HR, homologous recombination

HR,同源重组
  • 文章类型: Journal Article
    The cell as a system of many components, governed by the laws of physics and chemistry drives molecular functions having an impact on the spatial organization of these systems and vice versa. Since the relationship between structure and function is an almost universal rule not only in biology, appropriate methods are required to parameterize the relationship between the structure and function of biomolecules and their networks, the mechanisms of the processes in which they are involved, and the mechanisms of regulation of these processes. Single molecule localization microscopy (SMLM), which we focus on here, offers a significant advantage for the quantitative parametrization of molecular organization: it provides matrices of coordinates of fluorescently labeled biomolecules that can be directly subjected to advanced mathematical analytical procedures without the need for laborious and sometimes misleading image processing. Here, we propose mathematical tools for comprehensive quantitative computer data analysis of SMLM point patterns that include Ripley distance frequency analysis, persistent homology analysis, persistent \'imaging\', principal component analysis and co-localization analysis. The application of these methods is explained using artificial datasets simulating different, potentially possible and interpretatively important situations. Illustrative analyses of real complex biological SMLM data are presented to emphasize the applicability of the proposed algorithms. This manuscript demonstrated the extraction of features and parameters quantifying the influence of chromatin (re)organization on genome function, offering a novel approach to study chromatin architecture at the nanoscale. However, the ability to adapt the proposed algorithms to analyze essentially any molecular organizations, e.g., membrane receptors or protein trafficking in the cytosol, offers broad flexibility of use.
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  • 文章类型: Journal Article
    未经证实:间充质基质细胞(MSCs)具有作为细胞治疗产品应用的潜力;然而,在临床使用之前,有许多问题需要解决,这些包括MSC的异质性,MSC生产中的可扩展性,MSC管理的时机和技术,以及施用的MSC的植入效率和持久性。在这项研究中,解决了由人类白细胞抗原(HLA)错配引起的免疫排斥问题。
    未授权:对脐带来源的MSCs(UC-MSCs)进行基因编辑以避免同种异体免疫。通过敲除β-2-微球蛋白(B2M)基因来消除HLAI类表达;相反,使用CRISPR/Cas9系统联合腺相关病毒(AAV)敲入B2M-HLA-G融合基因.
    未经鉴定:基因编辑的UC-MSCs上的细胞表面标记与原代UC-MSCs上的标记没有差异。基因编辑的UC-MSCs还保留了分化为脂肪细胞的潜力,成骨细胞,和软骨细胞.B2M基因敲除单独保护细胞免受同种异体T细胞免疫应答,但对NK细胞易感。B2M基因敲除与B2M-HLA-G敲入组合保护细胞免受T细胞和NK细胞两者的侵害。B2M-HLA-G敲入MSC保留了良好的免疫抑制能力,并且将这些细胞添加到混合淋巴细胞反应中显示出对T细胞增殖的显着抑制。
    UNASSIGNED:这项研究的结果表明,与AAV结合的CRISPR/Cas9系统可用于有效破坏/将任何基因引入UC-MSC的可能性。我们的发现表明,使用这种方法产生的基因编辑细胞系可能比原代细胞具有更高的逃避免疫细胞细胞毒活性的能力,从而更有利于移植物的长期存活。
    UNASSIGNED: Mesenchymal stromal cells (MSCs) hold the potential for application as cellular therapy products; however, there are many problems that need to be addressed before the use in clinical settings, these include the heterogeneity of MSCs, scalability in MSC production, timing and techniques for MSC administration, and engraftment efficiency and persistency of administered MSCs. In this study, problems regarding immune rejection caused by human leukocyte antigen (HLA) mismatches were addressed.
    UNASSIGNED: Umbilical cord-derived MSCs (UC-MSCs) were gene-edited to avoid allogeneic immunity. The HLA class I expression was abrogated by the knock-out of the beta-2-microglobulin (B2M) gene; instead, the B2M-HLA-G fusion gene was knocked-in using the CRISPR/Cas9 system in combination with adeno-associated virus (AAV).
    UNASSIGNED: Cell surface markers on gene-edited UC-MSCs were not different from those on primary UC-MSCs. The gene-edited UC-MSCs also retained the potential to differentiate into adipocytes, osteoblasts, and chondrocytes. B2M gene knock-out alone protected cells from allogeneic T cell immune responses but were vulnerable to NK cells. B2M gene knock-out in combination with B2M-HLA-G knock-in protected cells from both T cells and NK cells. The B2M-HLA-G knock-in MSCs retained a good immunosuppressive ability and the addition of these cells into the mixing lymphocyte reaction showed a significant inhibition of T cell proliferation.
    UNASSIGNED: The results of this study demonstrated the possibility that the CRISPR/Cas9 system combined with AAV can be used to effectively disrupt/introduce any gene into UC-MSCs. Our findings suggest that the gene-edited cell line produced here using this method may have a higher ability to escape the cytotoxic activity of immune cells than primary cells, thereby being more advantageous for long-term graft survival.
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  • 文章类型: Journal Article
    基因和通路大小的DNA盒的基因组整合通常是构建强大和高效的微生物细胞工厂的不可或缺的方式。对于一些不常见的微生物宿主,如分枝杆菌和分枝杆菌,然而,这是一个挑战。这里,我们提出了一种多重整合酶辅助位点特异性重组(miSSR)方法,以精确和迭代地将具有可控拷贝的基因/途径整合到分枝杆菌染色体中,以开发细胞工厂。首先,通过结合应用分枝杆菌噬菌体L5整合酶和两步等位基因交换策略,在新牛分枝杆菌中建立了一步多拷贝整合方法,对于不超过三拷贝整合事件,其效率为100%,对于五拷贝整合事件,其效率急剧下降至20%。第二,选择R4,Bxb1和ΦC31噬菌体Att/Int系统,以扩展用于多重基因整合事件的可用整合工具箱.第三,使用重建的霉菌Xer重组酶(Xer-cise)系统回收基因重组的选择标记,以促进迭代基因操作。作为概念的证明,新分枝杆菌ATCC25795中麦角硫因(EGT)的生物合成途径是通过用miSSR系统重塑其代谢途径来实现的。EGT和磷酸戊糖异构酶(PRT)的生物合成基因簇(BGC)的六个拷贝,在30mL摇瓶中,5天内所得菌株的EGT滴度提高到66mg/L,是野生菌株的3.77倍。改进表明,miSSR系统是一种有效的,灵活,和方便的工具来设计分枝杆菌以及分枝杆菌科中其他菌株的基因组,因为它们之间的近邻进化关系。
    Genomic integration of genes and pathway-sized DNA cassettes is often an indispensable way to construct robust and productive microbial cell factories. For some uncommon microbial hosts, such as Mycolicibacterium and Mycobacterium species, however, it is a challenge. Here, we present a multiplexed integrase-assisted site-specific recombination (miSSR) method to precisely and iteratively integrate genes/pathways with controllable copies in the chromosomes of Mycolicibacteria for the purpose of developing cell factories. First, a single-step multi-copy integration method was established in M. neoaurum by a combination application of mycobacteriophage L5 integrase and two-step allelic exchange strategy, the efficiencies of which were ∼100% for no more than three-copy integration events and decreased sharply to ∼20% for five-copy integration events. Second, the R4, Bxb1 and ΦC31 bacteriophage Att/Int systems were selected to extend the available integration toolbox for multiplexed gene integration events. Third, a reconstructed mycolicibacterial Xer recombinases (Xer-cise) system was employed to recycle the selection marker of gene recombination to facilitate the iterative gene manipulation. As a proof of concept, the biosynthetic pathway of ergothioneine (EGT) in Mycolicibacterium neoaurum ATCC 25795 was achieved by remodeling its metabolic pathway with a miSSR system. With six copies of the biosynthetic gene clusters (BGCs) of EGT and pentose phosphate isomerase (PRT), the titer of EGT in the resulting strain in a 30 mL shake flask within 5 days was enhanced to 66 mg/L, which was 3.77 times of that in the wild strain. The improvements indicated that the miSSR system was an effective, flexible, and convenient tool to engineer the genomes of Mycolicibacteria as well as other strains in the Mycobacteriaceae due to their proximate evolutionary relationships.
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  • 文章类型: Journal Article
    卵巢癌是全球女性中第8种最致命的常见癌症。几乎所有的卵巢癌患者都会经历化疗耐药,复发,细胞减灭术和铂类化疗后预后不良。化疗耐药的癌细胞具有肿瘤干细胞蛋白(CSCs)CD44+/CD24-的特征性表达,RAD6和DDB2。CD44+/CD24-的表达增加,RAD6和DDB2的降低被认为与化学抗性有关,复发,和疾病的不良预后。因此,本研究的目的是分析CD44+/CD24-,RAD6和DDB2与卵巢癌化疗耐药。
    这项研究是在CiptoMangunkusumo妇产科和病理科进行的64名患者的前瞻性队列研究,分为两组(每组32名患者),Tarakan,Dharmais,和Fatmawati医院.所有疑似卵巢癌患者均接受了细胞减灭术和组织病理学检查。进行了六个系列的化疗,然后进行了六个月的观察。在观察之后,我们使用RECIST标准(实体瘤的反应标准)确定治疗的反应,然后将结果分为化学耐药组或化学敏感组.然后进行流式细胞术血液测试以检查CD44/CD24-的表达,RAD6和DDB2。
    CD44+/CD24-,和RAD6(p<0.05)水平与卵巢癌化疗耐药有关。Logistic回归检验显示CD44+/CD24-是较好的标记物。
    这些结果表明CD44+/CD24和RAD6的表达与卵巢癌化疗耐药显著相关,CD44+/CD24-是预测卵巢癌化疗耐药的较好指标。
    UNASSIGNED: Ovarian cancer is the 8th deadliest common cancer in women around the world. Almost all ovarian cancer patients would experience chemoresistance, recurrence, and poor prognosis after cytoreductive surgery and platinum-based chemotherapy. Chemoresistant cancer cells have characteristic expressions of cancer stem cell proteins (CSCs) CD44+/CD24-, RAD6 and DDB2. The increased expression of CD44+/CD24-, RAD6, and decreased DDB2 are believed to be associated with chemoresistance, recurrence, and poor prognosis of the disease. Thus, this study\'s objective is to analyze the correlation between the expression of CD44+/CD24-, RAD6 and DDB2 with ovarian cancer chemoresistance.
    UNASSIGNED: This study was conducted with a prospective cohort of 64 patients who is divided into two groups (32 patients in each group) at the Obstetrics-gynecology and pathology department of Cipto Mangunkusumo, Tarakan, Dharmais, and Fatmawati Hospital. All suspected ovarian cancer patients underwent cytoreductive debulking and histopathological examination. Chemotherapy was given for six series followed by six months of observation. After the observation, we determined the therapy\'s response with the RECIST Criteria (Response Criteria in Solid Tumors) and then classified the results into chemoresistant or chemosensitive groups. Flow cytometry blood tests were then performed to examine the expression of CD44+/CD24-, RAD6 and DDB2.
    UNASSIGNED: There was a significant relationship between increased levels of CD44+/CD24-, and RAD6 (p < 0.05) levels with the chemoresistance of ovarian cancer. The logistic regression test showed that the CD44+/CD24- was better marker.
    UNASSIGNED: These results indicate that CD44+/CD24 and RAD6 expressions are significantly associated with ovarian cancer chemoresistance, and CD44+/CD24- is the better marker to predict ovarian cancer chemoresistance.
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  • 文章类型: Journal Article
    各种心肌病的主要病因现在被认为是遗传的,在潜在分子原因的基础上创造一种新的靶向治疗模式。这篇综述为心肌病的传统临床分类提供了遗传和病因学背景,包括可能对现有或新兴治疗表现出不同反应的分子亚型。作者描述了几种新兴的心肌病治疗方法,包括基因疗法,直接靶向肌丝功能,蛋白质质量控制,新陈代谢,和其他人。作者讨论了这些方法的优缺点,并指出了短期和长期疗效的高潜力领域。
    The primary etiology of a diverse range of cardiomyopathies is now understood to be genetic, creating a new paradigm for targeting treatments on the basis of the underlying molecular cause. This review provides a genetic and etiologic context for the traditional clinical classifications of cardiomyopathy, including molecular subtypes that may exhibit differential responses to existing or emerging treatments. The authors describe several emerging cardiomyopathy treatments, including gene therapy, direct targeting of myofilament function, protein quality control, metabolism, and others. The authors discuss advantages and disadvantages of these approaches and indicate areas of high potential for short- and longer term efficacy.
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  • 文章类型: Journal Article
    显著比例的非小细胞肺癌(NSCLC)患者经历累积的化疗相关不良事件,激励化学增敏策略的设计。化学治疗剂诱导的主要细胞毒性损伤是DNA双链断裂(DSB)。因此可以想象,减弱DNA修复的DNA依赖性蛋白激酶(DNA-PK)抑制剂将增强化疗的抗肿瘤作用。本研究旨在系统评估新型DNA-PK抑制剂M3814与化疗对NSCLC的协同作用的疗效和安全性。我们确定了DNA-PK在人NSCLC组织中的表达增加,这与不良预后有关。M3814增强了紫杉醇和依托泊苷在A549、H460和H1703NSCLC细胞系中的抗肿瘤作用。在基于两种NSCLC异种移植模型和两种化疗的四种组合中,我们还在体内观察到耐受剂量的肿瘤消退。此外,我们发现,紫杉醇/依托泊苷治疗后,M3814出现了P53依赖性的加速衰老反应.本研究为M3814联合紫杉醇和依托泊苷在临床上的应用提供了理论依据。希望有助于优化NSCLC治疗。
    A significant proportion of non-small cell lung cancer (NSCLC) patients experience accumulating chemotherapy-related adverse events, motivating the design of chemosensitizating strategies. The main cytotoxic damage induced by chemotherapeutic agents is DNA double-strand breaks (DSB). It is thus conceivable that DNA-dependent protein kinase (DNA-PK) inhibitors which attenuate DNA repair would enhance the anti-tumor effect of chemotherapy. The present study aims to systematically evaluate the efficacy and safety of a novel DNA-PK inhibitor M3814 in synergy with chemotherapies on NSCLC. We identified increased expression of DNA-PK in human NSCLC tissues which was associated with poor prognosis. M3814 potentiated the anti-tumor effect of paclitaxel and etoposide in A549, H460 and H1703 NSCLC cell lines. In the four combinations based on two NSCLC xenograft models and two chemotherapy, we also observed tumor regression at tolerated doses in vivo. Moreover, we identified a P53-dependent accelerated senescence response by M3814 following treatment with paclitaxel/etoposide. The present study provides a theoretical basis for the use of M3814 in combination with paclitaxel and etoposide in clinical practice, with hope to aid the optimization of NSCLC treatment.
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  • 文章类型: Journal Article
    A major mitochondrial enzyme for protecting cells from acetaldehyde toxicity is aldehyde dehydrogenase 2 (ALDH2). The correlation between ALDH2 dysfunction and tumorigenesis/growth/metastasis has been widely reported. Either low or high ALDH2 expression contributes to tumor progression and varies among different tumor types. Furthermore, the ALDH2∗2 polymorphism (rs671) is the most common single nucleotide polymorphism (SNP) in Asia. Epidemiological studies associate ALDH2∗2 with tumorigenesis and progression. This study summarizes the essential functions and potential ALDH2 mechanisms in the occurrence, progression, and treatment of tumors in various types of cancer. Our study indicates that ALDH2 is a potential therapeutic target for cancer therapy.
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  • 文章类型: Journal Article
    需要开发第三代生物精炼厂,其将能量生产与从可再生原料生产更高价值的化学品相结合。这里,酿酒酵母的健壮和耐受胁迫的工业菌株将是合适的生产生物。然而,他们的基因操纵具有挑战性,因为它们通常是二倍体或多倍体。因此,有必要开发更有效的基因工程工具。我们应用CRISPR-Cas9系统对不同的工业菌株进行基因组编辑,并在几个不相关的菌株中同时破坏了一个基因的两个等位基因,效率在65%至78%之间。我们还实现了报告基因的同时破坏和敲入,并通过在单个转化事件中设计产乳酸菌株来证明该方法的适用性,异源基因的插入和两个内源基因的破坏同时发生。我们的研究为工业酵母细胞工厂的有效工程提供了基础。
    There is a demand to develop 3rd generation biorefineries that integrate energy production with the production of higher value chemicals from renewable feedstocks. Here, robust and stress-tolerant industrial strains of Saccharomyces cerevisiae will be suitable production organisms. However, their genetic manipulation is challenging, as they are usually diploid or polyploid. Therefore, there is a need to develop more efficient genetic engineering tools. We applied a CRISPR-Cas9 system for genome editing of different industrial strains, and show simultaneous disruption of two alleles of a gene in several unrelated strains with the efficiency ranging between 65% and 78%. We also achieved simultaneous disruption and knock-in of a reporter gene, and demonstrate the applicability of the method by designing lactic acid-producing strains in a single transformation event, where insertion of a heterologous gene and disruption of two endogenous genes occurred simultaneously. Our study provides a foundation for efficient engineering of industrial yeast cell factories.
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  • 文章类型: Journal Article
    This study was aimed to design the first dual-target small-molecule inhibitor co-targeting poly (ADP-ribose) polymerase-1 (PARP1) and bromodomain containing protein 4 (BRD4), which had important cross relation in the global network of breast cancer, reflecting the synthetic lethal effect. A series of new BRD4 and PARP1 dual-target inhibitors were discovered and synthesized by fragment-based combinatorial screening and activity assays that together led to the chemical optimization. Among these compounds, 19d was selected and exhibited micromole enzymatic potencies against BRD4 and PARP1, respectively. Compound 19d was further shown to efficiently modulate the expression of BRD4 and PARP1. Subsequently, compound 19d was found to induce breast cancer cell apoptosis and stimulate cell cycle arrest at G1 phase. Following pharmacokinetic studies, compound 19d showed its antitumor activity in breast cancer susceptibility gene 1/2 (BRCA1/2) wild-type MDA-MB-468 and MCF-7 xenograft models without apparent toxicity and loss of body weight. These results together demonstrated that a highly potent dual-targeted inhibitor was successfully synthesized and indicated that co-targeting of BRD4 and PARP1 based on the concept of synthetic lethality would be a promising therapeutic strategy for breast cancer.
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  • 文章类型: Journal Article
    热纤梭菌的强大的木质纤维素增溶活性使其成为用于生物燃料生产的综合生物加工的首选。热纤梭菌的遗传技术落后于模型生物,因此限制了改善生物燃料生产的尝试。为了提高我们设计C.热纤的能力,我们表征了天然I-B型和异源II型聚集定期间隔短回文重复(CRISPR)/cas(CRISPR相关)系统。我们将天然I-B型系统重新用于基因组编辑。我们测试了三种嗜热Cas9变体(II型),发现从嗜热脂肪地芽孢杆菌中分离出的GeoCas9,在C.热纤中活跃。我们采用CRISPR介导的同源定向修复将无义突变引入pyrF。对于两种编辑系统,修复模板和基因组之间的同源重组似乎是限制步骤。为了克服这个限制,我们测试了三种新的嗜热重组酶,并证明了exo/beta同源物,从caldus酸硫杆菌中分离出来,在C.热纤细胞中有功能。对于I-B型系统,工程菌株,称为LL1586,在pyrF基因座处产生40%的基因组编辑效率,并且当重组机制表达时,这增加到71%。对于II型GeoCas9系统,观察到12.5%的基因组编辑效率,当重组机制表达时,增加到94%。通过将嗜热CRISPR系统(I-B型或II型)与重组酶结合,我们开发了一种新工具,可以进行高效的CRISPR编辑。我们现在准备使CRISPR技术能够更好地设计C.热纤纤维,以增加木质纤维素的降解和生物燃料的生产。
    The robust lignocellulose-solubilizing activity of C. thermocellum makes it a top candidate for consolidated bioprocessing for biofuel production. Genetic techniques for C. thermocellum have lagged behind model organisms thus limiting attempts to improve biofuel production. To improve our ability to engineer C. thermocellum, we characterized a native Type I-B and heterologous Type II Clustered Regularly-Interspaced Short Palindromic Repeat (CRISPR)/cas (CRISPR associated) systems. We repurposed the native Type I-B system for genome editing. We tested three thermophilic Cas9 variants (Type II) and found that GeoCas9, isolated from Geobacillus stearothermophilus, is active in C. thermocellum. We employed CRISPR-mediated homology directed repair to introduce a nonsense mutation into pyrF. For both editing systems, homologous recombination between the repair template and the genome appeared to be the limiting step. To overcome this limitation, we tested three novel thermophilic recombinases and demonstrated that exo/beta homologs, isolated from Acidithiobacillus caldus, are functional in C. thermocellum. For the Type I-B system an engineered strain, termed LL1586, yielded 40% genome editing efficiency at the pyrF locus and when recombineering machinery was expressed this increased to 71%. For the Type II GeoCas9 system, 12.5% genome editing efficiency was observed and when recombineering machinery was expressed, this increased to 94%. By combining the thermophilic CRISPR system (either Type I-B or Type II) with the recombinases, we developed a new tool that allows for efficient CRISPR editing. We are now poised to enable CRISPR technologies to better engineer C. thermocellum for both increased lignocellulose degradation and biofuel production.
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