Boddu Prajwal C, Gupta Abhishek, Roy Rahul, De La Pena Avalos Barbara, Herrero Ane Olazabal, Neuenkirchen Nils, Zimmer Josh, Chandhok Namrata, King Darren, Nannya Yashuhito, Ogawa Seishi, Lin Haifan, Simon Matthew, Dray Eloise, Kupfer Gary, Verma Amit K, Neugebauer Karla M, Pillai Manoj M
bioRxiv. 2023 Feb 26:2023.02.25.530019. doi: 10.1101/2023.02.25.530019.
Transcription and splicing of pre-messenger RNA are closely coordinated, but how this functional coupling is disrupted in human disease remains unexplored. Here, we investigated the impact of non-synonymous mutations in SF3B1 and U2AF1, two commonly mutated splicing factors in cancer, on transcription. We find that the mutations impair RNA Polymerase II (RNAPII) transcription elongation along gene bodies leading to transcription-replication conflicts, replication stress and altered chromatin organization. This elongation defect is linked to disrupted pre-spliceosome assembly due to impaired association of HTATSF1 with mutant SF3B1. Through an unbiased screen, we identified epigenetic factors in the Sin3/HDAC complex, which, when modulated, normalize transcription defects and their downstream effects. Our findings shed light on the mechanisms by which oncogenic mutant spliceosomes impact chromatin organization through their effects on RNAPII transcription elongation and present a rationale for targeting the Sin3/HDAC complex as a potential therapeutic strategy.
Oncogenic mutations of SF3B1 and U2AF1 cause a gene-body RNAPII elongation defectRNAPII transcription elongation defect leads to transcription replication conflicts, DNA damage response, and changes to chromatin organization and H3K4me3 marksThe transcription elongation defect is linked to disruption of the early spliceosome formation through impaired interaction of HTATSF1 with mutant SF3B1.Changes to chromatin organization reveal potential therapeutic strategies by targeting the Sin3/HDAC pathway.
前体信使RNA的转录和剪接密切协调，但这种功能偶联在人类疾病中如何被破坏仍未得到探索。在这里，我们研究了SF3B1和U2AF1这两种癌症中常见的突变剪接因子的非同义突变对转录的影响。我们发现这些突变会损害RNA聚合酶II（RNAPII）沿基因体的转录延伸，导致转录-复制冲突、复制应激和染色质组织改变。这种延伸缺陷与由于HTATSF1与突变型SF3B1的结合受损而导致的剪接体组装前体破坏有关。通过无偏见筛选，我们确定了Sin3/HDAC复合物中的表观遗传因子，当对其进行调节时，可使转录缺陷及其下游效应正常化。我们的研究结果揭示了致癌突变剪接体通过其对RNAPII转录延伸的影响来影响染色质组织的机制，并为将Sin3/HDAC复合物作为潜在治疗策略提供了理论依据。
SF3B1和U2AF1的致癌突变导致基因体RNAPII延伸缺陷
RNAPII转录延伸缺陷导致转录复制冲突、DNA损伤反应以及染色质组织和H3K4me3标记的变化
转录延伸缺陷与通过HTATSF1与突变型SF3B1相互作用受损导致的早期剪接体形成破坏有关
染色质组织的变化揭示了通过靶向Sin3/HDAC途径的潜在治疗策略
