徐炳祥
(2023-03-30 13:13):
#paper doi: 10.1101/gad.333708.119. Genes Dev, 2020, Upon microbial challenge, human neutrophils undergo rapid changes in nuclear architecture and chromatin folding to orchestrate an immediate inflammatory gene program。中性粒细胞免疫应答过程中伴随着核型和染色质构象的剧烈变化,这些变化与免疫应答诱导的转录调控过程之间的关系尚不清楚。本文使用人类中性粒细胞为实验材料,以PMA和大肠杆菌为刺激源诱发免疫反应,以Hi-C测定应答前后的染色质空间构象并进行比较。结果显示,应答之前,炎性基因处于转录抑制的空间构象中,应答后这些基因所在区域发生常染色质化,由核周进入核内部,并与增强子靠近,这些过程与应答过程中转录的快速响应有关。这些染色质构象的重排可能是由cohesin驱动的。本研究处理时长已达3h,但仍未见染色质构象的大范围改变。这些结论提示虽然染色质构象的全基因组重构是罕见事件,其局部的改变依然有研究的价值。
Upon microbial challenge, human neutrophils undergo rapid changes in nuclear architecture and chromatin folding to orchestrate an immediate inflammatory gene program
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Abstract:
Differentiating neutrophils undergo large-scale changes in nuclear morphology. How such alterations in structure are established and modulated upon exposure to microbial agents is largely unknown. Here, we found that prior to encounter with bacteria, an armamentarium of inflammatory genes was positioned in a transcriptionally passive environment suppressing premature transcriptional activation. Upon microbial exposure, however, human neutrophils rapidly (<3 h) repositioned the ensemble of proinflammatory genes toward the transcriptionally permissive compartment. We show that the repositioning of genes was closely associated with the swift recruitment of cohesin across the inflammatory enhancer landscape, permitting an immediate transcriptional response upon bacterial exposure. We found that activated enhancers, marked by increased deposition of H3K27Ac, were highly enriched for cistromic elements associated with PU.1, CEBPB, TFE3, JUN, and FOSL2 occupancy. These data reveal how upon microbial challenge the cohesin machinery is recruited to an activated enhancer repertoire to instruct changes in chromatin folding, nuclear architecture, and to activate an inflammatory gene program.
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