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Transposable elements as essential elements in the control of gene expression. 转座因子是调控基因表达的重要因子。
IF 4.7 2区 生物学 Q1 GENETICS & HEREDITY Pub Date : 2023-08-18 DOI: 10.1186/s13100-023-00297-3
Alemu Gebrie

Interspersed repetitions called transposable elements (TEs), commonly referred to as mobile elements, make up a significant portion of the genomes of higher animals. TEs contribute in controlling the expression of genes locally and even far away at the transcriptional and post-transcriptional levels, which is one of their significant functional effects on gene function and genome evolution. There are different mechanisms through which TEs control the expression of genes. First, TEs offer cis-regulatory regions in the genome with their inherent regulatory features for their own expression, making them potential factors for controlling the expression of the host genes. Promoter and enhancer elements contain cis-regulatory sites generated from TE, which function as binding sites for a variety of trans-acting factors. Second, a significant portion of miRNAs and long non-coding RNAs (lncRNAs) have been shown to have TEs that encode for regulatory RNAs, revealing the TE origin of these RNAs. Furthermore, it was shown that TE sequences are essential for these RNAs' regulatory actions, which include binding to the target mRNA. By being a member of cis-regulatory and regulatory RNA sequences, TEs therefore play essential regulatory roles. Additionally, it has been suggested that TE-derived regulatory RNAs and cis-regulatory regions both contribute to the evolutionary novelty of gene regulation. Additionally, these regulatory systems arising from TE frequently have tissue-specific functions. The objective of this review is to discuss TE-mediated gene regulation, with a particular emphasis on the processes, contributions of various TE types, differential roles of various tissue types, based mostly on recent studies on humans.

被称为转座因子(te)的分散重复,通常被称为可移动因子,构成了高等动物基因组的重要部分。te在转录和转录后水平上参与调控基因的局部甚至远端表达,这是其对基因功能和基因组进化的重要功能作用之一。TEs通过不同的机制控制基因的表达。首先,te在基因组中提供了对自身表达具有内在调控特性的顺式调控区域,使其成为控制宿主基因表达的潜在因子。启动子和增强子元件包含由TE产生的顺式调控位点,这些位点作为多种反式作用因子的结合位点。其次,相当一部分mirna和长链非编码rna (lncrna)已被证明具有编码调控rna的TE,揭示了这些rna的TE起源。此外,研究表明TE序列对这些rna的调控作用至关重要,包括与目标mRNA的结合。作为顺式调控RNA和调节性RNA序列的成员,te因此发挥了重要的调控作用。此外,有研究表明te衍生的调控rna和顺式调控区域都有助于基因调控的进化新颖性。此外,这些由TE引起的调节系统通常具有组织特异性功能。这篇综述的目的是讨论TE介导的基因调控,特别强调的过程,各种TE类型的贡献,不同组织类型的差异作用,主要基于最近对人类的研究。
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引用次数: 0
Reproducible evaluation of transposable element detectors with McClintock 2 guides accurate inference of Ty insertion patterns in yeast. 用McClintock 2对转座元件检测器的可重复性评价指导了酵母中Ty插入模式的准确推断。
IF 4.9 2区 生物学 Q1 GENETICS & HEREDITY Pub Date : 2023-07-14 DOI: 10.1186/s13100-023-00296-4
Jingxuan Chen, Preston J Basting, Shunhua Han, David J Garfinkel, Casey M Bergman

Background: Many computational methods have been developed to detect non-reference transposable element (TE) insertions using short-read whole genome sequencing data. The diversity and complexity of such methods often present challenges to new users seeking to reproducibly install, execute, or evaluate multiple TE insertion detectors.

Results: We previously developed the McClintock meta-pipeline to facilitate the installation, execution, and evaluation of six first-generation short-read TE detectors. Here, we report a completely re-implemented version of McClintock written in Python using Snakemake and Conda that improves its installation, error handling, speed, stability, and extensibility. McClintock 2 now includes 12 short-read TE detectors, auxiliary pre-processing and analysis modules, interactive HTML reports, and a simulation framework to reproducibly evaluate the accuracy of component TE detectors. When applied to the model microbial eukaryote Saccharomyces cerevisiae, we find substantial variation in the ability of McClintock 2 components to identify the precise locations of non-reference TE insertions, with RelocaTE2 showing the highest recall and precision in simulated data. We find that RelocaTE2, TEMP, TEMP2 and TEBreak provide consistent estimates of [Formula: see text]50 non-reference TE insertions per strain and that Ty2 has the highest number of non-reference TE insertions in a species-wide panel of [Formula: see text]1000 yeast genomes. Finally, we show that best-in-class predictors for yeast applied to resequencing data have sufficient resolution to reveal a dyad pattern of integration in nucleosome-bound regions upstream of yeast tRNA genes for Ty1, Ty2, and Ty4, allowing us to extend knowledge about fine-scale target preferences revealed previously for experimentally-induced Ty1 insertions to spontaneous insertions for other copia-superfamily retrotransposons in yeast.

Conclusion: McClintock ( https://github.com/bergmanlab/mcclintock/ ) provides a user-friendly pipeline for the identification of TEs in short-read WGS data using multiple TE detectors, which should benefit researchers studying TE insertion variation in a wide range of different organisms. Application of the improved McClintock system to simulated and empirical yeast genome data reveals best-in-class methods and novel biological insights for one of the most widely-studied model eukaryotes and provides a paradigm for evaluating and selecting non-reference TE detectors in other species.

背景:许多计算方法已经开发出来检测非参考转座元件(TE)插入使用短读全基因组测序数据。这种方法的多样性和复杂性通常给寻求可重复安装、执行或评估多个TE插入检测器的新用户带来挑战。结果:我们之前开发了McClintock元管道,以促进6个第一代短读TE检测器的安装、执行和评估。在这里,我们报告了一个使用Snakemake和Conda用Python编写的完全重新实现的McClintock版本,该版本改进了其安装、错误处理、速度、稳定性和可扩展性。McClintock 2现在包括12个短读TE检测器,辅助预处理和分析模块,交互式HTML报告和模拟框架,可重复评估组件TE检测器的准确性。当应用于模型真核微生物酿酒酵母时,我们发现McClintock 2组分识别非参考TE插入的精确位置的能力存在很大差异,其中RelocaTE2在模拟数据中显示出最高的召回率和精度。我们发现,RelocaTE2、TEMP、TEMP2和TEBreak提供了每个菌株50个非参考TE插入的一致估计,并且在1000个酵母基因组的物种范围内,Ty2的非参考TE插入数量最多。最后,我们发现,应用于酵母重测序数据的最佳预测因子具有足够的分辨率,可以揭示酵母tRNA基因上游核小体结合区域中Ty1、Ty2和Ty4的二联体整合模式,从而使我们能够将之前揭示的实验诱导的Ty1插入的精细靶标偏好扩展到酵母中其他复制超家族逆转录转座子的自发插入。结论:McClintock (https://github.com/bergmanlab/mcclintock/)提供了一个用户友好的管道,用于使用多个TE检测器识别短读WGS数据中的TE,这将有利于研究不同生物中TE插入变化的研究人员。将改进的McClintock系统应用于模拟和经验酵母基因组数据,为研究最广泛的模型真核生物之一提供了一流的方法和新的生物学见解,并为评估和选择其他物种的非参考TE检测器提供了范例。
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引用次数: 1
Host range of strand-biased circularizing integrative elements: a new class of mobile DNA elements nesting in Gammaproteobacteria. 偏链循环整合元件的宿主范围:一类新的移动DNA元件在γ变形菌中嵌套。
IF 4.9 2区 生物学 Q1 GENETICS & HEREDITY Pub Date : 2023-05-26 DOI: 10.1186/s13100-023-00295-5
Desmila Idola, Hiroshi Mori, Yuji Nagata, Lisa Nonaka, Hirokazu Yano

Background: The strand-biased circularizing integrative elements (SEs) are putatively non-mobilizable integrative elements for transmitting antimicrobial resistance genes. The transposition mode and the prevalence of SEs in prokaryotes remain vague.

Results: To corroborate the transposition mode and the prevalence of SEs, hypothetical transposition intermediates of an SE were searched for in genomic DNA fractions of an SE host. Then, the SE core genes were defined based on gene knockout experiments, and the synteny blocks of their distant homologs were searched for in the RefSeq complete genome sequence database using PSI-BLAST. A genomic DNA fractionation experiment revealed that SE copies are present in a double-stranded nicked circular form in vivo. Operonic structure of three conserved coding sequences (intA, tfp, intB) and srap located at the left end of SEs were identified as essential for attL × attR recombination. The synteny blocks of tfp and srap homologs were detected in 3.6% of the replicons of Gammaproteobacteria but not in other taxa, implying that SE movement is host-dependent. SEs have been discovered most frequently in the orders Vibrionales (19% of replicons), Pseudomonadales (18%), Alteromonadales (17%), and Aeromonadales (12%). Genomic comparisons revealed 35 new SE members with identifiable termini. SEs are present at 1 to 2 copies per replicon and have a median length of 15.7 kb. Three newly identified SE members carry antimicrobial resistance genes, like tmexCD-toprJ, mcr-9, and blaGMA-1. Further experiments validated that three new SE members possess the strand-biased attL × attR recombination activity.

Conclusions: This study suggested that transposition intermediates of SEs are double-stranded circular DNA. The main hosts of SEs are a subset of free-living Gammaproteobacteria; this represents a rather narrow host range compared to those of mobile DNA element groups discovered to date. As the host range, genetic organization, and movements are unique among the mobile DNA elements, SEs provide a new model system for host-mobile DNA element coevolution studies.

背景:偏链环状整合元件(SEs)被认为是不可移动的整合元件,用于传递抗菌素耐药基因。SEs在原核生物中的转位方式和流行程度尚不清楚。结果:为了证实SE的转位模式和流行程度,我们在SE宿主的基因组DNA片段中寻找了假设的SE转位中间体。然后,通过基因敲除实验确定SE核心基因,并使用PSI-BLAST在RefSeq全基因组序列数据库中搜索其远端同源物的synblock。基因组DNA分离实验显示,SE拷贝在体内以双链缺口圆形形式存在。鉴定出位于se左端的三个保守编码序列(intA、tfp、intB)和srap的操纵子结构是attL × attR重组所必需的。在Gammaproteobacteria的3.6%的复制子中检测到tfp和srap同源物的synsynblock,而在其他类群中没有,这表明SE的运动依赖于宿主。se最常见于弧菌目(占复制子的19%)、假单胞菌目(18%)、异单胞菌目(17%)和气单胞菌目(12%)。基因组比较发现35个新的SE成员具有可识别的末端。每个复制子有1到2个拷贝,中位长度为15.7 kb。三个新发现的SE成员携带抗菌耐药基因,如tmexd - toprj、mcr-9和blaGMA-1。进一步的实验验证了三个新的SE成员具有偏向链的attL × attR重组活性。结论:本研究提示SEs的转位中间体为双链环状DNA。se的主要宿主是自由生活的γ变形菌的一个子集;与迄今为止发现的可移动DNA元件群相比,这代表了一个相当狭窄的宿主范围。由于宿主范围、遗传组织和运动在移动DNA元件中具有独特性,因此为宿主-移动DNA元件协同进化研究提供了一个新的模型系统。
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引用次数: 1
THE1B may have no role in human pregnancy due to ZNF430-mediated silencing. 由于znf430介导的沉默,THE1B可能在人类妊娠中没有作用。
IF 4.9 2区 生物学 Q1 GENETICS & HEREDITY Pub Date : 2023-05-22 DOI: 10.1186/s13100-023-00294-6
Zheng Zuo

THE1-family retrovirus invaded the primate genome more than 40 million years ago. Dunn-Fletcher et al. reported one THE1B element upstream of CRH gene alters gestation length by upregulating corticotropin-releasing hormone expression in transgenic mice and concluded it has the same role in human as well. However, no promoter or enhancer mark has been detected around this CRH-proximal element in any human tissue or cell, so probably some anti-viral factor exists in primates to prevents it from wreaking havoc. Here I report two paralogous zinc finger genes, ZNF430 and ZNF100, that emerged during the simian lineage to specifically silence THE1B and THE1A, respectively. Contact residue changes in one finger confers each ZNF the unique ability to preferentially repress one THE1 sub-family over the other. The reported THE1B element contains an intact ZNF430 binding site, thus under the repression of ZNF430 in most tissues including placenta, it is questionable whether or not this retrovirus has any role in human pregnancy. Overall, this analysis highlights the need to study human retroviruses' functions in suitable model system.

1家族逆转录病毒在4000多万年前侵入灵长类基因组。Dunn-Fletcher等报道了CRH基因上游的一个THE1B元件在转基因小鼠中通过上调促肾上腺皮质激素释放激素的表达来改变妊娠期长度,并得出其在人类中也具有相同作用的结论。然而,在任何人类组织或细胞中,没有在crh -近端元件周围检测到启动子或增强子标记,因此可能在灵长类动物中存在一些抗病毒因子来阻止它造成破坏。在这里,我报道了两个相似的锌指基因,ZNF430和ZNF100,它们分别出现在类人猿谱系中,特异性地沉默了THE1B和THE1A。一个手指的接触残留变化赋予每个ZNF优先抑制一个THE1亚家族的独特能力。报道的THE1B元件含有一个完整的ZNF430结合位点,因此在包括胎盘在内的大多数组织中,在ZNF430的抑制下,这种逆转录病毒是否在人类妊娠中有任何作用是值得怀疑的。总之,这一分析强调了在合适的模型系统中研究人类逆转录病毒功能的必要性。
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引用次数: 1
Expression of L1 retrotransposons in granulocytes from patients with active systemic lupus erythematosus. 活动性系统性红斑狼疮患者粒细胞中L1反转录转座子的表达。
IF 4.9 2区 生物学 Q1 GENETICS & HEREDITY Pub Date : 2023-05-10 DOI: 10.1186/s13100-023-00293-7
Kennedy C Ukadike, Rayan Najjar, Kathryn Ni, Amanda Laine, Xiaoxing Wang, Alison Bays, Martin S Taylor, John LaCava, Tomas Mustelin

Background: Patients with systemic lupus erythematosus (SLE) have autoantibodies against the L1-encoded open-reading frame 1 protein (ORF1p). Here, we report (i) which immune cells ORF1p emanates from, (ii) which L1 loci are transcriptionally active, (iii) whether the cells express L1-dependent interferon and interferon-stimulated genes, and (iv) the effect of inhibition of L1 ORF2p by reverse transcriptase inhibitors.

Results: L1 ORF1p was detected by flow cytometry primarily in SLE CD66b+CD15+ regular and low-density granulocytes, but much less in other immune cell lineages. The amount of ORF1p was higher in neutrophils from patients with SLE disease activity index (SLEDAI) > 6 (p = 0.011) compared to patients with inactive disease, SLEDAI < 4. Patient neutrophils transcribed seven to twelve human-specific L1 loci (L1Hs), but only 3 that are full-length and with an intact ORF1. Besides serving as a source of detectable ORF1p, the most abundant transcript encoded a truncated ORF2p reverse transcriptase predicted to remain cytosolic, while the two other encoded an intact full-length ORF2p. A number of genes encoding proteins that influence L1 transcription positively or negatively were altered in patients, particularly those with active disease, compared to healthy controls. Components of nucleic acid sensing and interferon induction were also altered. SLE neutrophils also expressed type I interferon-inducible genes and interferon β, which were substantially reduced after treatment of the cells with drugs known to inhibit ORF2p reverse transcriptase activity.

Conclusions: We identified L1Hs loci that are transcriptionally active in SLE neutrophils, and a reduction in the epigenetic silencing mechanisms that normally counteract L1 transcription. SLE neutrophils contained L1-encoded ORF1p protein, as well as activation of the type I interferon system, which was inhibited by treatment with reverse transcriptase inhibitors. Our findings will enable a deeper analysis of L1 dysregulation and its potential role in SLE pathogenesis.

背景:系统性红斑狼疮(SLE)患者具有抗L1编码的开放阅读框1蛋白(ORF1p)的自身抗体。在此,我们报道了(i)ORF1p来自哪些免疫细胞,(ii)哪些L1基因座具有转录活性,(iii)细胞是否表达L1依赖性干扰素和干扰素刺激的基因,以及(iv)逆转录酶抑制剂对L1 ORF2p的抑制作用。结果:流式细胞仪检测到L1 ORF1p主要在SLE CD66b+CD15+规则粒细胞和低密度粒细胞中,但在其他免疫细胞系中检测到的要少得多。SLE疾病活动指数(SLEDAI)患者中性粒细胞中ORF1p的含量较高 > 6(p = 0.011)与无活动性疾病患者相比,SLEDAI 结论:我们确定了在SLE中性粒细胞中具有转录活性的L1Hs基因座,以及通常抵消L1转录的表观遗传学沉默机制的减少。SLE中性粒细胞含有L1编码的ORF1p蛋白,以及I型干扰素系统的激活,该系统被逆转录酶抑制剂抑制。我们的发现将使我们能够更深入地分析L1失调及其在SLE发病机制中的潜在作用。
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引用次数: 0
Analysis of antibiotic resistance gene cassettes in a newly identified Salmonella enterica serovar Gallinarum strain in Korea. 韩国一株新发现的鸡血清型肠炎沙门氏菌耐药基因磁带分析。
IF 4.9 2区 生物学 Q1 GENETICS & HEREDITY Pub Date : 2023-04-24 DOI: 10.1186/s13100-023-00292-8
Thanh Quang Tran, Minyoung Park, Jong Eun Lee, Soo Hyun Kim, Jae-Ho Jeong, Hyon E Choy

Antimicrobial resistant pathogens are a global health threat driven by the indiscriminate use of antimicrobials. Antimicrobial resistance can be acquired by resistance genes encoded by mobile genetic elements. In this study, we identified a strain of Salmonella enterica serovar Gallinarum (SG4021) from an infected chicken in Korea and characterized the presence of resistance genes in its plasmid by whole genome sequencing. The sequence was then compared with that of a plasmid (P2) from strain SG_07Q015, the only other strain of S. Gallinarum isolated in Korea for which a genome sequence is available. The results revealed that both strains harbored nearly identical DNA carrying antibiotic resistance gene cassettes inserted into integron In2 of the transposable element Tn21, namely an aadA1 resistance gene conferring resistance to aminoglycosides and a sul1 resistance gene conferring resistance to sulfonamide. Interestingly, despite the presence of sul1 in SG4021, an antibiotic sensitivity test revealed that it was sensitive to sulfonamides. Further analysis revealed that this disparity was due to the insertion of a ~ 5 kb ISCR16 sequence downstream of the promoter driving sul1 expression in SG4021. Using various mutants, we showed that the insertion of ISCR16 blocked the expression of the sul1 gene from the upstream promoter. Therefore, the functionality of antimicrobial resistance genes determines phenotypic antimicrobial resistance.

抗微生物药物耐药性病原体是由于滥用抗微生物药物而造成的全球健康威胁。可通过移动遗传元件编码的抗性基因获得抗菌素耐药性。在这项研究中,我们从韩国感染的鸡中鉴定出一株肠炎血清型鸡沙门氏菌(SG4021),并通过全基因组测序鉴定了其质粒中存在抗性基因。然后将该序列与菌株SG_07Q015的质粒(P2)的序列进行比较,SG_07Q015是韩国分离的唯一具有基因组序列的菌株。结果显示,这两株菌株携带几乎相同的DNA,携带插入转座元件Tn21的整合子In2中的抗生素耐药基因盒,即对氨基糖苷具有抗性的aadA1耐药基因和对磺胺具有抗性的sul1耐药基因。有趣的是,尽管SG4021中存在sul1,但抗生素敏感性测试显示它对磺胺类药物敏感。进一步分析表明,这种差异是由于在SG4021中驱动sul1表达的启动子下游插入了约5 kb的ISCR16序列。利用不同的突变体,我们发现ISCR16的插入阻断了上游启动子sul1基因的表达。因此,抗菌素耐药性基因的功能决定了表型抗菌素耐药性。
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引用次数: 2
Telomeric retrotransposons show propensity to form G-quadruplexes in various eukaryotic species. 在各种真核生物中,端粒反转录转座子倾向于形成g -四联体。
IF 4.9 2区 生物学 Q1 GENETICS & HEREDITY Pub Date : 2023-04-10 DOI: 10.1186/s13100-023-00291-9
Pavel Jedlička, Viktor Tokan, Iva Kejnovská, Roman Hobza, Eduard Kejnovský

Background: Canonical telomeres (telomerase-synthetised) are readily forming G-quadruplexes (G4) on the G-rich strand. However, there are examples of non-canonical telomeres among eukaryotes where telomeric tandem repeats are invaded by specific retrotransposons. Drosophila melanogaster represents an extreme example with telomeres composed solely by three retrotransposons-Het-A, TAHRE and TART (HTT). Even though non-canonical telomeres often show strand biased G-distribution, the evidence for the G4-forming potential is limited.

Results: Using circular dichroism spectroscopy and UV absorption melting assay we have verified in vitro G4-formation in the HTT elements of D. melanogaster. Namely 3 in Het-A, 8 in TART and 2 in TAHRE. All the G4s are asymmetrically distributed as in canonical telomeres. Bioinformatic analysis showed that asymmetric distribution of potential quadruplex sequences (PQS) is common in telomeric retrotransposons in other Drosophila species. Most of the PQS are located in the gag gene where PQS density correlates with higher DNA sequence conservation and codon selection favoring G4-forming potential. The importance of G4s in non-canonical telomeres is further supported by analysis of telomere-associated retrotransposons from various eukaryotic species including green algae, Diplomonadida, fungi, insects and vertebrates. Virtually all analyzed telomere-associated retrotransposons contained PQS, frequently with asymmetric strand distribution. Comparison with non-telomeric elements showed independent selection of PQS-rich elements from four distinct LINE clades.

Conclusion: Our findings of strand-biased G4-forming motifs in telomere-associated retrotransposons from various eukaryotic species support the G4-formation as one of the prerequisites for the recruitment of specific retrotransposons to chromosome ends and call for further experimental studies.

背景:规范端粒(端粒酶合成)很容易在富含g的链上形成g -四联体(G4)。然而,在真核生物中有非规范端粒的例子,其中端粒串联重复序列被特定的反转录转座子入侵。黑腹果蝇代表了一个极端的例子,其端粒仅由三个反转录转座子- het - a, TAHRE和TART (HTT)组成。尽管非规范端粒经常表现出链偏g分布,但关于g4形成潜力的证据有限。结果:采用圆二色光谱法和紫外吸收熔融法,证实了黑胃草中HTT元素的g4生成。即Het-A有3个,TART有8个,tare有2个。所有的G4s都不对称地分布在规范端粒中。生物信息学分析表明,潜在四重体序列(PQS)的不对称分布在其他果蝇物种的端粒反转录转座子中也很常见。大多数PQS位于gag基因,PQS密度与较高的DNA序列保守性和有利于g4形成潜力的密码子选择相关。G4s在非规范端粒中的重要性进一步得到了来自各种真核生物物种(包括绿藻、外交家、真菌、昆虫和脊椎动物)的端粒相关反转录转座子的分析的支持。几乎所有分析的端粒相关的反转录转座子都含有PQS,通常具有不对称链分布。与非端粒元素的比较表明,4个不同的LINE分支中pqs丰富的元素是独立选择的。结论:我们在不同真核物种的端粒相关的反转录转座子中发现了链偏置的g4形成基序,支持g4的形成是特定的反转录转座子募集到染色体末端的先决条件之一,需要进一步的实验研究。
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引用次数: 2
Expression of down-regulated ERV LTR elements associates with immune activation in human small-cell lung cancers. 下调ERV LTR元件的表达与人小细胞肺癌的免疫激活相关。
IF 4.9 2区 生物学 Q1 GENETICS & HEREDITY Pub Date : 2023-03-14 DOI: 10.1186/s13100-023-00290-w
Marco Russo, Sara Morelli, Giovanni Capranico

Small-cell lung cancer (SCLC) is an aggressive cancer characterized by immunosuppressive features leading to poor responses to current immunotherapies. Activation of transposable elements (TE) can trigger an innate immune response, which can synergize with immunotherapeutic protocols in patients. However, TE activity in relation to immune gene response is not fully known in human SCLC. Here, we compared TE expression in 104 human SCLC and 24 normal tissues and established their involvement in innate immune responses. We observed that different intergenic TEs, mainly endogenous retroviral (ERV) families, are deregulated in SCLC. Similarly to other cancers, we detected a subset of LTRs that correlate with innate immune gene signatures and cytosolic RNA sensors, such as RIG-I. These LTRs are downregulated in SCLC tumors vs. normal tissues, and are mainly located at transcriptional repressed regions, marked with H3K4me2 in different cell lines. Analyses of different genomic datasets show that chromatin repression is likely due to de-methylase LSD1 activity. Moreover, high expression levels of ERV LTRs predict a better survival upon chemotherapy of SCLC patients. The findings reveal a specific pattern of TE-mediated activation of innate immune genes in SCLC, which can be exploited to establish more effective immunotherapeutic combinations.

小细胞肺癌(SCLC)是一种侵袭性癌症,其特征是免疫抑制,导致对当前免疫疗法的反应较差。转座因子(TE)的激活可以触发先天免疫反应,这可以与患者的免疫治疗方案协同作用。然而,TE活性与免疫基因反应的关系在人类SCLC中尚不完全清楚。在这里,我们比较了104例人类SCLC和24例正常组织中的TE表达,并确定了它们参与先天免疫反应。我们观察到不同的基因间te,主要是内源性逆转录病毒(ERV)家族,在SCLC中被解除调控。与其他癌症类似,我们检测到与先天免疫基因特征和细胞质RNA传感器(如rig - 1)相关的ltr子集。与正常组织相比,这些LTRs在SCLC肿瘤中下调,主要位于转录抑制区,在不同细胞系中以H3K4me2标记。对不同基因组数据集的分析表明,染色质抑制可能是由于去甲基化酶LSD1的活性。此外,ERV LTRs的高表达水平预示着SCLC患者化疗后更好的生存。研究结果揭示了te介导的SCLC先天免疫基因激活的特定模式,这可以用来建立更有效的免疫治疗组合。
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引用次数: 0
Mobility of mPing and its associated elements is regulated by both internal and terminal sequences. mPing及其相关元件的迁移受内部序列和末端序列的调控。
IF 4.9 2区 生物学 Q1 GENETICS & HEREDITY Pub Date : 2023-02-11 DOI: 10.1186/s13100-023-00289-3
Priscilla S Redd, Stephanie Diaz, David Weidner, Jazmine Benjamin, C Nathan Hancock

Background: DNA transposable elements are mobilized by a "cut and paste" mechanism catalyzed by the binding of one or more transposase proteins to terminal inverted repeats (TIRs) to form a transpositional complex. Study of the rice genome indicates that the mPing element has experienced a recent burst in transposition compared to the closely related Ping and Pong elements. A previously developed yeast transposition assay allowed us to probe the role of both internal and terminal sequences in the mobilization of these elements.

Results: We observed that mPing and a synthetic mPong element have significantly higher transposition efficiency than the related autonomous Ping and Pong elements. Systematic mutation of the internal sequences of both mPing and mPong identified multiple regions that promote or inhibit transposition. Simultaneous alteration of single bases on both mPing TIRs resulted in a significant reduction in transposition frequency, indicating that each base plays a role in efficient transposase binding. Testing chimeric mPing and mPong elements verified the important role of both the TIRs and internal regulatory regions. Previous experiments showed that the G at position 16, adjacent to the 5' TIR, allows mPing to have higher mobility. Alteration of the 16th and 17th base from mPing's 3' end or replacement of the 3' end with Pong 3' sequences significantly increased transposition frequency.

Conclusions: As the transposase proteins were consistent throughout this study, we conclude that the observed transposition differences are due to the element sequences. The presence of sub-optimal internal regions and TIR bases supports a model in which transposable elements self-limit their activity to prevent host damage and detection by host regulatory mechanisms. Knowing the role of the TIRs, adjacent sub-TIRs, and internal regulatory sequences allows for the creation of hyperactive elements.

背景:DNA转座因子通过一个或多个转座酶蛋白与末端倒置重复序列(TIRs)结合催化的“剪切和粘贴”机制被动员起来,形成转座复合物。对水稻基因组的研究表明,与与之密切相关的Ping和Pong元件相比,mPing元件最近经历了一次爆发性的转位。先前开发的酵母转位试验使我们能够探测内部和末端序列在这些元件动员中的作用。结果:我们观察到mPing和合成的mPong元件的转位效率明显高于相关的自主Ping和Pong元件。mPing和mPong内部序列的系统突变发现了促进或抑制转位的多个区域。同时改变两个mPing TIRs上的单个碱基导致转座频率显著降低,表明每个碱基都在有效的转座酶结合中发挥作用。嵌合mPing和mPong元件的测试证实了tir和内部调控区域的重要作用。先前的实验表明,位置16的G与5' TIR相邻,使得mPing具有更高的迁移率。从mPing的3'端改变第16和第17个碱基或用Pong的3'序列替换3'端显著增加了转位频率。结论:由于转座酶蛋白在整个研究中是一致的,我们得出结论,观察到的转座差异是由于元件序列所致。次优内部区域和TIR碱基的存在支持了转座因子自我限制其活性以防止宿主损伤和被宿主调节机制检测的模型。了解tir、相邻子tir和内部调控序列的作用,可以创建多活性元件。
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引用次数: 3
Accelerating Self-Assembly of Crisscross Slat Systems 加速交叉板系的自组装
IF 4.9 2区 生物学 Q1 GENETICS & HEREDITY Pub Date : 2023-01-01 DOI: 10.4230/LIPIcs.DNA.29.7
David Doty, Hunter Fleming, Daniel Hader, Matthew J. Patitz, Lukas A. Vaughan
We present an abstract model of self-assembly of systems composed of “crisscross slats”, which have been experimentally implemented as a single-stranded piece of DNA [21] or as a complete DNA origami structure [28]. We then introduce a more physically realistic “kinetic” model and show how important constants in the model were derived and tuned, and compare simulation-based results to experimental results [21,28]. Using these models, we show how we can apply optimizations to designs of slat systems in order to lower the numbers of unique slat types required to build target structures. In general, we apply two types of techniques to achieve greatly reduced numbers of slat types. Similar to the experimental work implementing DNA origami-based slats, in our designs the slats oriented in horizontal and vertical directions are each restricted to their own plane and sets of them overlap each other in square regions which we refer to as macrotiles . Our first technique extends their previous work of reusing slat types within macrotiles and requires analyses of binding domain patterns to determine the potential for errors consisting of incorrect slat types attaching at undesired translations and reflections. The second technique leverages the power of algorithmic self-assembly to efficiently reuse entire macrotiles which self-assemble in patterns following designed algorithms that dictate the dimensions and patterns of growth. Using these designs, we demonstrate that in kinetic simulations the systems with reduced numbers of slat types self-assemble more quickly than those with greater numbers. This provides evidence that such optimizations will also result in greater assembly speeds in experimental systems. Furthermore, the reduced numbers of slat types required have the potential to vastly reduce the cost and number of lab steps for crisscross assembly experiments.
我们提出了一个由“交叉板条”组成的系统自组装的抽象模型,该模型已被实验实现为单链DNA[21]或完整的DNA折纸结构[28]。然后,我们引入了一个更现实的“动力学”模型,并展示了模型中重要的常数是如何推导和调整的,并将基于模拟的结果与实验结果进行了比较[21,28]。使用这些模型,我们展示了如何将优化应用于板条系统的设计,以减少构建目标结构所需的独特板条类型的数量。一般来说,我们采用两种技术来大大减少板条类型的数量。类似于基于DNA折纸的板条的实验工作,在我们的设计中,水平方向和垂直方向的板条都被限制在自己的平面上,并且它们的集合在我们称之为宏块的方形区域中相互重叠。我们的第一项技术扩展了他们之前在宏块中重用板条类型的工作,需要对绑定域模式进行分析,以确定在不需要的翻译和反射上附着不正确的板条类型所构成的潜在错误。第二种技术利用算法自组装的能力,有效地重用整个宏块,这些宏块按照指定增长的维度和模式的设计算法以模式进行自组装。利用这些设计,我们证明了在动力学模拟中,具有较少数量的板条类型的系统比具有较多数量的系统自组装速度更快。这提供的证据表明,这种优化也将导致更大的组装速度在实验系统。此外,所需的板条类型数量的减少有可能大大降低交叉组装实验的成本和实验室步骤的数量。
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引用次数: 1
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Mobile DNA
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