Section of Experimental Haematology, Leeds Institute of Cancer Studies and Pathology, University of Leeds, Wellcome Trust Brenner Building, St. James's University Hospital, Leeds LS9 7TF, UK.
J Mol Cell Biol. 2013 Oct;5(5):308-22. doi: 10.1093/jmcb/mjt023. Epub 2013 Aug 9.
Differentiation is a multistep process tightly regulated and controlled by complex transcription factor networks. Here, we show that the rate of differentiation of common myeloid precursor cells increases after depletion of CTCF, a protein emerging as a potential key factor regulating higher-order chromatin structure. We identified CTCF binding in the vicinity of important transcription factors regulating myeloid differentiation and showed that CTCF depletion impacts on the expression of these genes in concordance with the observed acceleration of the myeloid commitment. Furthermore, we observed a loss of the histone variant H2A.Z within the selected promoter regions and an increase in non-coding RNA transcription upstream of these genes. Both abnormalities suggest a global chromatin structure destabilization and an associated increase of non-productive transcription in response to CTCF depletion but do not drive the CTCF-mediated transcription alterations of the neighbouring genes. Finally, we detected a transient eviction of CTCF at the Egr1 locus in correlation with Egr1 peak of expression in response to lipopolysaccharide (LPS) treatment in macrophages. This eviction is also correlated with the expression of an antisense non-coding RNA transcribing through the CTCF-binding region indicating that non-coding RNA transcription could be the cause and the consequence of CTCF eviction.
分化是一个受复杂转录因子网络紧密调控的多步骤过程。在这里，我们表明，在耗尽 CTCF 后，常见的髓系前体细胞的分化速度会增加，CTCF 是一种新兴的潜在关键调节因子，可调节高级染色质结构。我们鉴定了在调节髓系分化的重要转录因子附近的 CTCF 结合，并表明 CTCF 耗竭会影响这些基因的表达，与观察到的髓系承诺加速一致。此外，我们观察到所选启动子区域内组蛋白变体 H2A.Z 的丢失以及这些基因上游非编码 RNA 转录的增加。这两种异常都表明，由于 CTCF 耗竭，整个染色质结构不稳定，并伴随着非生产性转录的增加，但不会驱动邻近基因的 CTCF 介导的转录改变。最后，我们在脂多糖（LPS）处理的巨噬细胞中，检测到 Egr1 基因座处 CTCF 的瞬时逐出，与 Egr1 表达峰相关。这种逐出也与通过 CTCF 结合区域转录的反义非编码 RNA 的表达相关，表明非编码 RNA 转录可能是 CTCF 逐出的原因和结果。
