Bac-to-Bac™ C-His TOPO™ Expression System
Bac-to-Bac™ C-His TOPO™ Expression System
Gibco™

Bac-to-Bac™ C-His TOPO™ Expression System

Bac-to-Bac baculovirus expression is an efficient method for producing baculovirus for high-level protein expression in insect cells. It relies onLeia mais
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Número do catálogoQuantity
A1110020 Reactions
Número do catálogo A11100
Preço (BRL)
-
Quantity:
20 Reactions
Bac-to-Bac baculovirus expression is an efficient method for producing baculovirus for high-level protein expression in insect cells. It relies on generation of recombinant virus by site-specific transposition in E. coli rather than homologous recombination in insect cells. The pFastBac C-His TOPO expression system features:

Flexibility—The Bac-to-Bac C-His TOPO vector contains a C-terminal His-tag with a TEV cleavage site for easy purification of His- tagged proteins with nickel-chelating resins (such as the Invitrogen ProBond Purification System) and generation of native proteins with the aid of the Invitrogen AcTEV Protease.

Fast cloning, easy screening—Blunt TOPO cloning technology enables cloning of blunt-end PCR products into the pFastBac TOPO vector in five minutes. In addition, the pFastBac TOPO expression kit is supplied with Mach1-T1R E. coli that enable the visualization of colonies eight hours after plating on ampicillin-selective plates due to their faster doubling time compared to other standard cloning strains. Find out more about the advantages of TOPO cloning ›

High transfection efficiency with ExpiFectamine Sf Transfection Reagent—The Bac-to-Bac TOPO expression kits now come with the next-generation ExpiFectamine Sf Transfection Reagent for efficient DNA transfection in insect cells using fast, flexible protocols. Find out more about this reagent ›

Time-saving expression bacmid—With the Bac-to-Bac system, the expression cassette of the pFastBac vector recombines with the parent bacmid in DH10Bac E. coli Competent Cells to form an expression bacmid. The bacmid is then transfected into insect cells for production of recombinant baculovirus particles.

Easy colony screening—The parent bacmid in DH10Bac E. coli contains a segment of the lacZa gene. The lacZa gene is disrupted upon transposition of the expression cassette into the bacmid, allowing for blue/white selection of recombinants for easier identification of recombinant colonies.

High protein expression—The pFastBac vector uses the strong polyhedrin promoter to generate high levels of expression in a variety of insect cell line such as Sf9, Sf21, and High Five cells.

For Research Use Only. Not for use in diagnostic procedures.
Especificações
Antibiotic Resistance BacterialAmpicillin (AmpR), Gentamicin (GmR)
Cloning MethodBlunt TOPO™
Expression MechanismCell-Based Expression
FormatLiquid
Product LineBac-to-Bac, TOPO
Protein TagHis-Tag (6x)
Quantity20 Reactions
Expression SystemBaculovirus
PromoterPolyhedrin
TypeExpression System
Unit SizeEach
Conteúdo e armazenamento
Bac-to-Bac C-His TOPO Expression Kit:
• Vector kit for 20 TOPO cloning reactions, store at -20°C
   –pFastBac/CT-TOPO vector containing the C-terminal TEV cleavage sit and His-tag
   –pFastBac 1-Gus control plasmid (control expression vector)
   –Other kit reagents: 10X PCR, dNTP mix, Salt solution, sterile water, control PCR template, polyhedrin forward primer, SV40 pA reverse primer
• One Shot Mach1-T1R Chemically Competent E. coli for 20 reactions (20 x 50 μL), store at -80°C
• MAX Efficiency DH10Bac Competent E. coli for 20 reactions (4 kits with 5 x 0.1 mL each), store at -80°C
• ExpiFectamine Sf Transfection Reagent (1 mL), store at 4°C, do not freeze

Frequently asked questions (FAQs)

I cannot detect any recombinant fusion protein after using the BaculoDirect Expression Kit. What could be the cause for this and what do you suggest I try?

Please check the construction of your entry clone, and ensure that the insert is in frame with the vector. Analyze the recombinant viral DNA by PCR to confirm the correct size and orientation of your insert after the LR reaction. Sequence your PCR product to verify the proper reading frame for expression of the epitope tag.

Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.

I'm getting a low-titer P1 viral stock and would like to generate a high-titer stock. What should I do?

To get a high-titer stock, reinfect cells with the P1 stock and generate a P2 high-titer stock. Follow the directions in the BaculoDirect manual on page 18 to generate your P2 stock.

Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.

I performed an LR reaction, followed by transfection into Sf9/Sf21 insect cells, but do not see any signs of infection even though it's been 72 hours. What should i do?

Please see our recommendations below:

- Check the LR reaction by PCR analysis prior to transfection into insect cells.
- We recommend using Grace's Insect Cell Culture Medium, Unsupplemented during the transfection experiment instead of serum-free medium, as components in serum-free medium may interfere with transfection.
- Ensure that FBS, supplements, or antibiotics are not included during transfection, as the proteins in these materials can interfere with the Cellfectin II Reagent.
- Use the LR recombination reaction using the pENTR/CAT plasmid as a positive control and Cellfectin II Reagent only (mock transfection) as a negative control.
- Ensure that cells are in the log phase of growth with >95% viability, and the amount of cells are in accordance with the suggestions in the manual.
- Cells may not show signs of viral infection for up to a week depending on transfection efficiency; continue culturing and monitor cells daily for signs of infection.

I see a precipitate in my ganciclovir solution. What can I do?

Warm the ganciclovir solution in a water bath at 37 degrees C for 5-10 min, then vortex for a few minutes. The precipitate should go back into solution.

Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.

I am purifying my secreted protein expressed in insect cells with a His-tagged purification column and getting no yield of my protein. Why and what can I do?

Media used to culture insect cells usually have an acidic pH (6.0-6.5) or contain electron-donating groups that can prevent binding of the 6xHis-tagged protein to Ni-NTA. Amino acids such as glutamine, glycine, or histidine are present at significantly higher concentrations in media for growing insect cells than in media for growing mammalian cells, and compete with the 6xHis-tagged protein for binding sites on Ni-NTA matrices. Grace's medium (Thermo Fisher Scientific), for example, contains approximately 10 mM glutamine, 10 mM glycine, and 15 mM histidine.

Dialysis of the medium against a buffer with the appropriate composition and pH (8.0) similar to the lysis buffer recommended for purification under native conditions usually restores optimal binding conditions. Note that depending on the medium used, a white precipitate (probably made up of insoluble salts) can occur, but normally the 6xHis-tagged protein remains in solution. This can be tested by either protein quantitation if using a protein-free medium or by monitoring the amount of 6xHis-tagged protein by western-blot analysis. After centrifugation, 6xHis-tagged protein can be directly purified from the cleared supernatant.

Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.