HP1γ is required for G9a/GLP coactivator function with the glucocorticoid receptor in Nalm6 cells

Using a genome-wide analysis, we demonstrated that HP1γ is selectively required for GC-regulated expression of GR target genes that require G9a and GLP, consistent with our previous finding that automethylated G9a and GLP recruit HP1g to specific genomic GR binding sites. We examined whether HP1g is required for GC-induced expression of the genes that require coactivators, G9a and GLP, by depleting HP1g, G9a and GLP in Nalm6 cells using shRNA and examined gene expression changes at 8 hour dexamethasone (dex) treatment compared with ethanol treatment as a control. shRNA for a nonspecific sequence (shNS) followed by 8h of dex treatment was performed as control.

本研究通过全基因组分析（genome-wide analysis）证实，HP1γ可选择性参与依赖G9a与GLP的糖皮质激素（Glucocorticoid, GC）调控的糖皮质激素受体（Glucocorticoid Receptor, GR）靶基因表达过程，该结果与我们此前的研究发现一致：自身甲基化的G9a与GLP能够将HP1γ招募至特定基因组的GR结合位点。为探究HP1γ是否参与依赖辅激活因子G9a与GLP的GC诱导基因表达，我们通过短发夹RNA（short hairpin RNA, shRNA）在Nalm6细胞中敲低HP1γ、G9a及GLP的表达；随后以地塞米松（dexamethasone, dex）处理8小时，对比乙醇处理对照组的基因表达变化。此外，我们设置了转染非特异性序列短发夹RNA（shNS）并经8小时dex处理的对照组。