Name: principles of site-specific recombinase (ssr) technology
Uploaded: 2008-05-29T12:11:00
Description: Watch this Scientific Journal Video about Principles of Site-Specific Recombinase SSR Technology at JoVE.com

principles of site-specific recombinase (ssr) technology

部位特異的リコンビナーゼ（SSR）技術は、遺伝子の構造の操作は、遺伝子機能を探索することができますし、分子生物学の不可欠なツールとなっています。サイト固有のリコンビナーゼは異なるDNAの標的配列に結合するタンパク質です。のCre / LOXシステムは最初に1980年代にバクテリオファージに記載されていた。 Creリコンビナーゼは、2つのloxP（X -オーバーP1の軌跡）サイト間でDNAの部位特異的組換えを触媒するタイプIトポイソメラーゼです。のCre / LOXシステムは補助因子を必要としません。 loxP配列は、組換えや再配置が行われる方向コア配列を囲むのCREリコンビナーゼのための別個の結合部位が含まれています。細胞がloxP部位部位を含有し、Creリコンビナーゼを表現するときに、組換えイベントが発生します。二本鎖DNAは、Creリコンビナーゼにより両方つのloxP部位で切断再配置、および（&quot;はさみと糊&quot;）連結されている。組換え事象の製品は、非対称のシーケンスの相対的な向きに依存する。 SSR技術は頻繁に遺伝子機能を探索するためのツールと​​して使用されます。ここに目的の遺伝子がCreを標的部位loxP部位（&quot;floxed&quot;）と並んでいる。動物は、組織特異的プロモーターの制御下にCreリコンビナーゼを発現している動物と交配されています。 Creリコンビナーゼを表現する組織では、標的配列に結合し、floxed遺伝子を消費税。制御された遺伝子の欠失は、特定の組織内および異なる時点での遺伝子機能の調査を可能にします。 SSRテクノロジー---条件付き変異導入を用いて遺伝子機能の解析 - 遺伝子の欠失が頻繁に致命的である伝統的なノックアウト比べて大きな利点があります。

Watch this Scientific Journal Video about Principles of Site-Specific Recombinase SSR Technology at JoVE.com

Principles of Site-Specific Recombinase SSR Technology

部位特異的リコンビナーゼ（SSR）技術とCre / LOX系の出現は、分子生物学における数々の進歩につながっている、そしてトランスジェニック動物での遺伝子機能を評価するための貴重なツールとしての地位を証明しています。このインタビューでは、環化リコンビナーゼ（Cre）を、どのようにこの酵素の使用は、戦略より伝統的なノックアウト比べて大きな利点を持っている条件付き変異誘発、の開発につながっていることにより部位特異的組換えのメカニズムについて説明します。

部位特異的リコンビナーゼ（SSR）技術の原理

Site-specific recombinase (SSR) technology allows the manipulation of gene structure to explore gene function and has become an integral tool of molecular ...

principles-of-site-specific-recombinase-ssr-technology

Research

JoVE Journal

Biology

Principles of Site-Specific Recombinase (SSR) Technology

Molecular Evolution of the Tre Recombinase

Here we report the generation of Tre recombinase through directed, molecular evolution. Tre recombinase recognizes a pre-defined target sequence within the LTR sequences of the HIV-1 provirus, resulting in the excision and eradication of the provirus from infected human cells. 
We started with Cre, a 38-kDa recombinase, that recognizes a 34-bp double-stranded DNA sequence known as loxP. Because Cre can effectively eliminate genomic sequences, we set out to tailor a recombinase that could remove the sequence between the 5'-LTR and 3'-LTR of an integrated HIV-1 provirus. As a first step we identified sequences within the LTR sites that were similar to loxP and tested for recombination activity. Initially Cre and mutagenized Cre libraries failed to recombine the chosen loxLTR sites of the HIV-1 provirus. As the start of any directed molecular evolution process requires at least residual activity, the original asymmetric loxLTR sequences were split into subsets and tested again for recombination activity. Acting as intermediates, recombination activity was shown with the subsets. Next, recombinase libraries were enriched through reiterative evolution cycles. Subsequently, enriched libraries were shuffled and recombined. The combination of different mutations proved synergistic and recombinases were created that were able to recombine loxLTR1 and loxLTR2. This was evidence that an evolutionary strategy through intermediates can be successful. After a total of 126 evolution cycles individual recombinases were functionally and structurally analyzed. The most active recombinase -- Tre -- had 19 amino acid changes as compared to Cre. Tre recombinase was able to excise the HIV-1 provirus from the genome HIV-1 infected HeLa cells (see "HIV-1 Proviral DNA Excision Using an Evolved Recombinase", Hauber J., Heinrich-Pette-Institute for Experimental Virology and Immunology, Hamburg, Germany). While still in its infancy, directed molecular evolution will allow the creation of custom enzymes that will serve as tools of "molecular surgery" and molecular medicine.

Here we report the generation of Tre recombinase through directed, molecular evolution. Tre recombinase recognizes a pre-defined target sequence within the LTR sequences of the HIV-1 provirus, resulting in the excision and eradication of the provirus from infected human cells. While still in its infancy, directed molecular evolution will allow the creation of custom enzymes that will serve as tools of molecular surgery and molecular medicine.

トレリコンビナーゼの分子進化

Here we report the generation of Tre recombinase through directed, molecular evolution. Tre recombinase recognizes a pre-defined target sequence within ...

生物学

Interview: HIV-1 Proviral DNA Excision Using an Evolved Recombinase

HIV-1 integrates into the host chromosome of infected cells and persists as a provirus flanked by long terminal repeats. Current treatment strategies primarily target virus enzymes or virus-cell fusion, suppressing the viral life cycle without eradicating the infection. Since the integrated provirus is not targeted by these approaches, new resistant strains of HIV-1 may emerge. Here, we report that the engineered recombinase Tre (see Molecular evolution of the Tre recombinase , Buchholz, F., Max Planck Institute for Cell Biology and Genetics, Dresden) efficiently excises integrated HIV-1 proviral DNA from the genome of infected cells. We produced loxLTR containing viral pseudotypes and infected HeLa cells to examine whether Tre recombinase can excise the provirus from the genome of HIV-1 infected human cells. A virus particle-releasing cell line was cloned and transfected with a plasmid expressing Tre or with a parental control vector. Recombinase activity and virus production were monitored. All assays demonstrated the efficient deletion of the provirus from infected cells without visible cytotoxic effects. These results serve as proof of principle that it is possible to evolve a recombinase to specifically target an HIV-1 LTR and that this recombinase is capable of excising the HIV-1 provirus from the genome of HIV-1-infected human cells.
Before an engineered recombinase could enter the therapeutic arena, however, significant obstacles need to be overcome. Among the most critical issues, that we face, are an efficient and safe delivery to targeted cells and the absence of side effects.

Current HIV-1 strategies act to suppress the viral life cycle but do not effectively eradicate infection. Here, we demonstrate that an engineered recombinase can efficiently excise integrated HIV-1 proviral DNA from the genome of infected cells.

インタビュー：進化リコンビナーゼを用いたHIV - 1プロウイルスDNAの切り出し

HIV-1 integrates into the host chromosome of infected cells and persists as a provirus flanked by long terminal repeats. Current treatment strategies ...

Closed System Cell Culture Protocol Using HYPERStack Vessels with Gas Permeable Material Technology

Large volume adherent cell culture is currently standardized on stacked plate cell growth products when microcarrier beads are not an optimal choice. HYPERStack vessels allow closed system scale up from the current stacked plate products and delivers >2.5X more cells in the same volumetric footprint. The HYPERStack vessels function via gas permeable material which allows gas exchange to occur, therefore eliminating the need for internal headspace within a vessel. The elimination of headspace allows the compartment where cell growth occurs to be minimized to reduce space, allowing more layers of cell growth surface area within the same volumetric footprint.
For many applications such as cell therapy or vaccine production, a closed system is required for cell growth and harvesting. The HYPERStack vessel allows cell and reagent addition and removal via tubing from media bags or other methods.
This protocol will explain the technology behind the gas permeable material used in the HYPERStack vessels, gas diffusion results to meet the metabolic needs of cells, closed system cell growth protocols, and various harvesting methods.

An Introduction into the technology, protocol and handling of the Corning HYPERStack Vessels and accessories used for high yield adherent cell culture. The protocol will show how to use the closed system vessels for increasing cell harvesting over current stacked plate products.

ガス透過性材料技術とHYPERStackの船舶を使用するクローズドシステムの細胞培養のプロトコル

Large volume adherent cell culture is currently standardized on stacked plate cell growth products when microcarrier beads are not an optimal choice.   ...

Principles of Rodent Surgery for the New Surgeon

For both scientific and animal welfare reasons, training in basic surgical concepts and techniques should be undertaken before ever seeking to perform surgery on a rodent. Students, post-doctoral scholars, and others interested in performing surgery on rodents as part of a research protocol may not have had formal surgical training as part of their required coursework. Surgery itself is a technical skill, and one that will improve with practice. The principles of aseptic technique, however, often remain unexplained or untaught. For most new surgeons, this vital information is presented in piecemeal fashion or learned on the job, neither of which is ideal. It may also make learning how to perform a particular surgery difficult, as the new surgeon is learning both a surgical technique and the principles of asepsis at the same time. This article summarizes and makes recommendations for basic surgical skills and techniques necessary for successful rodent surgery. This article is designed to supplement hands-on training by the user's institution.

Before attempting surgery, a new surgeon should have training in basic surgical techniques and concepts. This article will present basic surgical considerations with an emphasis on rodents.

新外科医のための齧歯類の外科の原則

For both scientific and animal welfare reasons, training in basic surgical concepts and techniques should be undertaken before ever seeking to perform ...

Discovering Protein Interactions and Characterizing Protein Function Using HaloTag Technology

Research in proteomics has exploded in recent years with advances in mass spectrometry capabilities that have led to the characterization of numerous proteomes, including those from viruses, bacteria, and yeast.&#160; In comparison, analysis of the human proteome lags behind, partially due to the sheer number of proteins which must be studied, but also the complexity of networks and interactions these present. To specifically address the challenges of understanding the human proteome, we have developed HaloTag technology for protein isolation, particularly strong for isolation of multiprotein complexes and allowing more efficient capture of weak or transient interactions and/or proteins in low abundance. &#160;HaloTag is a genetically encoded protein fusion tag, designed for covalent, specific, and rapid immobilization or labelling of proteins with various ligands. Leveraging these properties, numerous applications for mammalian cells were developed to characterize protein function and here we present methodologies including: protein pull-downs used for discovery of novel interactions or functional assays, and cellular localization. We find significant advantages in the speed, specificity, and covalent capture of fusion proteins to surfaces for proteomic analysis as compared to other traditional non-covalent approaches. We demonstrate these and the broad utility of the technology using two important epigenetic proteins as examples, the human bromodomain protein BRD4, and histone deacetylase HDAC1.&#160; These examples demonstrate the power of this technology in enabling &#160;the discovery of novel interactions and characterizing cellular localization in eukaryotes, which will together further understanding of human functional proteomics. &#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;

HaloTag technology is a multifunctional technology which has shown significant success in isolation of both small and large protein complexes from mammalian cells.&#160; Here we highlight the advantages of this technology compared to existing alternatives and demonstrate its utility to study numerous aspects of protein function inside eukaryotic cells.

タンパク質相互作用を発見したHaloTag技術を用いたタンパク質機能の特性評価

Research in proteomics has exploded in recent years with advances in mass spectrometry capabilities that have led to the characterization of numerous ...

Reduced-gravity Environment Hardware Demonstrations of a Prototype Miniaturized Flow Cytometer and Companion Microfluidic Mixing Technology

Until recently, astronaut blood samples were collected in-flight, transported to earth on the Space Shuttle, and analyzed in terrestrial laboratories. If humans are to travel beyond low Earth orbit, a transition towards space-ready, point-of-care (POC) testing is required. Such testing needs to be comprehensive, easy to perform in a reduced-gravity environment, and unaffected by the stresses of launch and spaceflight. Countless POC devices have been developed to mimic laboratory scale counterparts, but most have narrow applications and few have demonstrable use in an in-flight, reduced-gravity environment. In fact, demonstrations of biomedical diagnostics in reduced gravity are limited altogether, making component choice and certain logistical challenges difficult to approach when seeking to test new technology. To help fill the void, we are presenting a modular method for the construction and operation of a prototype blood diagnostic device and its associated parabolic flight test rig that meet the standards for flight-testing onboard a parabolic flight, reduced-gravity aircraft. The method first focuses on rig assembly for in-flight, reduced-gravity testing of a flow cytometer and a companion microfluidic mixing chip. Components are adaptable to other designs and some custom components, such as a microvolume sample loader and the micromixer may be of particular interest. The method then shifts focus to flight preparation, by offering guidelines and suggestions to prepare for a successful flight test with regard to user training, development of a standard operating procedure (SOP), and other issues. Finally, in-flight experimental procedures specific to our demonstrations are described.

Spaceflight blood diagnostics need innovation. Few demonstrations have been published illustrating in-flight, reduced-gravity health diagnostic technology. Here we present a method for construction and operation of a parabolic flight test rig for a prototype point-of-care flow-cytometry design, with components and preparation strategies adaptable to other setups.

プロトタイプ小型化フローサイトメーターおよびコンパニオンマイクロ流体混合技術の縮小重力環境ハードウェアデモンストレーション

Until recently, astronaut blood samples were collected in-flight, transported to earth on the Space Shuttle, and analyzed in terrestrial laboratories. If ...

Development of a Quantitative Recombinase Polymerase Amplification Assay with an Internal Positive Control

It was recently demonstrated that recombinase polymerase amplification (RPA), an isothermal amplification platform for pathogen detection, may be used to quantify DNA sample concentration using a standard curve. In this manuscript, a detailed protocol for developing and implementing a real-time quantitative recombinase polymerase amplification assay (qRPA assay) is provided. Using HIV-1 DNA quantification as an example, the assembly of real-time RPA reactions, the design of an internal positive control (IPC) sequence, and co-amplification of the IPC and target of interest are all described. Instructions and data processing scripts for the construction of a standard curve using data from multiple experiments are provided, which may be used to predict the concentration of unknown samples or assess the performance of the assay. Finally, an alternative method for collecting real-time fluorescence data with a microscope and a stage heater as a step towards developing a point-of-care qRPA assay is described. The protocol and scripts provided may be used for the development of a qRPA assay for any DNA target of interest.

Provided is a protocol for developing a real-time recombinase polymerase amplification assay to quantify initial concentration of DNA samples using either a thermal cycler or a microscope and stage heater. Also described is the development of an internal positive control. Scripts are provided for processing raw real-time fluorescence data.

内部陽性対照との定量的リコンビナーゼポリメラーゼ増幅アッセイの開発

It was recently demonstrated that recombinase polymerase amplification (RPA), an isothermal amplification platform for pathogen detection, may be used to ...

Inducing a Site Specific Replication Blockage in E. coli Using a Fluorescent Repressor Operator System

Obstacles present on DNA, including tightly-bound proteins and various lesions, can severely inhibit the progression of the cell&#39;s replication machinery. The stalling of a replisome can lead to its dissociation from the chromosome, either in part or its entirety, leading to the collapse of the replication fork. The recovery from this collapse is a necessity for the cell to accurately complete chromosomal duplication and subsequently divide. Therefore, when the collapse occurs, the cell has evolved diverse mechanisms that take place to restore the DNA fork and allow replication to be completed with high fidelity. Previously, these replication repair pathways in bacteria have been studied using UV damage, which has the disadvantage of not being localized to a known site. This manuscript describes a system utilizing a Fluorescence Repressor Operator System (FROS) to create a site-specific protein block that can induce the stalling and collapse of replication forks in Escherichia coli. Protocols detail how the status of replication can be visualized in single living cells using fluorescence microscopy and DNA replication intermediates can be analyzed by 2-dimensional agarose gel electrophoresis. Temperature sensitive mutants of replisome components (e.g. DnaBts) can be incorporated into the system to induce a synchronous collapse of the replication forks. Furthermore, the roles of the recombination proteins and helicases that are involved in these processes can be studied using genetic knockouts within this system.

Inducing a Site Specific Replication Blockage in E. coli Using a Fluorescent Repressor Operator System

We describe here a system utilizing a site-specific, reversible in vivo protein block to stall and collapse replication forks in Escherichia coli. The establishment of the replication block is evaluated by fluorescence microscopy and neutral-neutral 2-dimensional agarose gel electrophoresis is used to visualize replication intermediates.

サイトを誘導する具体的なレプリケーション閉塞中<i&gt; E。大腸菌</i&gt;蛍光プレッサーオペレータシステムの使用

Obstacles present on DNA, including tightly-bound proteins and various lesions, can severely inhibit the progression of the cell&#39;s replication ...

Quantification of Site-specific Protein Lysine Acetylation and Succinylation Stoichiometry Using Data-independent Acquisition Mass Spectrometry

Post-translational modification (PTM) of protein lysine residues by N&#400;-acylation induces structural changes that can dynamically regulate protein functions, for example, by changing enzymatic activity or by mediating interactions. Precise quantification of site-specific protein acylation occupancy, or stoichiometry, is essential for understanding the functional consequences of both global low-level stoichiometry and individual high-level acylation stoichiometry of specific lysine residues. Other groups have reported measurement of lysine acetylation stoichiometry by comparing the ratio of peptide precursor isotopes from endogenous, natural abundance acylation and exogenous, heavy isotope-labeled acylation introduced after quantitative chemical acetylation of proteins using stable isotope-labeled acetic anhydride. This protocol describes an optimized approach featuring several improvements, including: (1) increased chemical acylation efficiency, (2) the ability to measure protein succinylation in addition to acetylation, and (3) improved quantitative accuracy due to reduced interferences using fragment ion quantification from data-independent acquisitions (DIA) instead of precursor ion signal from data-dependent acquisition (DDA). The use of extracted peak areas from fragment ions for quantification also uniquely enables differentiation of site-level acylation stoichiometry from proteolytic peptides containing more than one lysine residue, which is not possible using precursor ion signals for quantification. Data visualization in Skyline, an open source quantitative proteomics environment, allows for convenient data inspection and review. Together, this workflow offers unbiased, precise, and accurate quantification of site-specific lysine acetylation and succinylation occupancy of an entire proteome, which may reveal and prioritize biologically relevant acylation sites.

Here, we present unbiased quantification of site-specific protein acetylation and/or succinylation occupancy (stoichiometry) of an entire proteome through a ratiometric analysis of endogenous modifications to modifications introduced after quantitative chemical acylation using stable isotope-labeled anhydrides. In combination with sensitive data-independent acquisition mass spectrometry, accurate site occupancy measurements are obtained.

部位特異的タンパク質のリジンのアセチル化のサクシニル化化学量論組成データに依存しない取得質量分析法による定量

Post-translational modification (PTM) of protein lysine residues by N&#400;-acylation induces structural changes that can dynamically regulate protein ...

Parallel High Throughput Single Molecule Kinetic Assay for Site-Specific DNA Cleavage

Site-specific DNA cleavage (SSDC) is a key step in many cellular processes, and it is crucial to gene editing. This work describes a kinetic assay capable of measuring SSDC in many single DNA molecules simultaneously. Bead-tethered substrate DNAs, each containing a single copy of the target sequence, are prepared in a microfluidic flow channel. An external magnet applies a weak force to the paramagnetic beads. The integrity of up to 1,000 individual DNAs can be monitored by visualizing the microbeads under darkfield imaging using a wide-field, low magnification objective. Injecting of a restriction endonuclease, NdeI, initiates the cleavage reaction. Video microscopy is used to record the exact moment of each DNA cleavage by observing the frame in which the associated bead moves up and out of the focal plane of the objective. Frame-by-frame bead counting quantifies the reaction, and an exponential fit determines the reaction rate. This method allows collection of quantitative and statistically significant data on single molecule SSDC reactions in a single experiment.

A highly parallel method for measuring the site-specific cleavage of DNA at the single molecule level is described. This protocol demonstrates the technique using the restriction endonuclease NdeI. The method can easily be modified to study any process that results in site-specific DNA cleavage.

部位特異的DNA切断のための並列高スループット単一分子運動アッセイ

Site-specific DNA cleavage (SSDC) is a key step in many cellular processes, and it is crucial to gene editing. This work describes a kinetic assay capable ...