Invitrogen™ pLenti7.3/V5-DEST™ Gateway™ Vector Kit

Catalog No.	Quantity
V53406	1 Kit

Catalog No. V53406 Supplier Invitrogen™ Supplier No. V53406

Description

The pLenti7.3/V5-DEST™ Gateway™ Vector Kit contains the Gateway™-adapted ViraPower™ HiPerform™ lentiviral expression vector, pLenti7.3/V5-DEST™ for easy recombination-based cloning and high-level expression of a target gene in dividing and non-dividing mammalian cells.

The pLenti7.3/V5-DEST™ Gateway™ Vector Kit contains the Gateway™-adapted ViraPower™ HiPerform™ lentiviral expression vector, pLenti7.3/V5-DEST™ for easy recombination-based cloning and high-level expression of a target gene in dividing and non-dividing mammalian cells. The pLenti7.3/V5-DEST™ vector is equipped with two key genetic elements, making it a HiPerform™ vector: the Woodchuck Posttranscriptional Regulatory Element (WPRE) and the central Polypurine Tract (cPPT) sequence from the HIV-1 integrase gene to produce at least 4-fold increase in protein expression compared to vectors lacking these elements. In addition, the vector allows for an accurate determination of titer of functional lentivirus in just two days using Emerald Green Fluorescent Protein (EmGFP).

Advantages

• Transient expression
• Short-term experiments
• High-throughput screening
• 2 day titer of functional virus using EmGFP
• Flexible and versatile Gateway™ recombination cloning technology

Key Features

• WPRE (Woodchuck Posttranscriptional Regulatory Element) from the woodchuck hepatitis virus, allows increased transgene expression and cPPT (Polypurine Tract) from the HIV-1 integrase gene, increases the copy number of lentivirus integrating into the host genome
• Human cytomegalovirus (CMV) immediate early promoter to control high-level expression of the gene of interest
• SV40 promoter driving expression of EmGFP
• Emerald Green Fluorescent Protein (EmGFP) allows easy determination of Lentiviral titers by flow cytometry and monitor transduced cells.

Kit Includes

• pLenti7.3/V5-DEST™ Gateway™ Vector box
• One Shot™ Stbl3™ chemically competent E. coli (Cat. No. C7373-03)

Related SKUs

• 293FT Cell Line (Cat. No. R70007)
• ViraPower™ Lentiviral Support Kit (K4970-00)
• ViraPower™ Lentiviral Packaging Mix (K4975-00)
• Lipofectamine™ 2000 (11668-019, 11668-027)

Specifications

• Constitutive or Inducible System: Constitutive
• Delivery Type: Lentiviral
• Promoter: CMV
• Product Type: Lentiviral Expression Vector
• Reporter Gene: GFP (EmGFP)
• Selection Agent (Eukaryotic): None
• Content And Storage: pLenti7.3/V5-DEST™ Gateway™ Vector Kit
  • pLenti7.3/V5-DEST™ Gateway™ Vector (150 ng/μL), 40 μL
  • pLenti7.3/V5-GW/lacZ Control Vector (0.5 μg/μL), 20 μL
  Store at -20°C.
  
  One Shot™ Stbl3™ Chemically Competent E. coli box
  Transformation reagents including:
  • One Shot™ Competent Cells, 20 x 50 μL single-use aliquots
  • S.O.C. medium
  • pUC19 supercoiled plasmid control
  Store at -80°C.
• Protein Tag: V5 Epitope Tag
• Cloning Method: Gateway
• Quantity: 1 Kit
• Vector: pLenti
• Product Line: ViraPower, Gateway, HIPERFORM
• For Use With (Application): Reporter Assays, Viral Expression

Frequently Asked Questions (FAQs)

Can I perform the single-step protocol for the BP/LR Clonase reaction using BP Clonase enzyme and LR Clonase enzyme instead of BP Clonase II enzyme and LR Clonase II enzyme?

In the single-step protocol for the BP/LR Clonase reaction, we would not recommend substituting the BP Clonase II/LR Clonase II enzymes with BP Clonase /LR Clonase enzymes as this would result in very low recombination efficiency.

Do you have a recommended single-step protocol for BP/LR recombination?

Yes, we have come up with a single-step protocol for BP/LR Clonase reaction (http://www.thermofisher.com/us/en/home/life-science/cloning/gateway-cloning.html#1), where DNA fragments can be cloned into Destination vectors in a single step reaction, allowing you to save time and money.

How can I move my gene of interest from a Gateway-adapted expression clone to a new Destination vector as I have lost the entry clone?

We would recommend performing a BP reaction with a Donor vector in order to obtain an entry clone. This entry clone can then be used in an LR reaction with the Destination vector to obtain the new expression clone.

Can I purchase the 5X LR Clonase buffer or 5X BP Clonase buffer separately?

We do not offer the 5X LR Clonase buffer and 5X BP Clonase buffer as standalone products. They are available as part of the enzyme kits.

Do you offer Gateway vectors for expression in plants?

We do not offer any Gateway vectors for expression in plants.

I used fluorescence microscopy to check the lentiviral titer with one of your ViraPower HiPerform FastTiter lentiviral vectors but the titer was very low. Did I do something wrong?

With the HiPerform FastTiter lentiviral vectors, the fluorescence signal intensity of EmGFP in the cells is not optimal for visual evaluation using fluorescence microscopy. With these vectors, we recommend using only flow cytometry to detect the EmGFP in transduced cells.

What is special about the ViraPower HiPerform Lentiviral FastTiter Expression System?

In the ViraPower HiPerform Lentiviral FastTiter Expression System, the lentiviral expression vector contains the WPRE and cPPT elements. In addition, it contains the EmGFP reporter gene in the vector backbone instead of Bsd, which allows titer of functional virus by flow cytometry in just two days post-transduction. Note: The FastTiter Expression Kits are optimal for quick screens of transient expression using flow cytometry. While the quantity of cells expressing the gene of interest is significantly greater than with other pLenti vectors that do not contain the WPRE and cPPT elements, the fluorescence signal intensity of EmGFP produced by these kits is not optimal for detection using fluorescence microscopy. Hence, we recommend flow cytometry to detect the EmGFP in transduced cells.

I performed stable selection but my antibiotic-resistant clones do not express my gene of interest. What could have gone wrong?

Here are possible causes and solutions:

Detection method may not be appropriate or sensitive enough:
- We recommend optimizing the detection protocol or finding more sensitive methods. If the protein is being detected by Coomassie/silver staining, we recommend doing a western blot for increased sensitivity. The presence of endogenous proteins in the lysate may obscure the protein of interest in a Coomassie/silver stain. If available, we recommend using a positive control for the western blot.
- Insufficient number of clones screened: Screen at least 20 clones.
- Inappropriate antibiotic concentration used for stable selection: Make sure the antibiotic kill curve was performed correctly. Since the potency of a given antibiotic depends upon cell type, serum, medium, and culture technique, the dose must be determined each time a stable selection is performed. Even the stable cell lines we offer may be more or less sensitive to the dose we recommend if the medium or serum is significantly different.
- Expression of gene product (even low level) may not be compatible with growth of the cell line: Use an inducible expression system.
- Negative clones may result from preferential linearization at a vector site critical for expression of the gene of interest: Linearize the vector at a site that is not critical for expression, such as within the bacterial resistance marker.

I used a mammalian expression vector but do not get any expression of my protein. Can you help me troubleshoot?

Here are possible causes and solutions:

- Try the control expression that is included in the kit
Possible detection problem:

- Detection of expressed protein may not be possible in a transient transfection, since the transfection efficiency may be too low for detection by methods that assess the entire transfected population. We recommend optimizing the transfection efficiency, doing stable selection, or using methods that permit examination of individual cells. You can also increase the level of expression by changing the promoter or cell type.
- Expression within the cell may be too low for the chosen detection method. We recommend optimizing the detection protocol or finding more sensitive methods. If the protein is being detected by Coomassie/silver staining, we recommend doing a western blot for increased sensitivity. The presence of endogenous proteins in the lysate may obscure the protein of interest in a Coomassie/silver stain. If available, we recommend using a positive control for the western blot. Protein might be degraded or truncated: Check on a Northern. Possible time-course issue: Since the expression of a protein over time will depend upon the nature of the protein, we always recommend doing a time course for expression. A pilot time-course assay will help to determine the optimal window for expression. Possible cloning issues: Verify clones by restriction digestion and/or sequencing.

I am using a mammalian expression vector that has the neomycin resistance gene. Can I use neomycin for stable selection in mammalian cells?

No; neomycin is toxic to mammalian cells. We recommend using Geneticin (a.k.a. G418 Sulfate), as it is a less toxic and very effective alternative for selection in mammalian cells.

Is it okay if my construct has an ATG that is upstream of the ATG in my gene of interest? Will it interfere with translation of my gene?

Translation initiation will occur at the first ATG encountered by the ribosome, although in the absence of a Kozak sequence, initiation will be relatively weak. Any insert downstream would express a fusion protein if it is in frame with this initial ATG, but levels of expressed protein are predicted to be low if there is a non-Kozak consensus sequence. If the vector contains a non-Kozak consensus ATG, we recommend that you clone your gene upstream of that ATG and include a Kozak sequence for optimal expression.

Do you offer a GFP-expressing mammalian expression vector that I can use as a control to monitor my transfection and expression?

We offer pJTI R4 Exp CMV EmGFP pA Vector, Cat. No. A14146, which you can use to monitor your transfection and expression.

Which competent E. coli do you recommend using for propagation of my Gateway-adapted mammalian Destination vector?

We recommend using One Shot ccdB Survival 2 T1R Competent Cells, Cat. No. A10460. This strain is resistant to the toxic effects of the ccdB gene. Note: Do not use general E. coli cloning strains, including TOP10 or DH5alpha, for propagation and maintenance, as these strains are sensitive to ccdB effects.

I am working with a mouse cell line and would like to express my gene at high levels using one of your vectors with the CMV promoter. Do you foresee any problems with this approach?

The CMV promoter is known to be downregulated over time in mouse cell lines. Hence, we recommend using one of our non-CMV vectors, such as those with the EF1alpha or UbC promoter, for long-term expression in mouse cell lines.

Do I need to include a consensus Kozak sequence when I clone my gene of interest into one of your mammalian expression vectors?

The consensus Kozak sequence is A/G NNATGG, where the ATG indicates the initiation codon. Point mutations in the nucleotides surrounding the ATG have been shown to modulate translation efficiency. Although we make a general recommendation to include a Kozak consensus sequence, the necessity depends on the gene of interest and often, the ATG alone may be sufficient for efficient translation initiation. The best advice is to keep the native start site found in the cDNA unless one knows that it is not functionally ideal. If concerned about expression, it is advisable to test two constructs, one with the native start site and the other with a consensus Kozak. In general, all expression vectors that have an N-terminal fusion will already have an initiation site for translation.

Do I need to include a ribosomal binding site (RBS/Shine Dalgarno sequence) or Kozak sequence when I clone my gene of interest?

ATG is often sufficient for efficient translation initiation although it depends upon the gene of interest. The best advice is to keep the native start site found in the cDNA unless one knows that it is not functionally ideal. If concerned about expression, it is advisable to test two constructs, one with the native start site and the other with a Shine Dalgarno sequence/RBS or consensus Kozak sequence (ACCAUGG), as the case may be. In general, all expression vectors that have an N-terminal fusion will already have a RBS or initiation site for translation.

Can you tell me the difference between a Shine-Dalgarno sequence and a Kozak sequence?

Prokaryotic mRNAs contain a Shine-Dalgarno sequence, also known as a ribosome binding site (RBS), which is composed of the polypurine sequence AGGAGG located just 5’ of the AUG initiation codon. This sequence allows the message to bind efficiently to the ribosome due to its complementarity with the 3’-end of the 16S rRNA. Similarly, eukaryotic (and specifically mammalian) mRNA also contains sequence information important for efficient translation. However, this sequence, termed a Kozak sequence, is not a true ribosome binding site, but rather a translation initiation enhancer. The Kozak consensus sequence is ACCAUGG, where AUG is the initiation codon. A purine (A/G) in position -3 has a dominant effect; with a pyrimidine (C/T) in position -3, translation becomes more sensitive to changes in positions -1, -2, and +4. Expression levels can be reduced up to 95% when the -3 position is changed from a purine to pyrimidine. The +4 position has less influence on expression levels where approximately 50% reduction is seen. See the following references:

- Kozak, M. (1986) Point mutations define a sequence flanking the AUG initiator codon that modulates translation by eukaryotic ribosomes. Cell 44, 283-292.
- Kozak, M. (1987) At least six nucleotides preceding the AUG initiator codon enhance translation in mammalian cells. J. Mol. Biol. 196, 947-950.
- Kozak, M. (1987) An analysis of 5´-noncoding sequences from 699 vertebrate messenger RNAs. Nucleic Acids Res. 15, 8125-8148.
- Kozak, M. (1989) The scanning model for translation: An update. J. Cell Biol. 108, 229-241.
- Kozak, M. (1990) Evaluation of the fidelity of initiation of translation in reticulocyte lysates from commercial sources. Nucleic Acids Res. 18, 2828.

Note: The optimal Kozak sequence for Drosophila differs slightly, and yeast do not follow this rule at all. See the following references:

- Romanos, M.A., Scorer, C.A., Clare, J.J. (1992) Foreign gene expression in yeast: a review. Yeast 8, 423-488.
- Cavaneer, D.R. (1987) Comparison of the consensus sequence flanking translational start sites in Drosophila and vertebrates. Nucleic Acids Res. 15, 1353-1361.

What is the consensus Kozak sequence and what is the function of the Kozak sequence?

Eukaryotic (and specifically mammalian) mRNA contains sequence information that is important for efficient translation. However, this sequence, termed a Kozak sequence, is not a true ribosome binding site, but rather a translation initiation enhancer. The Kozak consensus sequence is ACCAUGG, where AUG is the initiation codon. A purine (A/G) in position -3 has a dominant effect; with a pyrimidine (C/T) in position -3, translation becomes more sensitive to changes in positions -1, -2, and +4. Expression levels can be reduced up to 95% when the -3 position is changed from a purine to pyrimidine. The +4 position has less influence on expression levels where approximately 50% reduction is seen. See the following references:

Kozak, M. (1986) Point mutations define a sequence flanking the AUG initiator codon that modulates translation by eukaryotic ribosomes. Cell 44, 283-292.
Kozak, M. (1987) At least six nucleotides preceding the AUG initiator codon enhance translation in mammalian cells. J. Mol. Biol. 196, 947-950.
Kozak, M. (1987) An analysis of 5´-noncoding sequences from 699 vertebrate messenger RNAs. Nucleic Acids Res. 15, 8125-8148.
Kozak, M. (1989) The scanning model for translation: An update. J. Cell Biol. 108, 229-241.
Kozak, M. (1990) Evaluation of the fidelity of initiation of translation in reticulocyte lysates from commercial sources. Nucleic Acids Res. 18, 2828.

Note: The optimal Kozak sequence for Drosophila differs slightly, and yeast do not follow this rule at all. See the following references:

Romanos, M.A., Scorer, C.A., Clare, J.J. (1992) Foreign gene expression in yeast: a review. Yeast 8, 423-488.
Cavaneer, D.R. (1987) Comparison of the consensus sequence flanking translational start sites in Drosophila and vertebrates. Nucleic Acids Res. 15, 1353-1361.

For Research Use Only. Not for use in diagnostic procedures.