Nonredundant and locus-specific gene repression functions of PRC1 paralog family members in human hematopoietic stem/progenitor cells.
Nonredundant and locus-specific gene repression functions of PRC1 paralog family members in human hematopoietic stem/progenitor cells.
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DOI：
10.1182/blood-2012-08-451666
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发表时间：
2013-03
期刊：
影响因子：
20.3
通讯作者：
V. van den Boom;M. Rozenveld-Geugien;F. Bonardi;Donatella Malanga;Djoke van Gosliga;A. Heijink;G. Viglietto;G. Morrone;F. Fusetti;E. Vellenga;J. Schuringa
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文献类型：
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作者：
V. van den Boom;M. Rozenveld-Geugien;F. Bonardi;Donatella Malanga;Djoke van Gosliga;A. Heijink;G. Viglietto;G. Morrone;F. Fusetti;E. Vellenga;J. Schuringa
Polycomb 组 (PcG) 蛋白 BMI1 是调节造血干细胞 (HSC) 和白血病干细胞自我更新的关键因素，并在 Polycomb 抑制复合物 1 (PRC1) 的背景下发挥作用。在人类中，PRC1 的 5 个亚基中的每一个都有旁系同源家族成员，其中许多成员存在于 PRC1 复合体中，可能以相互排斥的方式，表明 Polycomb 介导的沉默具有先前未预料到的复杂性。我们使用 RNA 干扰筛选方法来测试这些旁系同源物在人类造血中的功能。我们的数据表明各种旁系同源家族成员之间缺乏冗余，表明 PcG 蛋白之间存在功能多样化。通过使用体内生物素化标记方法，然后采用液相色谱-串联质谱法来鉴定 PcG 相互作用伙伴，我们证实了多个特定 PRC1 复合物的存在。我们发现CBX2是一种对HSC和祖细胞功能至关重要的非冗余CBX旁系同源物，可直接调节细胞周期蛋白依赖性激酶抑制剂p21的表达，独立于主要控制INK4A/ARF基因座表达的BMI1。综上所述，我们的数据表明不同的 PRC1 旁系同源家族成员具有非冗余和位点特异性基因调控活性，这对人类造血至关重要。
The Polycomb group (PcG) protein BMI1 is a key factor in regulating hematopoietic stem cell (HSC) and leukemic stem cell self-renewal and functions in the context of the Polycomb repressive complex 1 (PRC1). In humans, each of the 5 subunits of PRC1 has paralog family members of which many reside in PRC1 complexes, likely in a mutually exclusive manner, pointing toward a previously unanticipated complexity of Polycomb-mediated silencing. We used an RNA interference screening approach to test the functionality of these paralogs in human hematopoiesis. Our data demonstrate a lack of redundancy between various paralog family members, suggestive of functional diversification between PcG proteins. By using an in vivo biotinylation tagging approach followed by liquid chromatography-tandem mass spectrometry to identify PcG interaction partners, we confirmed the existence of multiple specific PRC1 complexes. We find that CBX2 is a nonredundant CBX paralog vital for HSC and progenitor function that directly regulates the expression of the cyclin-dependent kinase inhibitor p21, independently of BMI1 that dominantly controls expression of the INK4A/ARF locus. Taken together, our data show that different PRC1 paralog family members have nonredundant and locus-specific gene regulatory activities that are essential for human hematopoiesis.