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1.
J Nanobiotechnology ; 22(1): 142, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38561751

RESUMO

Seesaw circuits are essential for molecular computing and biosensing. However, a notable limitation of seesaw circuits lies in the irreversible depletion of components, precluding the attainment of system recovery and rendering nucleic acid circuits non-reusable. We developed a brand-new method for creating controllable and reusable seesaw circuits. By using the nicking endonucleases Nt.BbvCI and Nt.Alwi, we removed "functional components" while keeping the "skeletal components" for recurrent usage. T-inputs were introduced, increasing the signal-to-noise ratio of AND logic from 2.68 to 11.33 and demonstrating compatibility. We identified the logic switching feature and verified that it does not impair circuit performance. We also built intricate logic circuits, such as OR-AND gate, to demonstrate the versatility of our methodology. This controllable reusability extends the applications of nanotechnology and bioengineering, enhancing the practicality and efficiency of these circuits across various domains.


Assuntos
DNA , Ácidos Nucleicos , Endonucleases , Bioengenharia
2.
Nat Commun ; 15(1): 2890, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38570537

RESUMO

DNA double-strand breaks (DSBs) can be repaired by several pathways. In eukaryotes, DSB repair pathway choice occurs at the level of DNA end resection and is controlled by the cell cycle. Upon cell cycle-dependent activation, cyclin-dependent kinases (CDKs) phosphorylate resection proteins and thereby stimulate end resection and repair by homologous recombination (HR). However, inability of CDK phospho-mimetic mutants to bypass this cell cycle regulation, suggests that additional cell cycle regulators may be important. Here, we identify Dbf4-dependent kinase (DDK) as a second major cell cycle regulator of DNA end resection. Using inducible genetic and chemical inhibition of DDK in budding yeast and human cells, we show that end resection and HR require activation by DDK. Mechanistically, DDK phosphorylates at least two resection nucleases in budding yeast: the Mre11 activator Sae2, which promotes resection initiation, as well as the Dna2 nuclease, which promotes resection elongation. Notably, synthetic activation of DDK allows limited resection and HR in G1 cells, suggesting that DDK is a key component of DSB repair pathway selection.


Assuntos
Quebras de DNA de Cadeia Dupla , Proteínas de Saccharomyces cerevisiae , Humanos , Ciclo Celular , Recombinação Homóloga , Divisão Celular , Endonucleases/metabolismo , Quinases Ciclina-Dependentes/genética , Quinases Ciclina-Dependentes/metabolismo , DNA , Reparo do DNA , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
3.
CRISPR J ; 7(2): 120-130, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38635326

RESUMO

CRISPR-Cas systems have proven effective in a variety of applications due to their ease of use and relatively high editing efficiency. Yet, any individual CRISPR-Cas system has inherent limitations, necessitating a diversity of RNA-guided nucleases to suit applications with distinct needs. We searched through metagenomic sequences to identify RNA-guided nucleases and found enzymes from diverse CRISPR-Cas types and subtypes, the most promising of which we developed into gene-editing platforms. Based on prior annotations of the metagenomic sequences, we establish the likely taxa and sampling locations where Class 2 CRISPR-Cas systems active in eukaryotes may be found. The newly discovered systems show robust capabilities as gene editors and base editors.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Sistemas CRISPR-Cas/genética , Endonucleases/genética , RNA
4.
Arch Oral Biol ; 162: 105955, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38479279

RESUMO

OBJECTIVE: This meta-analysis was conducted to investigate the relationship between ERCC1 and XPC polymorphisms and the risk of head and neck cancer (HNC), incorporating more studies and additional analyses. DESIGN: An exhaustive search of various databases, including PubMed/Medline, Web of Science, Scopus, and Cochrane Library was carried out, up until November 18, 2023, to identify pertinent studies. The Review Manager 5.3 software was employed to calculate the effect sizes, which were presented as the odds ratio (OR) along with a 95% confidence interval (CI). RESULTS: The study found that the T allele (OR = 1.11; p-value = 0.02; 95%CI: 1.02, 1.22) and the TT genotype rs2228000 polymorphism in both the homozygous model (OR = 1.61, p-value = 0.02; 95%CI: 1.07, 2.42) and the recessive model (OR = 1.53; p-value = 0.02; 95%CI: 1.06, 2.22) had statistically significant associations. However, no significant associations were found for rs11615, rs3212986, rs735482, rs2228001, and PAT polymorphisms in any genetic models. CONCLUSIONS: The meta-analysis revealed significant associations for the T allele and TT genotype rs2228000 polymorphism, but not for rs11615, rs3212986, rs735482, rs2228001, and PAT polymorphisms. The results highlight the impact of factors such as ethnicity, cancer subtype, and control source on these associations, emphasizing the intricate nature of genetic interactions in disease risk.


Assuntos
Carcinoma , Neoplasias de Cabeça e Pescoço , Humanos , Proteínas de Ligação a DNA/genética , Predisposição Genética para Doença , Polimorfismo Genético , Neoplasias de Cabeça e Pescoço/genética , Polimorfismo de Nucleotídeo Único , Endonucleases/genética
5.
Chem Commun (Camb) ; 60(28): 3778-3781, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38494893

RESUMO

A twice-walk strategy based on a three-dimensional (3D) cleat-equipped DNA walking machine with a high signal amplification efficiency was investigated for ultrasensitive detection of miRNA. Impressively, addition of duplex-specific nuclease (DSN) just once drove the twice-walk strategy, making the strategy simpler. With the advantages of being simple, rapid and ultrasensitive, the biosensor offers potential for use in early clinical diagnosis.


Assuntos
Técnicas Biossensoriais , MicroRNAs , MicroRNAs/genética , DNA , Técnicas Biossensoriais/métodos , Endonucleases , Técnicas de Amplificação de Ácido Nucleico/métodos , Limite de Detecção
6.
Phys Chem Chem Phys ; 26(11): 8919-8931, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38426850

RESUMO

Homing endonucleases (HEs) are highly specific DNA cleaving enzymes, with I-PpoI having been suggested to use a single metal to accelerate phosphodiester bond cleavage. Although an I-PpoI mechanism has been proposed based on experimental structural data, no consensus has been reached regarding the roles of the metal or key active site amino acids. This study uses QM cluster and QM/MM calculations to provide atomic-level details of the I-PpoI catalytic mechanism. Minimal QM cluster and large-scale QM/MM models demonstrate that the experimentally-proposed pathway involving direct Mg2+ coordination to the substrate coupled with leaving group protonation through a metal-activated water is not feasible due to an inconducive I-PpoI active site alignment. Despite QM cluster models of varying size uncovering a pathway involving leaving group protonation by a metal-activated water, indirect (water-mediated) metal coordination to the substrate is required to afford this pathway, which renders this mechanism energetically infeasible. Instead, QM cluster models reveal that the preferred pathway involves direct Mg2+-O3' coordination to stabilize the charged substrate and assist leaving group departure, while H98 activates the water nucleophile. These calculations also underscore that both catalytic residues that directly interact with the substrate and secondary amino acids that position or stabilize these residues are required for efficient catalysis. QM/MM calculations on the solvated enzyme-DNA complex verify the preferred mechanism, which is fully consistent with experimental kinetic, structural, and mutational data. The fundamental understanding of the I-PpoI mechanism of action, gained from the present work can be used to further explore potential uses of this enzyme in biotechnology and medicine, and direct future computational investigations of other members of the understudied HE family.


Assuntos
Endonucleases , Metais , Metais/metabolismo , DNA/química , Catálise , Água
7.
Biochem Biophys Res Commun ; 704: 149713, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38428304

RESUMO

As life expectancy continues to increase, age-related kidney diseases are becoming more prevalent. Chronic kidney disease (CKD) is not only a consequence of aging but also a potential accelerator of aging process. Here we report the pivotal role of podocyte ERCC1, a DNA repair factor, in maintaining glomerular integrity and a potential effect on multiple organs. Podocyte-specific ERCC1-knockout mice developed severe proteinuria, glomerulosclerosis, and renal failure, accompanied by a significant increase in glomerular DNA single-strand breaks (SSBs) and double-strand breaks (DSBs). ERCC1 gene transfer experiment in the knockout mice attenuated proteinuria and glomerulosclerosis with reduced DNA damage. Notably, CD44+CD8+ memory T cells, indicative of T-cell senescence, were already elevated in the peripheral blood of knockout mice at 10 weeks old. Additionally, levels of senescence-associated secretory phenotype (SASP) factors were significantly increased in both the circulation and multiple organs of the knockout mice. In older mice and human patients, we observed an accumulation of DSBs and an even greater buildup of SSBs in glomeruli, despite no significant reduction in ERCC1 expression with age in mice. Collectively, our findings highlight the crucial role of ERCC1 in repairing podocyte DNA damage, with potential implications for inflammation in various organs.


Assuntos
Nefropatias , Podócitos , Humanos , Camundongos , Animais , Podócitos/metabolismo , Glomérulos Renais/metabolismo , Nefropatias/metabolismo , Camundongos Knockout , Proteinúria/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Endonucleases/genética , Endonucleases/metabolismo
8.
Methods Mol Biol ; 2760: 169-198, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38468089

RESUMO

Class II Type V endonucleases have increasingly been adapted to develop sophisticated and easily accessible synthetic biology tools for genome editing, transcriptional regulation, and functional genomic screening in a wide range of organisms. One such endonuclease, Cas12a, presents itself as an attractive alternative to Cas9-based systems. The ability to mature its own guide RNAs (gRNAs) from a single transcript has been leveraged for easy multiplexing, and its lack of requirement of a tracrRNA element, also allows for short gRNA expression cassettes. To extend these functionalities into the industrially relevant oleaginous yeast Yarrowia lipolytica, we developed a set of CRISPR-Cas12a vectors for easy multiplexed gene knockout, repression, and activation. We further extended the utility of this CRISPR-Cas12a system to functional genomic screening by constructing a genome-wide guide library targeting every gene with an eightfold coverage. Pooled CRISPR screens conducted with this library were used to profile Cas12a guide activities and develop a machine learning algorithm that could accurately predict highly efficient Cas12a gRNA. In this protocols chapter, we first present a method by which protein coding genes may be functionally disrupted via indel formation with CRISPR-Cas12a systems. Further, we describe how Cas12a fused to a transcriptional regulator can be used in conjunction with shortened gRNA to achieve transcriptional repression or activation. Finally, we describe the design, cloning, and validation of a genome-wide library as well as a protocol for the execution of a pooled CRISPR screen, to determine guide activity profiles in a genome-wide context in Y. lipolytica. The tools and strategies discussed here expand the list of available synthetic biology tools for facile genome engineering in this industrially important host.


Assuntos
Edição de Genes , Yarrowia , Edição de Genes/métodos , Sistemas CRISPR-Cas/genética , Yarrowia/genética , Yarrowia/metabolismo , RNA Guia de Sistemas CRISPR-Cas , Endonucleases/genética , Testes Genéticos
9.
Methods Mol Biol ; 2760: 253-265, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38468093

RESUMO

Positive selection screens are high-throughput assays to characterize novel enzymes from environmental samples and enrich for more powerful variants from libraries in applications such as biodiversity mining and directed evolution. However, overly stringent selection can limit the power of these screens due to a high false-negative rate. To create a more flexible and less restrictive screen for novel programmable DNA endonucleases, we developed a novel I-SceI-based platform. In this system, mutant E. coli genomes are cleaved upon induction of I-SceI to inhibit cell growth. Growth is rescued in an activity-dependent manner by plasmid curing or cleavage of the I-SceI expression plasmid via endonuclease candidates. More active candidates more readily proliferate and overtake growth of less active variants leading to enrichment. While demonstrated here with Cas9, this protocol can be readily adapted to any programmable DNA endonuclease and used to characterize single candidates or to enrich more powerful variants from pooled candidates or libraries.


Assuntos
Proteínas de Saccharomyces cerevisiae , Proteínas de Saccharomyces cerevisiae/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Plasmídeos/genética , Endonucleases/genética
10.
PLoS Biol ; 22(3): e3002514, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38483978

RESUMO

The clustered regularly interspaced short palindromic repeat (CRISPR)-Cas12a system is a powerful tool in gene editing; however, crRNA-DNA mismatches might induce unwanted cleavage events, especially at the distal end of the PAM. To minimize this limitation, we engineered a hyper fidelity AsCas12a variant carrying the mutations S186A/R301A/T315A/Q1014A/K414A (termed HyperFi-As) by modifying amino acid residues interacting with the target DNA and crRNA strand. HyperFi-As retains on-target activities comparable to wild-type AsCas12a (AsCas12aWT) in human cells. We demonstrated that HyperFi-As has dramatically reduced off-target effects in human cells, and HyperFi-As possessed notably a lower tolerance to mismatch at the position of the PAM-distal region compared with the wild type. Further, a modified single-molecule DNA unzipping assay at proper constant force was applied to evaluate the stability and transient stages of the CRISPR/Cas ribonucleoprotein (RNP) complex. Multiple states were sensitively detected during the disassembly of the DNA-Cas12a-crRNA complexes. On off-target DNA substrates, the HyperFi-As-crRNA was harder to maintain the R-loop complex state compared to the AsCas12aWT, which could explain exactly why the HyperFi-As has low off-targeting effects in human cells. Our findings provide a novel version of AsCas12a variant with low off-target effects, especially capable of dealing with the high off-targeting in the distal region from the PAM. An insight into how the AsCas12a variant behaves at off-target sites was also revealed at the single-molecule level and the unzipping assay to evaluate multiple states of CRISPR/Cas RNP complexes might be greatly helpful for a deep understanding of how CRISPR/Cas behaves and how to engineer it in future.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Humanos , Sistemas CRISPR-Cas/genética , RNA Guia de Sistemas CRISPR-Cas , Endonucleases/genética , Endonucleases/metabolismo , DNA/genética
11.
Wiley Interdiscip Rev RNA ; 15(2): e1836, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38453211

RESUMO

Protein-only RNase P (PRORP) is an essential enzyme responsible for the 5' maturation of precursor tRNAs (pre-tRNAs). PRORPs are classified into three categories with unique molecular architectures, although all three classes of PRORPs share a mechanism and have similar active sites. Single subunit PRORPs, like those found in plants, have multiple isoforms with different localizations, substrate specificities, and temperature sensitivities. Most recently, Arabidopsis thaliana PRORP2 was shown to interact with TRM1A and B, highlighting a new potential role between these enzymes. Work with At PRORPs led to the development of a ribonuclease that is being used to protect against plant viruses. The mitochondrial RNase P complex, found in metazoans, consists of PRORP, TRMT10C, and SDR5C1, and has also been shown to have substrate specificity, although the cause is unknown. Mutations in mitochondrial tRNA and mitochondrial RNase P have been linked to human disease, highlighting the need to continue understanding this complex. The last class of PRORPs, homologs of Aquifex RNase P (HARPs), is found in thermophilic archaea and bacteria. This most recently discovered type of PRORP forms a large homo-oligomer complex. Although numerous structures of HARPs have been published, it is still unclear how HARPs bind pre-tRNAs and in what ratio. There is also little investigation into the substrate specificity and ideal conditions for HARPs. Moving forward, further work is required to fully characterize each of the three classes of PRORP, the pre-tRNA binding recognition mechanism, the rules of substrate specificity, and how these three distinct classes of PRORP evolved. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.


Assuntos
Arabidopsis , Ribonuclease P , Humanos , Ribonuclease P/genética , Ribonuclease P/química , Ribonuclease P/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo , Ribonucleases/metabolismo , Endonucleases/metabolismo , RNA de Transferência/genética , RNA de Transferência/metabolismo , RNA/metabolismo , Arabidopsis/genética , Especificidade por Substrato
12.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 46(1): 11-18, 2024 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-38433625

RESUMO

Objective To investigate the effect of staphylococcal nuclease and tudor domain containing 1(SND1) on the biological function of osteosarcoma cells and decipher the mechanism of SND1 in regulating ferroptosis in osteosarcoma cells via SLC7A11. Methods Human osteoblasts hFOB1.19 and osteosarcoma cell lines Saos-2,U2OS,HOS,and 143B were cultured,in which the expression level of SND1 was determined.Small interfering RNA was employed to knock down the expression of SND1(si-SND1) in the osteosarcoma cell line HOS and 143B.The CCK8 assay kit,colony formation assay,and Transwell assay were employed to examine the effect of SND1 expression on the biological function of osteosarcoma cells.Furthermore,we altered the expression of SND1 and SLC7A11 in osteosarcoma cells to investigate the effect of SND1 on osteosarcoma ferroptosis via SLC7A11. Results The mRNA and protein levels of SND1 in Saos-2,U2OS,HOS,and 143B cells were higher than those in hFOB1.19 cells(all P<0.01).Compared with the control group,transfection with si-SND1 down-regulated the expression level of SND1 in HOS and 143B cells(all P<0.01),decreased the viability of HOS and 143B cells,reduced the number of colony formation,and inhibited cell invasion and migration(all P<0.001).The ferroptosis inducer Erastin promoted the apoptosis of HOS and 143B cells,while the ferroptosis inhibitor Ferrostatin-1 improved the viability of HOS and 143B cells(all P<0.001).After SND-1 knockdown,Erastin reduced the viability of HOS and 143B cells,while Ferrostatin-1 restored the cell viability(all P<0.001).After treatment with Erastin in the si-SND1 group,the levels of iron and malondialdehyde were elevated,and the level of glutathione was lowered(all P<0.001).The results of in vivo experiments showed that SND1 knockdown inhibited the mass of the transplanted tumor in 143B tumor-bearing nude mice(P<0.001).Knocking down the expression of SND1 resulted in down-regulated SLC7A11 expression(all P<0.001) and increased ferroptosis in HOS and 143B cells(P<0.001,P=0.020). Conclusions SND1 presents up-regulated expression in osteosarcoma cells.It may inhibit ferroptosis by up-regulating the expression of SLC7A11,thereby improving the viability of osteosarcoma cells.


Assuntos
Neoplasias Ósseas , Cicloexilaminas , Eliptocitose Hereditária , Ferroptose , Osteossarcoma , Fenilenodiaminas , Animais , Humanos , Camundongos , Sistema y+ de Transporte de Aminoácidos , Endonucleases , Camundongos Nus , Nuclease do Micrococo , Domínio Tudor
13.
Talanta ; 273: 125909, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38490020

RESUMO

The in vitro detection of circulating tumor cells (CTCs) has been proven as a vital method for early diagnosis and evaluation of cancer metastasis, since the existence and number fluctuation of CTCs have shown close correlation with clinical outcomes. However, it remains difficult and technically challenging to realize accurate CTCs detection, due to the rarity of CTCs in the blood samples with complex components. Herein, we reported a CTCs in vitro detection strategy, utilizing a loop amplification strategy based on DNA tetrahedron and nicking endonuclease reaction, as well as the anti-background interference based on lanthanide metal luminescence strategy. In this work, a detection system (ATDN-MLLPs) composed of an aptamer-functionalized tetrahedral DNA nanostructure (ATDN) and magnetic lanthanide luminescent particles (MLLPs) was developed. ATDN targeted the tumor cells via aptamer-antigen recognition and extended three hybridizable target DNA segments from the apex of a DNA tetrahedron to pair with probe DNA on MLLPs. Then, the nicking endonuclease (Nt.BbvCI) recognized the formed double-strand DNA and nicked the probe DNA to release the target DNA for recycling, and the released TbNps served as a high signal-to-noise ratio fluorescence signal source for CTCs detection. With a detection limit of 5 cells/mL, CTCs were selectively screened throughout a linear response range of low orders of magnitude. In addition, the ATDN-MLLPs system was attempted to detect possible existence of CTCs in biological samples in vitro.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Células Neoplásicas Circulantes , Humanos , Endonucleases/química , Luminescência , DNA/genética , DNA/química , Sondas de DNA/química , Metais , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/métodos
14.
Bioorg Chem ; 144: 107118, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38330720

RESUMO

Synthetic DNA-protein conjugates have found widespread applications in diagnostics and therapeutics, prompting a growing interest in developing chemical biology methodologies for the precise and site-specific preparation of covalent DNA-protein conjugates. In this review article, we concentrate on techniques to achieve precise control over the structural and site-specific aspects of DNA-protein conjugates. We summarize conventional methods involving unnatural amino acids and self-labeling proteins, accompanied by a discussion of their potential limitations. Our primary focus is on introducing HUH endonuclease as a novel generation of fusion protein tags for DNA-protein conjugate preparation. The detailed conjugation mechanisms and structures of representative endonucleases are surveyed, showcasing their advantages as fusion protein tag in sequence selectivity, biological orthogonality, and no requirement for DNA modification. Additionally, we present the burgeoning applications of HUH-tag-based DNA-protein conjugates in protein assembly, biosensing, and gene editing. Furthermore, we delve into the future research directions of the HUH-tag, highlighting its significant potential for applications in the biomedical and DNA nanotechnology fields.


Assuntos
Endonucleases , Proteínas , Proteínas/química , DNA/química , Aminoácidos , Nanotecnologia
15.
Int J Biol Macromol ; 262(Pt 1): 129902, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38307426

RESUMO

In situ imaging of microRNA (miRNA) content and distribution is valuable for monitoring tumor progression. However, tumor specific in situ imaging remains a challenge due to low miRNA abundance, lack of biological compatibility, and poor specificity. In this study, we designed a DNA tetrahedral framework complex with hairpins (DTF-HPAP) consisting of an apurinic/apyrimidinic site (AP site) that could be specifically recognized and cleaved by apurinic/apyrimidinic endonuclease 1 (APE1). Efficient and specific in situ imaging of miR-21 in tumors was thus achieved through catalytic hairpin assembly (CHA) reaction. In this study, DTF-HPAP was successfully constructed to trigger the cumulative amplification of fluorescence signal in situ. The specificity, sensitivity and serum stability of DTF-HPAP were verified in vitro, and DTF-HPAP could be easily taken up by cells, acting as a biosensor to detect tumors in mice. Furthermore, we verified the ability of DTF-HPAP to specifically image miR-21 in tumors, and demonstrated its capability for tumor-specific imaging in clinical samples.


Assuntos
Técnicas Biossensoriais , MicroRNAs , Neoplasias , Camundongos , Animais , MicroRNAs/genética , Endonucleases , Catálise , Técnicas Biossensoriais/métodos
16.
STAR Protoc ; 5(1): 102866, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38329880

RESUMO

Cleavage under targets & release using nuclease (CUT&RUN) is a technique for identifying genomic sites where proteins or histone modifications are present in chromatin in permeabilized cells. Here, we present a fluorescence-based protocol to quantitatively titrate CUT&RUN buffer components, for efficient cell permeabilization and retention of target epitopes on chromatin. We describe steps for capturing cells on concanavalin A beads and using a fluorescently labeled secondary antibody to titrate concentrations of digitonin and NaCl in CUT&RUN buffers. We then detail procedures for fluorescence imaging to identify optimal conditions. For complete details on the use and execution of this protocol, please refer to Lerner et al.1.


Assuntos
Anticorpos , Cromatina , Endonucleases , Epitopos , Genômica
17.
Talanta ; 272: 125835, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38422905

RESUMO

The expression level of human apurinic/apyrimidinic endonuclease 1 (APE1) is closely associated with the onset of various diseases, establishing it as a crucial clinical biomarker and a target in anti-cancer efforts. This study accomplished colorimetric and visual detection of APE1 by harnessing its endonuclease activity through catalytic hairpin self-assembly (CHA) and G-quadruplex/hemin DNAzyme. Optimization of the freedom degrees of the G-rich sequence significantly improved the detection performance of the strategy by influencing DNAzyme formation. Additionally, we replaced the signal reporting system with a molecular beacon to develop a fluorescence detection strategy, which served as an extension of the signal amplification system for validation and signal readout. The fluorescent probe method achieved a detection limit of 3.37 × 10-4 U/mL, while the colorimetric method yielded a detection limit of 6.5 × 10-3 U/mL, with a linear range spanning from 0.01 to 0.25 U/mL. Subsequently, the colorimetric approach effectively assessed APE1 activity in biological samples and facilitated the screening of APE1 activity inhibitors. Furthermore, this CHA/G-quadruplex/hemin DNAzyme strategy was adapted for the colorimetric detection of adenosine, showcasing its broad applicability across various biomarkers. The developed colorimetric analytical strategy represents a pivotal biosensing platform for diagnosing and treating diseases.


Assuntos
Técnicas Biossensoriais , DNA Catalítico , Quadruplex G , Humanos , DNA Catalítico/metabolismo , Hemina , Colorimetria/métodos , Técnicas Biossensoriais/métodos , Endonucleases/metabolismo
18.
Biosci Rep ; 44(3)2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38358895

RESUMO

BACKGROUND: Human umbilical cord mesenchymal stem cells (hUCMSCs) are promising seed cells in bone tissue engineering. circRNA and N6-methyladenosine (m6A) RNA methylation play important roles in osteogenic differentiation. Here, we investigated the potential relevance of a critical circRNA, hsa_circ_0003376 (circCTTN), and methyltransferase-like 3 (METTL3) in osteogenic differentiation of hUCMSCs. METHODS: Expression of circCTTN after hUCMSC osteogenic induction was detected by qRT-PCR. Three databases (RMBase v2.0, BERMP, and SRAMP) were used to predict m6A sites of circCTTN. RNA was enriched by methylated RNA immunoprecipitation (MeRIP), followed by quantitative real-time polymerase chain reaction to detect m6A level of circCTTN after METTL3 overexpression and osteogenic induction. RNA pull-down, Western blotting, and protein mass spectrometry were performed to investigate the potential mechanisms by which METTL3 promoted m6A modification of circCTTN. Bioinformatic analyses based on database (STRING) search and co-immunoprecipitation were used to analyze the proteins that interacted with METTL3. RESULTS: Overexpression of METTL3 promoted osteogenic differentiation of hUCMSCs and increased m6A level of circCTTN. Two potential m6A modification sites of circCTTN were predicted. No direct interaction between METTL3 and circCTTN was observed. Thirty-one proteins were pulled down by probes specific for circCTTN, including NOP2, and two m6A reading proteins, EIF3A and SND1. Bioinformatics analysis and co-immunoprecipitation showed that METTL3 interacted with EIF3A indirectly through NOP2. CONCLUSIONS: METTL3 promotes the osteogenic differentiation of hUCMSCs by increasing the m6A level of circCTTN. However, METTL3 does not bind directly to circCTTN. METTL3 interacts with circCTTN indirectly through NOP2 and EIF3A.


Assuntos
Células-Tronco Mesenquimais , Metiltransferases , Osteogênese , Humanos , Endonucleases , Metiltransferases/genética , Osteogênese/genética , RNA , RNA Circular/genética , RNA Circular/metabolismo , Cordão Umbilical
19.
Eur Rev Med Pharmacol Sci ; 28(2): 584-602, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38305603

RESUMO

OBJECTIVE: Clear cell renal cell carcinoma (ccRCC) is the most common type of cancer, and its molecular pathogenesis is unclear. In this study, we investigated the prognostic value of essential meiotic endonuclease 1 (EME1) in kidney renal clear cell carcinoma (KIRC). MATERIALS AND METHODS: We downloaded the RNA-Seq expression of 526 KIRC tissues and 72 normal tissues from the TCGA database and the corresponding clinical data. The gene expression profiles associated with four clear cell renal cell carcinomas were downloaded from the GEO database for analysis. The expression of EME1 in clear renal cell carcinoma and its correlation with the clinical baseline data were analyzed. Kaplan-Meier survival curve analysis was performed to assess the relationship between EME1 and patient survival. Enrichment analysis was performed to elucidate the possible functions of EME1. We also analyzed the relationship between the EME1 expression and immune infiltration through TIMER2.0 and TISIDB online databases as well as the relationship between EME1 and common immune checkpoints. RESULTS: EME1 was identified as a risk factor for overall survival in clear cell renal cell carcinoma with a hazard ratio of 3.201 (95% confidence interval: 2.430-4.215; p < 0.001). EME1 was highly expressed in KIRC compared to that in normal tissues (p < 0.001) and in the worse TNM stages and late stages (stage 3/4) (p < 0.001). High EME1 expression was strongly associated with the advanced T stage (p = 0.003), advanced N stage (p = 0.002), and advanced M stage (p = 0.006). Research data on KIRC were simultaneously collected and analyzed from the GEO database, including GSE40435, GSE53000, GSE68417, and GSE53757. EME1 predicted the survival status in KIRC patients (AUC = 0.62). We further established a nomogram including the correlation between the high and low EME1 expression, and EME1 was found to contribute to the prediction of the probability of patient survival with a c-index = 0.796. Kaplan-Meier analysis revealed a lower likelihood of survival with a high EME1 expression (p < 0.001). In addition, further bioinformatics analysis suggested that EME1 may be associated with the extent of immune infiltration in KIRC. CONCLUSIONS: An increased expression of EME1 in KIRC is thus associated with advanced clinicopathological features, possibly acting as a potential biomarker of poor prognosis in KIRC.


Assuntos
Adenocarcinoma de Células Claras , Carcinoma de Células Renais , Neoplasias Renais , Humanos , Carcinoma de Células Renais/genética , Prognóstico , Rim , Endonucleases , Neoplasias Renais/genética
20.
Arch Microbiol ; 206(3): 125, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38411841

RESUMO

Non-specific endonucleases can be used for the digestion of nucleic acids because they hydrolyze DNA/RNA into 3-5 base pairs (bp) length oligonucleotide fragments without strict selectivity. In this work, a novel non-specific endonuclease from Pseudomonas fluorescens (PfNuc) with high activities for both DNA and RNA was successfully cloned and expressed in Escherichia coli. The production of PfNuc in flask scale could be achieved to 1.73 × 106 U/L and 4.82 × 106 U/L for DNA and RNA by investigation of the culture and induction conditions. The characterization of PfNuc indicated that it was Mg2+-dependent and the catalytic activity was enhanced by 3.74 folds for DNA and 1.06 folds for RNA in the presence of 5 mM Mg2+. The specific activity of PfNuc for DNA was 1.44 × 105 U/mg at pH 8.0 and 40 °C, and 3.93 × 105 U/mg for RNA at pH 8.5 and 45 °C. The Km of the enzyme for both DNA and RNA was close to 43 µM. The Vmax was 6.40 × 105 U/mg and 1.11 × 106 U/mg for DNA and RNA, respectively. There was no observed activity loss when PfNuc was stored at 4 °C and - 20 °C after 28 days or 10 repeated freeze-thaw cycles at - 80 °C. Molecular docking revealed that PfNuc formed 17 and 19 hydrogen bonds with single-stranded RNA and double-stranded DNA, respectively. These results could explain the high activity and stability of PfNuc, suggesting its great potential applications in the industry and clinic.


Assuntos
Pseudomonas fluorescens , Pseudomonas fluorescens/genética , Simulação de Acoplamento Molecular , RNA , Endonucleases/genética , Escherichia coli/genética , DNA , Clonagem Molecular
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