion gene were subjected to RNA extraction and hybridization on Affymetrix microarrays.

多梳蛋白家族（polycomb group, PcG）通过组蛋白修饰介导基因沉默过程。它们可形成结合于染色质的多蛋白复合物，即多梳抑制复合物（polycomb repressive complex, PRC）1与PRC2。这两类复合物通过对靶基因的转录抑制协同维持细胞记忆。EZH2是PRC2的催化组分，能够将组蛋白H3的赖氨酸27位点进行三甲基化修饰，从而实现对靶基因的转录抑制。既往研究将PcG蛋白定义为干细胞的通用调控因子，而近期研究则揭示了其在癌症发生中的关键作用。本研究将经MLL-AF9白血病融合基因转化的野生型与Ezh2基因敲除（Ezh2-/-）白血病细胞移植至受体小鼠体内，随后从受体小鼠的骨髓（bone marrow, BM）中纯化白血病细胞，对其进行RNA提取，并在Affymetrix基因微阵列上完成杂交实验。