使用 MCE 產(chǎn)品發(fā)表高分文章集錦
Lipoamide purchased from MCE.
氨基酸重復擴增發(fā)生在 >20 種遺傳性人類疾病中，許多發(fā)生在轉錄因子 (TFs) 的固有無序結構域 (IDRs)。此類疾病與蛋白質聚集有關，但聚集物對病理的作用一直存在爭議。該研究報道了轉錄因子 HOXD13 (導致人類遺傳性多指癥) 中，丙氨酸的重復擴增改變了其相分離能力及與轉錄共激活因子共凝聚的能力。在體外和體內(nèi)，HOXD13 重復擴增擾亂了含 HOXD13 凝結物的成分，并且在小鼠多指模型中以細胞特異性方式改變了轉錄程序。同樣的，其他 TFs (HOXA13, RUNX2 和 TBP) 中與疾病相關的重復擴增也改變了其相分離。這些結果表明，轉錄凝聚物的非融合可能是對應疾病的病理基礎。研究人員提出了 TF IDRs 的分子分類，這為轉錄失調相關疾病中的 TF 功能的研究提供了架構。
This study reports that alanine repeat expansions in the HOXD13 TF, which cause hereditary synpolydactyly in humans, alter its phase separation capacity and its capacity to co-condense with transcriptional co-activators. HOXD13 repeat expansions perturb the composition of HOXD13-containing condensates in vitro and in vivo and alter the transcriptional program in a cell-specific manner in a mouse model of synpolydactyly. Disease-associated repeat expansions in other TFs (HOXA13, RUNX2, and TBP) were similarly found to alter their phase separation. These results suggest that unblending of transcriptional condensates may underlie human pathologies. The researchers present a molecular classification of TF IDRs, which provides a framework to dissect TF function in diseases associated with transcriptional dysregulation.
Distinct Processing of lncRNAs Contributes toNon-conserved Functions in Stem Cells
Protease Inhibitor Cocktail, mini-Tablet purchased from MCE.長的非編碼 RNA (lncRNA) 比 mRNA 進化得更快。保守的 lncRNA 是否進行保守的加工，其定位和功能仍待探索。該研究報道了人類和小鼠胚胎干細胞 (ESC) 中 lncRNAs 的不同亞細胞定位。與 mESCs 相比，在 hESCs 的細胞質中 lncRNA 的比例明顯更高，而這對于 hESC 的多能性很重要。FAST 是基因組位置保守的 lncRNA，但其加工和定位不保守。在 hESC 中，定位于細胞質的 hFAST 與 E3 泛素連接酶 β-TrCP 的 WD40 結構域結合，并阻斷其與磷酸化的 β-catenin 相互作用，以防止降解，從而激活多能性所需的 WNT 信號。相反，在 mESC 中 mFast 保留在細胞核，并且其加工受剪接因子 PPIE 抑制，PPIE 在 mESC 中高度表達，而在 hESC 中卻不然。這些發(fā)現(xiàn)表明，lncRNA 的加工和定位是功能快速進化中一直被低估的因素。
This study reports differing subcellular localization of lncRNAs in human and mouse embryonic stem cells (ESCs). A significantly higher fraction of lncRNAs is localized in the cytoplasm of hESCsthan in mESCs. This turns out to be important for hESC pluripotency. FAST is a positionally conserved lncRNA but is not conserved in its processing and localization. In hESCs, cytoplasm-localized hFAST binds to the WD40 domain of the E3 ubiquitin ligase β-TrCP and blocks its interaction with phosphorylated β-catenin to prevent degradation, leading to activated WNT signaling, required for pluripotency. In contrast, mFast is nuclear retained in mESCs, and its processing is suppressed by the splicing factor PPIE, which is highly expressed in mESCs but not hESCs. These findings reveal that lncRNA processing and localization are previously under-appreciated contributors to the rapid evolution of function.
Low-Dose Sorafenib Acts as a Mitochondrial Uncoupler and Ameliorates Nonalcoholic Steatohepatitis
Nigericin purchased from MCE.
非酒精性脂肪性肝炎 (NASH) 是肝細胞癌 (HCC) 的主要原因之一。盡管 Sorafenib 具有嚴重的不良反應，但卻是唯一的晚期肝癌一線治療藥物。該研究報道了大約相當于 HCC 臨床劑量十分之一的 Sorafenib，有效抑制了小鼠和猴子中 NASH 的進展，而未觀察到任何重大不良事件。在機制上，Sorafenib 在 NASH 中的作用與其在 HCC 中的典型激酶靶點無關，但涉及輕度線粒體解偶聯(lián)的誘導以及隨后 AMPK 的激活。總的來說，該研究結果證明了低劑量 Sorafenib 在 NASH 中的治療作用和信號傳導機制，而這點之前并未被重視。研究人員預想，這種新的 NASH 治療策略有潛力轉化為有益的抗 NASH 治療，并且與目前在 HCC 中使用的藥物相比，不良事件更少。
This study reports that at an equivalent of approximately one-tenth the clinical dose for HCC, sorafenib treatment effectively prevents the progression of NASH in both mice and monkeys without any observed significant adverse events. Mechanistically, sorafenib's benefit in NASH is independent of its canonical kinase targets in HCC, but involves the induction of mild mitochondrial uncoupling and subsequent activation of AMP-activated protein kinase (AMPK). Collectively, our findings demonstrate a previously unappreciated therapeutic effect and signaling mechanism of low-dose sorafenib treatment in NASH. The researchers envision that this new therapeutic strategy for NASH has the potential to translate into a beneficial anti-NASH therapy with fewer adverse events than is observed in the drug's current use in HCC.
Zonation of Ribosomal DNA Transcription Defines a Stem Cell Hierarchy in Colorectal Cancer
Y-27632 (dihydrochloride), AP20187 purchased from MCE.
結直腸癌 (CRCs) 由不同基因型和表型的細胞混合組成。該研究首次揭示了 CRC 細胞生物合成能力的異質性。研究人員發(fā)現(xiàn) CRCs 中的大部分核糖體 DNA 轉錄和蛋白質合成發(fā)生在特定的有限腫瘤細胞亞群中。其余的腫瘤細胞由于分化而發(fā)生了不可逆的生物合成能力喪失。生物合成區(qū)域內(nèi)的癌細胞的 RNA 聚合酶 I 亞基 A (POLR1A) 水平升高。POLR1A 高水平細胞群體的遺傳消融對 CRCs 造成不可逆的生長停滯。研究顯示，升高的生物合成決定了 LGR5+ 和 LGR5- 腫瘤細胞的干細胞特性。因此，CRCs 是基于轉錄核糖體 DNA 和合成蛋白質的差異能力的簡單的細胞層次結構。
The study reveals a previously unappreciated heterogeneity in the biosynthetic capacities of CRC cells. The researchers discovered that the majority of ribosomal DNA transcription and protein synthesis in CRCsoccurs in a limited subset of tumor cells that localize in defined niches. The rest of the tumor cells undergo an irreversible loss of their biosynthetic capacities as a consequence of differentiation. Cancer cells within the biosynthetic domains are characterized by elevated levels of the RNA polymerase I subunit A (POLR1A). Genetic ablation of POLR1A-high cell population imposes an irreversible growth arrest on CRCs. This research shows that elevated biosynthesis defines stemness in both LGR5+ and LGR5- tumor cells. Therefore, a common architecture in CRCs is a simple cell hierarchy based on the differential capacity to transcribe ribosomal DNA and synthesize proteins.
Seliciclib, THZ531, LDC000067 purchased from MCE.
分子膠化合物能誘導蛋白質-蛋白質相互作用，在存在泛素連接酶的情況下導致蛋白質降解。與傳統(tǒng)的酶抑制劑不同，這些分子膠降解劑在亞化學計量起催化作用，快速降解其靶標。在該研究中，研究人員通過系統(tǒng)地挖掘數(shù)據(jù)庫以研究 4,518 種臨床和臨床前小分子的細胞毒性與數(shù)百種人類癌細胞系中 E3 連接酶成分表達水平的相關性，鑒定了一種 CDK 抑制劑 CR8 作為分子膠降解劑。該研究表明，暴露在表面的部分的化學變化使抑制劑獲得分子膠功能，因此，研究人員認為這可以作為更廣泛的策略，將目標結合分子轉化為分子膠。
Through systematically mining databases for correlations between the cytotoxicity of 4,518 clinical and preclinical small molecules and the expression levels of E3 ligase components across hundreds of human cancer cell lines, the researchers identify CR8-a cyclin-dependent kinase (CDK) inhibitor-as a compound that acts as a molecular glue degrader. The CDK-bound form of CR8 has a solvent-exposed pyridyl moiety that induces the formation of a complex between CDK12-cyclin K and the CUL4 adaptor protein DDB1, by passing there requirement for a substrate receptor and presenting cyclin K for ubiquitination and degradation. Their studies demonstrate that chemical alteration of surface-exposed moieties can confer gain-of-function glue properties to an inhibitor, and they propose this as a broader strategy through which target-binding molecules could be converted into molecular glues.
Rapid Reconstruction of SARS-CoV-2 Using a Synthetic Genomics Platform (在線)
Remdesivir purchased from MCE.
反向遺傳學已經(jīng)成為一種必不可少的工具，徹底改變了我們對病毒發(fā)病機理和疫苗開發(fā)的認識。大型 RNA 病毒基因組，例如冠狀病毒，由于大小和不穩(wěn)定性，在大腸桿菌中難以克隆和操作。因此，開發(fā)一種快速和強大的 RNA 病毒反向遺傳學平臺有利于未來研究。該研究展示了一個基于酵母合成的基因組平臺，以用于不同的 RNA 病毒的基因重建，包括冠病毒科、黃病毒科和副粘病毒科。使用病毒分離物、克隆病毒 DNA、臨床樣本或合成的 DNA 生成病毒亞基因組片段，并使用轉化相關重組 (TAR）克隆將基因組維持為酵母人工染色體 (YAC)，以實現(xiàn)在釀酒酵母中重組。T7-RNA 聚合酶已被用于產(chǎn)生傳染性 RNA 以產(chǎn)生活病毒。基于這個平臺，在收到合成的 DNA 片段后僅一周內(nèi)，研究人員就能夠對的化學合成克隆進行工程改造和復活。這項技術進步能夠對新興的病毒做出快速反應，在病毒感染爆發(fā)期間對不斷發(fā)展的 RNA 病毒變體進行功能表征。This study shows the full functionality of a yeast-based synthetic genomics platform to genetically reconstruct diverse RNA viruses, including members of the Coronaviridae, Flaviviridae and Paramyxoviridae families. Viral subgenomic fragments were generated using viral isolates, cloned viral DNA, clinical samples, or synthetic DNA, and reassembled in one step in Saccharomyces cerevisiae using transformation associated recombination (TAR) cloning to maintain the genome as a yeast artificial chromosome (YAC). T7-RNA polymerase has been used to generate infectious RNA to rescue viable virus. Based on this platform we have been able to engineer and resurrect chemically-synthetized clones of the recent epidemic SARS-CoV-2 in only a week after receipt of the synthetic DNA fragments. The technical advance we describe here allows a rapidly response to emerging viruses as it enables the generation and functional characterization of evolving RNA virus variants-in real-time-during an outbreak.
Adaptive response to inflammation contributes to sustained myelopoiesis and confers a competitive advantage in myelodysplastic syndrome HSCs
NIK SMI1 purchased from MCE.
盡管有證據(jù)表明骨髓增生異常綜合癥 (MDS) 中存在慢性炎癥， MDS 造血干細胞和祖細胞 (HSPC) 中 Toll 樣受體 (TLR) 信號調節(jié)異常，但 MDS HSPC 在炎癥環(huán)境中比正常 HSPC 更具有競爭優(yōu)勢的機制尚不清楚。該研究發(fā)現(xiàn)，慢性炎癥是 MDS HSPC 競爭優(yōu)勢和疾病進展的決定因素。與正常 HSPC 相比，涉及通過非經(jīng)典 NF-κB 途徑信號傳導的 MDS HSPC 細胞內(nèi)源性反應，保護了這些細胞免于慢性炎癥。為了響應炎癥，MDS HSPC 由經(jīng)典的 NF-κB 信號轉為非經(jīng)典的 NF-κB 信號，這一過程依賴于 TLR-TRAF6 介導的 A20 激活。通過敲除 A20 或抑制非經(jīng)典 NF-κB 途徑，TLR-TRAF6 誘導的 HSPC 的競爭優(yōu)勢消失。這些發(fā)現(xiàn)揭示了 MDS HSPCs 克隆優(yōu)勢的機制基礎，并表明干擾非經(jīng)典 NF-κB 信號傳導可以抑制 MDS 的進展。
The research found that chronic inflammation was a determinant for the competitive advantage of MDS HSPCs and for disease progression. The cell-intrinsic response of MDS HSPCs, which involves signaling through the noncanonical NF-κB pathway, protected these cells from chronic inflammation as compared to normal HSPCs. In response to inflammation, MDS HSPCs switched from canonical to noncanonical NF-κB signaling, a process that was dependent on TLR-TRAF6-mediated activation of A20. The competitive advantage of TLR-TRAF6-primed HSPCs could be restored by deletion of A20 or inhibition of the noncanonical NF-κB pathway. These findings uncover the mechanistic basis for the clonal dominance of MDS HSPCs and indicate that interfering with noncanonical NF-κB signaling could prevent MDS progression.
Structural Basis for Inhibition of the RNA-dependent RNA Polymerase From SARS-CoV-2 by Remdesivir
Remdesivir purchased from MCE.
由 SARS-CoV-2 引起的 COVID-19 大流行已成為全球性危機。SARS-CoV-2 的復制需要病毒 RNA 依賴性的 RNA 聚合酶 (RdRp)，它是抗病毒藥物 Remdesivir 的靶標。該研究報道了 SARS-CoV-2 RdRp 的兩種冷凍電子顯微鏡結構: 2.8Å 的分辨率下呈 apo 形式 (apo form)，和 2.5Å 的分辨率下的 50 個堿基的模板引物 RNA 和 Remdesivir 形成的復合體。復雜的結構揭示了部分雙鏈 RNA 模板插入了 RdRp 的中心通道，Remdesivir 在第一個復制的堿基對處共價摻入引物鏈，并終止了鏈延長。該研究為抗病毒感染的藥物研發(fā)提供了重要的理論機制和結構基礎。
This study reports the cryo-EM structure of the SARS-CoV-2 RdRp either in the apo format 2.8 Å resolution or in complex with a 50-base template-primer RNA and Remdesivir at 2.5 Å resolution. The complex structure reveals that the partial double-stranded RNA template is inserted into the central channel of the RdRp where Remdesivir is covalently incorporated into the primer strand at the first replicated base pair and terminates chain elongation. Our structures provide critical insights into the mechanism of viral RNA replication and a rational template for drug design to combat the viral infection.
