Invitrogen GeneArt Strings DNA Fragments are custom-made, uncloned, double-stranded linear DNA fragments assembled from synthetic oligonucleotides. They are ideal for multi-fragment assembly with our GeneArt Gibson Assembly® cloning Kits and low error rates mean less screening for the correct, full-length sequence.
All Strings DNA Fragments can be optimized for protein expression at no extra cost and are also available as Strings DNA Libraries.
Ordering Strings DNA Fragments
The new GeneArt Services Dashboard makes it easy to order
- Configure projects, track order status, and get support all in one location
- Easily fix complex sequences with minimal changes
- Full optimization available for improved protein expression
- Free shipping for Strings DNA Fragments
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Download the sequence submission form for email ordering
Reasons to choose Strings DNA Fragments
Strings DNA Fragments are assembled from synthetic oligonucleotides using the same high-quality process developed for GeneArt Gene Synthesis Clones and are delivered dried and ready for resuspension, cloning, and screening for identification of the correct sequence. They are delivered in a tube format and are a fast and smart alternative for getting your synthetic gene cloned into your expression plasmid.
The proprietary Invitrogen GeneOptimizer algorithm provides significant gains in downstream protein expression compared to wild-type sequences and there are no additional adaptors to remove.
Strings DNA Fragments are:
- Affordable—GeneArt Strings DNA fragments are a cost-effective alternative to doing your own PCR or purchasing fully cloned genes
- Flexible—Sequence design flexibility with no adapters to worry about; use any downstream cloning method
- Fast—Improved turnaround times; at least 200 ng of GeneArt Strings DNA Fragments are produced in as little as 3–4 business days
- Optimized—Use our GeneArt GeneOptimizer software to improve downstream mRNA stability and increase protein expression by up to 15-fold over wild type
- Quality—Low error rates of <1:5,000 bp mean you screen fewer colonies to find the correct clone
New to GeneArt services? Explore GeneArt Dashboard quick guides
| Fragment range (bp) | Production time (business days)* |
|---|---|
| 200–1,000 | 3–5 |
| 1,001–3,000 | 4–6 |
| DNA Libraries: IUPAC mixed bases | 10–15 |
*Production time is the number of business days required to synthesize GeneArt Strings DNA products in our manufacturing facility. Delivery time is in addition to production time and depends on the destination of the shipment.
Using DNA Strings: application data
GeneArt Gibson Assembly cloning kits
One, two, and three Strings DNA fragments of 1 kb were assembled using the GeneArt Gibson Assembly HiFi Cloning Kit in pcDNA 3.4 vector using Invitrogen TOP10 competent cells.
GeneArt Gibson Assembly HiFi kits provide high cloning efficiency using single- to multiple-insert designs.
Restriction enzyme cloning example
Eight Strings DNA Fragments up to 3,000 bp were cloned using 5’ AscI restriction enzymes and 3’ PacI restriction enzymes. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Eight (<1 kb) or 16 (>1 kb) colonies were picked, and colony PCR was performed to identify full-length clones; four to eight full-length clones were sequenced to determine the number of sequence-correct clones.
The percentage of clones with correct length as identified by colony PCR (cloning efficiency) and the percent of sequence-correct clones (fidelity) based on the number of full-length clones.
GeneArt type IIs assembly example
Eight Strings DNA Fragments of different lengths up to 2,800 bp with suitable sequence ends (AarI recognition sequence and 6 bp stuffer nucleotides) were used for direct assembly with the GeneArt Type IIs Assembly Kit, Aar I. The resulting four genes were 5,056 bp, 5,061 bp, 5,267 bp, and 5,448 bp long. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Sixteen colonies were picked, and colony PCR was performed to identify full-length clones. For all four assembled genes, eight colonies were sequenced to determine the number of sequence-correct clones.
The percentage of clones with correct length as identified by colony PCR (cloning efficiency) and the percent of sequence-correct clones (fidelity) based on the number of full-length clones.
GeneArt seamless cloning example
Ten Strings DNA Fragments up to 3,000 bp were cloned using the GeneArt Seamless Cloning and Assembly Kit. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Eight (<1 kb) or 16 (>1 kb) colonies were picked, and colony PCR was performed to identify full-length clones; four to eight full-length clones were sequenced to determine the number of sequence-correct clones.
The percentage of clones with correct length as identified by colony PCR (cloning efficiency) and the percent of sequence-correct clones (fidelity) based on the number of full-length clones.
While Strings DNA Fragments are offered in lengths up to 3,000 bp, GeneArt Seamless assembly technology can be used to directly assemble two Strings DNA Fragments up to 1 kb without pre-cloning of the subfragments.
If you want to assemble more Strings DNA Fragments or longer Strings DNA Fragments using seamless assembly technology, pre-cloning of the subfragments is recommended to limit post-assembly screening efforts necessary for finding correct clones. Alternatively, you can use GeneArt Type IIs assembly technology.
Here, twelve Strings DNA fragments of different lengths up to 1 kb with suitable sequence ends (15 bp homology to the vector or to the next fragment) were used for direct assembly with the GeneArt Seamless Cloning and Assembly Kit. The resulting six genes were 1,375 bp, 1,466 bp, 1,536 bp, 1,590 bp, 1,647 bp, and 1,853 bp long. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Sixteen colonies were picked, and colony PCR was performed to identify full-length clones. For all six assembled genes, six colonies were sequenced to determine the number of sequence-correct clones.
Gateway cloning example with GeneArt Strings DNA Fragments
Five Strings DNA Fragments up to 1,000 bp with attB sites were cloned into pDONR 221. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Eight colonies were picked, and colony PCR was performed to identify full-length clones; four to seven full-length clones were sequenced to determine the number of sequence-correct clones.
The percentage of clones with correct length as identified by colony PCR (cloning efficiency) and the percent of sequence-correct clones (fidelity) based on the number of full-length clones.
Recommendations for cloning and sequence design
Strings DNA products can be cloned using any available cloning method, provided the appropriate ends have been included in the design. End sequences can be added prior to uploading the sequence into the GeneArt Services Dashboard or they can be added after import.
| Cloning method | Recommended sequence design |
|---|---|
| Restriction enzyme cloning | Add desired 5′ and 3′ restriction enzyme sequences, plus stuffer nucleotides on each end to ensure efficient enzyme binding |
| GeneArt Type IIs Assembly | Add desired 5′ and 3′ restriction enzyme sequences, plus stuffer nucleotides on each end to ensure efficient enzyme binding |
| Invitrogen GeneArt Seamless Cloning and Assembly | Add 15 bp sequence overlap (or more, depending on the kit) to vector or adjacent insert |
| Invitrogen Gateway Cloning | Add attB sites to enable proper recombination into Invitrogen pDONR vector |
| Invitrogen Zero Blunt TOPO PCR Cloning | Strings Fragments are blunt ended, so 5–10 stuffer nucleotides are recommended to compensate for small terminal truncations |
| TA and Invitrogen TOPO TA Cloning | Strings Fragments are blunt-ended and need to be adenylated using a Taq polymerase in the presence of dATP to add end-terminal A-overhangs |
Recommendations for screening
Strings DNA Fragments are PCR amplicons of assembled oligonucleotides, ready for screening to identify the correct clone. Strings DNA Fragments are bulk sequenced as part of the quality control process to help ensure that your desired sequence is present in the fragment pool.
To identify a correct clone >90% of the time, we recommend using the following screening guidelines.
| Length of Strings Fragment | Screening recommendation |
|---|---|
| Up to 1 kb | Sequence 2 to 4 full-length clones |
| 1–2 kb | Sequence 3 to 5 full-length clones |
| 2–3 kb | Sequence 4 to 8 full-length clones |
GeneArt Strings DNA Fragments are custom-made, uncloned, double-stranded linear DNA fragments, available in lengths from 200 base pairs (bp) to 3,000, assembled from synthetic oligonucleotides using the same process developed for GeneArt high-quality gene synthesis. Strings Fragments can be used to quickly clone your gene of interest. At least 200 ng of Strings DNA Fragments are produced within 3-5 (up to 1,000 bp) or 8 (from 1,000 to 3,000 bp) business days. GeneArt Strings DNA Fragments can be designed, sequence optimized, and ordered online and are a cost-effective and smart alternative to clone your expression plasmid.
While we used to offer Strings DNA Fragments between 100 – 199 bp, this is unfortunately no longer possible.
Strings Fragments are amplicons (PCR amplificates) of assembled oligonucleotides; an intermediate product of the gene synthesis production process. This process results in a pool of fragments, and cloning and screening need to be carried out to identify the correct clone. To ensure that correct fragments are present in the pool, Strings Fragments are bulk sequence-controlled before shipment.
Strings DNA Fragments are shipped dried, ready for resuspension and cloning. Before using, we recommend that you spin down the tube contents, add some water to the bottom of the tube to get the desired concentration, and let it incubate for at least 1 hour at room temperature (alternatively incubate at 4°C overnight). Subsequently, resuspend carefully and use immediately. For longer storage, resuspended Strings DNA Fragments should be dispensed into aliquots and frozen at –20°C. Please avoid freeze-thaw cycles.
No. Strings DNA Fragments from 200 to 1,000 bp are produced in 5 business days and Strings DNA Fragments from 1,000 to 3,000 bp are produced in 8 business days. Depending on the nature of the sequence, production time can vary.
Yes. Since you need to perform the cloning to obtain your final gene, Strings DNA Fragments prices are always below those for gene synthesis.
Yes. We recommend using the GeneArt web order portal for ordering, where you can use the free gene editing and optimization functions to adjust the sequence to meet your needs. After editing and optimization, please check again that the final sequences of the fragment(s) are exactly as needed for further processing in your lab (e.g., potential homologous overlaps of the fragments or restriction sites and buffer bases needed for cloning).
No, subcloning and assembly services are not available for Strings DNA Fragments, as they are designed to offer you the fastest and most affordable way to get access to your genes. If you do not want to clone your gene yourself, we recommend that you order full gene synthesis service.
Yes, it is possible to directly assemble 2 Strings Fragments without pre-cloning. Thermo Fisher Scientific offers several technologies for seamless assembly, e.g., GeneArt Type IIs Assembly or GeneArt Seamless Cloning and Assembly. Please refer to the application examples section on this page for more information. Depending on the sequence length and the number of subfragments you want to assemble, the screening effort to find a correct clone can be high. We therefore generally recommend pre-cloning the subfragments to limit the screening effort required to find a correct clone after assembly.
No. Strings DNA Fragments are limited to 200 to 3,000 bp. If your sequence is longer, you need to order it as gene synthesis or assemble your gene from two or more Strings DNA Fragments. In addition, the Strings DNA Fragments manufacturing process is streamlined to very quickly and cost-effectively provide you with your gene product. If your sequence is complex, you may receive a message that it cannot be produced as a Strings DNA Fragment due to high complexity. In that case, we recommend modifying your sequence to match the production criteria (given below) or ordering your gene as gene synthesis. In many cases, optimizing your sequence using the portal function enables manufacturing with the Strings Fragments process. If it is still not able to be produced, you can manually edit the sequence to enable production.
Important production criteria are:
- GC content between 20% to 80% (in peaks, not overall content)
- No long secondary structures or sequence repetitions
- No A/T stretches >25 bp nor G/C stretches >20 bp
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Support
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Geneartsupport@thermofisher.com
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Europe: +49 (0)941 942 76-100
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