Download a PDF containing pricing for our full product list. KanR and SpmR) were produced to generate a complete GB plasmid set. To facilitate the visualization of the design, we assigned each 4 bp cleavage sequence a different label: those produced by BsaI digestion are labeled with Arabic and Latin numbers (1,2,3, III, IV, etc). Among them, Golden Gate, a cloning system based on the use of Type IIS restriction enzymes, has a number of interesting features for operating at the level of genetic devices and modules , . Engler, C., Kandzia, R., and Marillonnet, S. (2008), Potapov, V. et. BbsI) would increase this figure up to 51%. Asterisks highlight those GB-assembled transcriptional units that were reused in the assembly of new multigenic structures. In parallel, single-assembled fluorescent proteins and p19 were also co-transformed in trans by mixing their respective Agrobacterium cultures. Samples were collected 5–6 days post-infiltration and examined for transgene expression. Les endonucléases de restriction de type IIS (par exemple, Fok I) clivent l'ADN à une distance définie de leurs sites de reconnaissance asymétriques non palindromiques; cette caractéristique est largement utilisée pour réaliser des techniques de clonage in vitro telles que le clonage Golden Gate . In a second example, we show the versatility of the system to assay recombinant antibody expression in a combinatorial way. For part domestication, internal sites are removed using standard methodology as overlapping-PCR, directed mutagenesis, or direct DNA synthesis. As with all Golden Gate-based methods, this system exploits the ability of Type IIS enzymes to cut outside their recognition site and permits DNA fragments with compatib… [11] using BsaI, BsmBI and BbsI as restriction enzymes in 25 cycle digestion/ligation reactions. Positive clones were selected in ampicillin-containing plates and confirmed by plasmid restriction analysis (EcoRI, NotI) and by sequencing. The inserts and cloning vectors are designed to place the Type IIS recognition site distal to the cleavage site, such that the Type IIS REase can remove the recognition sequence from the assembly. The restriction site is eliminated from the ligated product, so digestion and ligation can be carried out simultaneously. Next, two alternative “Identity Preservation” devices were considered: the previously described pEGB_C-DsRed-B conferring red fluorescence to the plant, and the newly constructed Rosea1, consisting of a 35S, Nos terminator and the Antirrhinum majus Rosea1 transcription factor that confers purple color to the cells [14]. As can be observed in Fig 4B, GoldenBraid assembled fluorescent proteins showed coordinated expression in N. benthamiana, as deduced by the similar fluorescence intensity observed in all three channels. There are no preconditions on the type of DNA pieces involved in the initial multipartite assembly, which can be either basic parts, transcriptional units or even small pathways. In the previous experiment with fluorescent proteins, parts were BsaI-assembled into level α plasmids (entry point α in Fig 3). One µl of the reaction was transformed into DH5α electrocompetent cells. Parts are ordinarily created by PCR amplification of suitable templates, adding appropriate BsaI extensions to the primers. A careful design of the assembly strategy will ensure in most cases that two pieces to be assembled are correctly positioned. Visit Type IIS Restriction Enzymes for a comprehensive list of all Type IIS enzymes available from NEB and their characteristics. In our approach, nucleotide boundaries were conveniently fixed to accommodate the nature/sequence of the different parts: site IV, defining PR-CDS boundary, was designed GATG, conveniently containing an ATG start codon, whereas site III, that forms CDS-TM boundary was designed to contain a TGA stop codon (namely TGAG). From here, the assembling of multigene structures was conducted as follows: the device pEGB_A-KanR-C was assembled to the IgA “therapeutic” module in a BsmBI reaction into pDGB_1AB3. Either as GB or as MoClo, the extension of Golden Gate method to the standardized assembly of higher order genetic pieces as devices and pathways is an important step that will facilitate genetic engineering, particularly in the plant field. This feature slows down the engineering process, this being apparently an obligate penalty for idempotency. Learn how to push the limits of your Golden Gate Assembly, and try one of our convenient kits (using BsmBI-v2 or BsaI-HFv2). https://doi.org/10.1371/journal.pone.0021622.g005. We think GoldenBraid has a number of characteristics that encourage its adoption by scientific community. Protein separation was carried out by SDS-PAGE on NuPAGE 10% Bis-Tris polyacrylamide gels (Invitrogen, Paisley, UK). BsmBI) in the backbone of the destination plasmid, so that BsaI-assembled devices (first order assembly) could similarly be assembled in second order destination plasmids. Performed the experiments: ASP EEF SIZ PJ. 4,7 sur 5 étoiles 5. Leaves were infiltrated with the four previous combinations. Place your order before 7:30pm EST for overnight delivery. Fill out our Technical Support Form, Given the indefinite design of GB, the obvious limitation to GB assemblies is that imposed by the maximum insert size that can be harbored by binary plasmids. Alternatively, level 1 can be branched into level 2-1i (intermediate) by adding an end-linker, yielding an open structure (albeit non functional), which can host new transcriptional units (level 2-2). NEB has developed convenient kits (using BsmBI-v2 and BsaI-HFv2) for performing Golden Gate Assembly. In this case, the double-device constructs were attempted by combining two independent single-device reactions (e.g. Gateway cloning, based on site-specific recombination, is a highly efficient cloning technique; however it leaves long scars between pieces (attB sites) and the reusability of pieces is limited. 23,95 € 23,95 € 9,99 € pour l'expédition. (C) GoldenBraid cloning strategy followed in the assembly of different IgA isotypes. Yes Ampicillin, kanamycin and spectinomycin were used for E. coli at 50 µg ml-1. Golden Gate uses type IIS restriction enzymes to generate four-nucleotide sticky ends flanking each DNA piece, which can be subsequently joined together efficiently by T4 ligase. al. Plant Synthetic Biology is a nascent discipline where the use of standard assembly rules has not yet rooted, and there is therefore room for efficient and innovative assembly methods to be adopted by the plant research community. Synthetic Biology requires efficient and versatile DNA assembly systems to facilitate the building of new genetic modules/pathways from basic DNA parts in a standardized way. This discipline aims at the design of artificial living forms displaying new traits not existing in nature [1], [2]. In a first example, using fluorescent proteins, it was demonstrated that GoldenBraid is permissive with the repetition of single pieces in multiple assemblies. (C) Representation of the four “twister” plasmids that can be eventually used to assist GoldenBraid cloning design. Plasmid DNA concentration was measured using a Nano Drop Spectrophotometer 2000 (Thermo Scientific). https://doi.org/10.1371/journal.pone.0021622.g001. Figure 2. In this sense GoldenBraid assembly is an attempt to extend the capabilities of the previously described Golden Gate cloning system to the requirements of Synthetic Biology. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Discover a faster, simpler path to publishing in a high-quality journal. Conceived and designed the experiments: ASP DO. In this way, GoldenBraid technology enables the standardization of Golden Gate for its use in Synthetic Biology. Beltrán and Cañas for helping us with barnase clones, and Dr. Darós for his assistance with fluorescent clones. : (i) GB makes use of only two restriction enzymes whereas MoClo requires a third enzyme and an additional selection cassette to ensure indefinite growth; (ii) GB pieces are fully reusable, whereas in MoClo intermediate structures need to be assembled to allow further growth of the construct; (iii) GB assemblies are always binary, whereas MoClo allows multipartite assemblies at level 2; (iv) the topology of MoClo system is basically lineal, with successive assembly levels and lateral branches corresponding to intermediate levels. A. Sarrion-Perdigones is a recipient of a FPI fellowship of the Spanish Ministry of Science and Innovation and P. Juárez is a recipient of a FPU fellowship from the Spanish Ministry of Education. Next, pEGB_A-YFP-C and pEGB_C-p19-B were assembled together into pDGB_1AB3, whereas pEGB_A-BFP-C and pEGB_C-DsRed-B were assembled into pDGB_3AB2, generating the expression vectors pEGB_1-YFP-p19-3 and pEGB_3-BFP-DsRed-2 respectively with the same high efficiency and accuracy. pD( ) is any plasmid (destination plasmid) hosting a LacZ cassette, such lacZ cassette flanked by two sites, as indicated by flanking numbers or letters. Golden-Gate sgRNA cloning protocol 1. (F) GoldenBraid strategy for the assembly of two alternative 5-gene T-DNA constructs. Leaf proteins were extracted in 3 volumes (v/w) of PBS (phosphate buffer saline, pH7.4). (2011) GoldenBraid: An Iterative Cloning System for Standardized Assembly of Reusable Genetic Modules. Yes In this top-down tinkering approach, the construction of new versions of an existing organism can be conducted following a modular hierarchical approach, by combining well defined basic DNA “parts” (e.g. The fragment-specific sequence of the overhangs allows orderly assembly of multiple fragments simultaneously. 15 – Applications of Restriction Enzymes, Restriction Enzymes in Golden Gate Assembly, Golden Gate Assembly Domestication Tutorial, Usage Guidelines for Golden Gate Assembly with PaqCI, Expanded “assembly standards” for MoClo, GoldenBraid2.0 and other modular Golden Gate Assembly methods, Technical Tips For Optimizing Golden Gate Assembly Reactions. (B) Spatial expression patterns of BFP, YFP and DsRed in N. benthamiana leaves agroinfiltrated with pEGB_A-YFP-P19-BFP-DsRed-C- (left captures, 1, 2 and 3) or with a mixture of the individual devices pEGB_A-YFP-C, pEGB_C-p19-B, pEGB_A-BFP-C and pEGB_C-DsRed-B (right captures 4, 5 and 6). By doing so, parts could be multi-partite assembled at any level by using an “extra” enzyme that does not destroy the restriction sites to be used at the next level. Level 2-1 hosts multipartite assembly of transcriptional units, yielding a non-reusable structure. GoldenBraid makes use of the multipartite Golden Gate cloning method to generate a modular assembly of standardized basic parts, which are then incorporated to a double loop (“braid”) cloning design that allows binary assembly of multipartite constructs. Restriction enzymes were purchased from New England Biolabs (Ipswich, USA). In this case a “therapeutic” module (anti-rotavirus IgA) initially aimed at transient expression is reused for a different purpose, the engineering of a biosafe plant biofactory for anti-rotavirus IgA. An overview of the GoldenGate Modular Cloning (MoClo) Assembly Standard. Golden Gate cloning or Golden Gate assembly is a molecular cloning method that allows a researcher to simultaneously and directionally assemble multiple DNA fragments into a single piece using Type IIs restriction enzymes and T4 DNA ligase. To substantiate this proposal we show here three examples of GoldenBraid-assisted multigene engineering in plants. Considering the simplicity and efficiency of helper-assisted twists, we tend to favor current design over a three-enzyme design. GoldenBraid assembly can be formally described with a simple system of four assembly rules: As deduced from these rules, in order to be GB-assembled together each DNA fragment needs to be cloned in a different plasmid from the same GB level. Encircled letters represent antibiotic resistance genes: A for AmpR, and K for KanR. Plasmid Mini Kit I (Omega Bio-Tek). here. HS lane contains control human serum. Lorsque vous utilisez Golden Gate clonage pour digérer le vecteur et ligaturer dans les oligonucléotides petits au sein d’une seule réaction simultanément, il est important de vérifier que le gRNA être clonés dans le vecteur n’a pas un site de BsmBI à l’intérieur, comme cela entraînera t gRNA il a été coupé et l’absence de colonies sur la transformation. Analyzed the data: ASP PJ AFdC AG DO. (D) Western Blot analysis of IgA transient expression in Nicotiana benthamiana. The advantages of such an arrangement are … Next, five-part BsmBI reactions were performed to assemble the individual heavy and light antibody chains. Moreover, at any time GB constructs can be added new pieces that facilitate its conversion to alternative assembling methods. Learn about our tools that are helping researchers develop diagnostics and vaccines for the SARS-CoV-2 virus. Multipartite assembly involved the combination of different basic parts each occupying a fixed position in the assembly (P1-P5). show the construction of a 33 Kb multigenic structure with the only use of successive Golden Gate reactions, a result that demonstrates that type IIS technologies (including GoldenBraid) can successfully be used for the assembly of complex genetic modules. Multigene engineering has an enormous potential in crop design, as for metabolic engineering, biofortification, molecular farming or for combination of traits of agronomic value via gene stacking [13]. A12D, D12C and C12B to obtain tripartite assemblies). The 56 plasmid GreenGate cloning kit can be used to create plant expression vectors containing several cassettes and generate multi-construct transgenic plants. https://doi.org/10.1371/journal.pone.0021622, Editor: Jean Peccoud, Virginia Tech, United States of America, Received: April 4, 2011; Accepted: June 3, 2011; Published: July 7, 2011. A number of additional techniques, based on site-specific recombination, the use of rare cutters or homing endonucleases have been developed [20]-[24], however in our opinion GoldenBraid compares favorably with most of them in terms of standardization, simplicity and reusability. Découvrez les outils proposés, notamment l'assemblage Gibson et le clonage Golden Gate, via Nature. Next, two alternative “biosafety” modules, namely pEGB_3-Barnase-Rosea-2 and pEGB_3-Barnase-DsRed-2 were assembled into level Ω plasmids as shown in Fig 4F. Plates (CORNING, New York, USA) were coated overnight with 10 ug/mL of recombinant VP8* in coating buffer (50 mM carbonate buffer pH 9,8) at 4°C. plant glyco-engineering or metabolic engineering, both approaches often relying on coordinated expression of the different transgenes in each cell [25]. Plasmid DNA preparations were obtained by using The E.Z.N.A. As the use of two enzymes limits the level of successive assembling levels to two, MoClo proposes the creation of intermediate assembly levels (2i-1, 2i-2, etc), where an “extra” piece (end-linker) consisting of a selection cassette (LacZ or Red) is introduced as a way to leave the assembly “open” to the addition of new pieces. However, in order to allow multipartite second order assemblies, this solution would require the design of a large number of destination plasmids, as the flanking BsmBI sites of the destination plasmids need to be different depending on the number of elements to be assembled in the second level. As a result, an expression plasmid (pEx) is created where all BsaI recognition sites have disappeared. promoters, coding sequences, terminators, etc.) A simple solution to this limitation, described here as GoldenBraid, is to insert a loop (braid) in the cloning design, so that the expression plasmids from first level become entry plasmids for second level assemblies and vice versa. This objective can be pursued following a bottom-up strategy, by creating new living forms from its basic components; however, a more straightforward option consists of integrating new genetic circuits within the genome of a current living organism or “chassis”. PCR fragments were purified and subsequently GB-cloned in each of the four destination plasmids. This feature is particularly important when DNA fragments comprise coding sequences for sensitive applications (e.g. The Golden Gate method uses Type IIs restriction enzymes in combination with DNA ligase. Despite being based on restriction/ligation, its all-in-one-tube design avoids inconvenient gel extraction procedures that often reduce cloning efficiency; most interestingly, it allows seamless assembly by careful design of the restriction sites. “Comprehensive Profiling of Four Base Overhang Ligation Fidelity by T4 DNA Ligase and Application to DNA Assembly.”. international site. Recently, NEB has published research on T4 DNA Ligase Fidelity (9) . ! We propose the use of GoldenBraid as an assembly standard for Plant Synthetic Biology. Two of the resulting devices (YFP and BFP transcriptional units) were assembled into pDGB_A12C and the two others (DsRed and p19 transcriptional units) were assembled into pDGB_C12B, generating four expression vectors: pEGB_A-YFP-C, pEGB_A-BFP-C, pEGB_C-p19-B and pEGB_C-DsRed-B. Affiliation Numbers 1, 2, and 3 are four-nucleotide sequences, which flank (X) pieces, and which are made protuberant ends upon BsaI digestion. Here we present GoldenBraid, a new modular assembly system that allows the binary combination of multipartite assemblies using an extremely simple set of rules, very close to idempotency. Le 21 février 2019 à 17:14:11 enjokosai a écrit : - page 12 - Topic La technologie stagne j'ai l'impression du 21-02-2019 15:35:36 sur les forums de jeuxvideo.com Le dernier vecteur pBS peut être assemblé en une semaine à partir de quatre entrées grâce au clonage efficace de Golden Gate. Finally a male sterility “device” was constructed, combining barnase-barstar CDS under pTA29 anther-specific promoter [15], [16]. Further additions will involve the exchange of lacZ and Red cassettes by new “true” pieces in successive assembly levels. PLOS ONE promises fair, rigorous peer review, As a result the two functional devices were assembled in one T-DNA (pEGB_3-BFP-DsRed-2) with 1/10 efficiency of the two-step assembly, but in a single day experiment and without requiring intermediate E.coli transformation. All the components in the GoldenBraid system were made free of internal BsaI and BsmBI sites. This may include, among other elements, attB cassettes for Gateway cloning, overlapping regions for in vitro or in vivo recombination, or recombination sites (e.g. Agrobacterium-mediated transient gene expression (agroinfiltration) in Nicotiana benthamiana is an efficient technology for recombinant protein production in plants. This final multigenic construction pEGB_A-YFP-P19-BFP-DsRed-C, comprising 11.4 Kb and 12 parts, was functionally validated by agroinfiltration into N. benthamiana leaves. Also, similarly to GB, MoClo proposes the use of a second enzyme in destination plasmids as a way to extend Golden Gate cloning to a second assembly level. They also differ in the resistance marker associated to each of them, allowing counterselection. 2. Moreover, this is achieved with a small toolbox consisting of only four destination plasmids and a limited number of assembly rules. Golden Gate cloning requires that the DNA fragments and recipient vector conform to specific requirements, such as the presence of type IIS enzyme restriction sites at the ends of the fragments and vector, and a lack of the same restriction sites in internal sequences of the fragments and vector. Oppositely, multipartite systems have been developed allowing the assembly of multiple DNA fragments in a single step. For the detection of IgH_α1 and α2 heavy chains membranes were incubated with 1∶20000 Anti-Human IgA (α-chain specific) peroxidase conjugate (SIGMA, St. Louis, USA); the Igλ and Igk light chains were detected by incubation with 1∶10000 Anti-Human lambda light chain (Sigma) and 1∶10000 anti-human-kappa chain (Pierce - Thermo Scientific) as primary antibodies, followed by an incubation with 1∶10000 ECL Rabbit IgG, HRP-Linked (GE Healthcare) and 1∶10000 Anti-Goat IgG-peroxidase (Sigma) respectively, as secondary antibodies. Amplified parts were TA Cloned using the pGEM®-T Easy Vector System (Promega, Madison, USA) and 1 µl of the ligation was transformed into DH5α electrocompetent cells. transcriptional units), those devices into basic genetic modules (e.g. The remaining boundaries were designed to produce benign junctions within coding sequences. This kit consists of one 96-well plate, and will be shipped as bacterial glycerol stocks on dry ice. With some adaptations, domestication of pDGB plasmids was performed basically as earlier described by Engler et al. … Yes However at this point the solutions provided by MoClo and GB to achieve the indefinite growth of multigene structures become completely different. Here we present GoldenBraid (GB), a standardized assembly system based on type IIS restriction enzymes that allows the indefinite growth of reusable gene modules made of standardized DNA pieces. Inoculations were carried out by syringe-agroinfiltration in leaves of 4–5 weeks old Nicotiana benthamiana plants (growing conditions: 24°C day/20°C night in a 16 h light/8 h dark cycle). To test whether an in cis co-transformation approach outperforms the in trans approach, three different fluorescent devices were GB-assembled and its performance compared with that of an in trans approach. here. Golden Gate Cloning overcomes this restriction by exploiting the ability of type IIs restriction enzymes (such as BsaI, BsmBI or BbsI) to produce 4 bp sticky ends right next to their binding sites, irrespective of the adjacent nucleotide sequence. A comparison of the topology of the two systems can be observed in Fig 5. No, Is the Subject Area "Synthetic biology" applicable to this article? These enzymes digest DNA at a defined distance few nucleotides away from its recognition site, not requiring any specific sequence in the actual cleavage site, and often leaving a short overhang. No, Is the Subject Area "DNA transcription" applicable to this article? A versatile strategy was designed to assemble any desired human IgA (h_IgA) isotype. In the light of the results showed here, GB-assisted assembling would improve the outcome of these transient approaches, as it would do so if the same engineered T-DNAs were to be stably transformed in plants. At least as long as transient expression is concern, the introduction of 4 copies of 35S promoter in a single T-DNA does not affect the transient expression of the fluorescent proteins. In view of this need, we have adapted GoldenBraid scheme to plant biotechnology by domesticating four binary plasmids, and demonstrated in a number of examples the feasibility of the methodology. In a final example we demonstrate the reusability of GB constructs with the assembly of two alternative constructs comprising five transcriptional units. Paris 2013 - 2013 microbiologie, PCR, clonage golden gate,transformation bactérienne, agroinfection, western blot, localisation subcellulaire de protéines recombinantes. A. Les méthodes d’assemblages par clonage modulaire de type « Golden gate » utilisent les enzymes de restriction de type IIS et permettent l’assemblage d’au plus dix répétitions orientées en une seule étape de ligation, … The plant-based production of therapeutic antibodies is a field that requires flexible multigene cloning strategies. To facilitate the interpretation, we gave a label to each 4 bp cleavage site producing the corresponding overhang (e.g. Positive clones were selected in kanamycin or spectinomycin-containing plates. A third comparative advantage is accuracy: Type IIS cloning allows the building of assemblies containing short “benign” seams, as earlier demonstrated in Golden Gate cloning. It is highly desirable that all the components in the GoldenBraid system are free of internal BsaI and BsmBI sites. Please sign back in to continue your session. VIDÉO. The inserts and cloning vectors are designed to place the Type IIS recognition site distal to the cleavage site, such that the Type IIS REase can remove the recognition sequence from the assembly. Achieving near zero-downtime upgrade requires cloning the source database, which is an image copy of the database at a timestamp referred to as the System Change Number (SCN). (B) Two transcriptional units assembled in complementary α plasmids can be reused as entry vectors (pEGB) for a subsequent level Ω binary assembly, provided that they share a BsmBI sticky end (labeled as encircled C). Synthetic Biology adapts the general engineering principle of assembling standard components, dating back to the Industrial Revolution, to biological components. Is the Subject Area "Cloning" applicable to this article? Biologie moléculaire: PCR, RT-PCR, qPCR, clonage (golden gate/gateway), surexpression de gène, extraction ADN/ARN, transformation Biologie végétale: phénotypage de lignées mutantes, culture in-vitro, régénération de… 1) Implication de ERF A3 dans la maturation de la tomate. Despite its obvious advantages, Golden Gate, as many multipartite systems, is limited in standardization and reusability. Escherichia coli DH5α was used for gene cloning and Agrobacterium tumefaciens strain GV3101 was used for plant agroinfiltration and transformation experiments. In an attempt to facilitate versatile cloning into plant binary vectors, we and others have developed plasmid collections based on Gateway technology [17], [18], [19]. Usually, basic pieces involve the lacZ cassette, antibiotic resistance, and two additional pieces containing replication origins and each of the T-DNA borders. Therefore, Type IIS REases that create 4-base overhangs (such as BsaI-HF®v2, BbsI/BbsI-HF, BsmBI-v2 and Esp3I) are preferred. Both groups of features are probably mutually exclusive: MoClo multipartite assemblies at level 2 come at the expenses of the incorporation of a number of additional destination plasmids and end-linker plasmids to the system, which further increases its complexity. For this goal, IgA “therapeutic” module is combined with a “selection” device for plant stable transformation (KanR) and two alternative biosafety modules, both comprising an “identity preservation” device and a “polen-sterility” device. Plant genetic engineering currently relies on assembly methodologies poorly adaptable to Synthetic Biology. No PCR amplification or further modifications of the piece are required. No, Is the Subject Area "Genetic engineering" applicable to this article? email or call 1-800-NEB-LABS. The loop design of GoldenBraid system should allow the use of both level α and level Ω plasmids for multipartite assembly of basic parts. Save time and money by placing an order with NEB. Nevertheless, the newly assembled transcriptional unit (TU1, represented for simplification as an arrow) remains flanked by BsmBI cleavable sites (represented as encircled capital letters). No, Is the Subject Area "Bioengineering" applicable to this article? Le clonage moléculaire consiste à produire des molécules dADN recombinant et à les utiliser pour transformer un organisme hôte, dans lequel elles sont répliquées. The advantages of such an arrangement are three-fold: The net result is the ordered and seamless assembly of DNA fragments in one reaction. Rifampicin, tetracycline and gentamicin were also used for A.tumefaciens at 50, 12.5 and 30 µg ml−1 respectively. Les inserts et les vecteurs de clonage sont conçus de façon à placer le site de reconnaissance à l’extrémité distale du site de clivage, afin que l’endonucléase de restriction de type IIS puisse éliminer la séquence de … Adding products to your cart without being signed in will result in a loss of your cart when you do sign in or leave the site. The GB system consists of a set of four destination plasmids (pDGBs) designed to incorporate multipartite assemblies made of standard DNA parts and to combine them binarily to build increasingly complex multigene constructs.