PfxUltima with TOPO TA Cloning® Kit with One Shot® TOP10 Chemically Competent E. coli - FAQs

pCR2.1-TOPO和pCR4-TOPO载体有什么区别？

两个载体的骨架非常相似。主要的不同在于pCR4-TOPO载体测序引物位点距离PCR产物插入位点仅33 bp。这使得对插入序列进行测序时需要读取的载体序列能最小化，从而使pCR4-TOPO载体非常适合进行测序应用。

pCR2.1-TOPO 和pCRII-TOPO载体的区别是什么？

两个载体的骨架非常相似。主要的不同在于pCRII-TOPO 载体是一个双启动子载体，包含SP6和T7启动子用于体外转录/测序，而 pCR2.1-TOPO仅包含T7启动子用于体外转录/测序。两个载体均含有M13 正向和反向引物位点用于测序或PCR检测。

你们的TOPO克隆试剂盒包含一个对照模板和一个对照引物。我可以获得对照模板的序列吗？

对照模板的序列是受专利保护的。

我可以使用包含Taq聚合酶和一个校对活性聚合酶的DNA聚合酶混合物进行TOPO TA克隆吗？

如果你想使用包含Taq聚合酶和一个校对活性聚合酶的DNA聚合酶混合物，Taq酶和校对活性聚合酶的比例必须超过10:1以确保PCR产物带有3´ A突起。如果你使用的聚合酶混合物没有足够的Taq聚合酶或仅含有校对活性聚合酶，你可以在PCR反应后添加3´ A突起。请参阅产品手册获取细节。 适合TOPO TA克隆的一些Taq酶混合物的例子包括Platinum Taq DNA Polymerase High Fidelity和AccuPrime Taq DNA Polymerase High Fidelity。

What is the difference between the pCR2.1-TOPO and pCR4-TOPO vectors?

The vector backbones for both of these vectors are very similar. The main difference is that the pCR4-TOPO vector has sequencing primer sites located as close as 33 base pairs from the PCR product insertion site. This minimizes the amount of vector DNA sequence that needs to be read before reaching the sequence of the insert, making the pCR4-TOPO vector very useful for sequencing applications.

What is the difference between the pCR2.1-TOPO and pCRII-TOPO vectors?

The vector backbones for both of these vectors are very similar. The main difference is that the pCRII-TOPO vector is a dual promoter vector, containing the SP6 and T7 promoters for in vitro transcription/sequencing, whereas the pCR2.1-TOPO vector contains only the T7 promoter for in vitro transcription/sequencing. Both vectors contain the M13 Forward and Reverse primer sites for sequencing or PCR screening.

Your TOPO cloning kits contain a control template and control primers. Can I obtain the sequence of the control template?

The sequence of the control template is proprietary.

What PCR enzyme would you recommend for use with the Directional TOPO Cloning Kits?

For the Directional TOPO Cloning Vectors, a PCR product must be generated by a proofreading enzyme to create a blunt product. Pfx50 or Accuprime Pfx and Accuprime Pfx Supermix from Thermo Fisher Scientific are recommended for use.

When cloning a Pfx-amplified PCR product, the insert to vector ratio is an important consideration. The PCR product generally needs to be diluted since Pfx generates a high concentration of product and using too much insert DNA can hamper the TOPO reaction. A 1:1 molar ratio of vector to insert (or about 2-10ng of insert) is recommended.

Can I use a DNA polymerase mixture containing both Taq polymerase and a proofreading polymerase for TA Cloning?

If you wish to use a polymerase mixture containing Taq polymerase and a proofreading polymerase, Taq must be used in excess with a 10:1 ratio of Taq to the proofreading enzyme to ensure the presence of 3´ A-overhangs on the PCR product. If you use polymerase mixtures that do not have enough Taq polymerase or a proofreading polymerase only, you can add 3' A-overhangs following PCR. See the vector product manuals for details.

Some examples of Taq blends that are compatible with TOPO TA Cloning are Platinum Taq DNA Polymerase High Fidelity and AccuPrime Taq DNA Polymerase High Fidelity.

How does TA Cloning work?

Taq polymerase has a non-template-dependent terminal transferase activity that adds a single deoxyadenosine (A) to the 3´ ends of PCR products. The linearized vector supplied in our TA Cloning kits have single, overhanging 3´ deoxythymidine (T) residues. This allows PCR inserts to ligate efficiently with the vector.

What are the melting temperatures for the M13 Forward (-20) and M13 Reverse primers in the TOPO Cloning and Zero Blunt Kits?

Assuming that the primer is at a 50 nM final concentration and 50 mM final salt concentration, the melting temperatures are: M13 Forward (-20) Primer = 52.7 and the M13 Reverse Primer = 45.3. For use in the control PCR reaction we recommend using an annealing temperature of 56C.