Expanding the Camelid Antibody Product Line

While Chromotek GFP-Trap resin has become one of the best sellers from the Allele Biotech’ Camelid Antibody (VHH antibody) product line, more products have been added that will prove to be great tools for GFP-related research.

GFP is a powerful tool to study protein localization and dynamics in living cells. However, the photo stability and the quantum efficiency of GFP are not sufficient for Super-Resolution Microscopy (e.g. 3D-SIM or STED) of fixed samples from cells expressing GFP-fusion proteins to visualize specific structures. Furthermore, many cell biological methods such as HCl treatment for BrdU-detection, the EdU-Click-iT™ treatment or heat denaturation for FISH lead to disruption of GFP signal.

Now we offer our GFP-Trap Booster for reactivation, boosting and stabilization of GFP, suitable for acquiring strong and long lasting signals from GFP-fusion proteins. It is based on a specific GFP-binding protein as in GFP-Trap but coupled to the fluorescent dye ATTO 488 (from ATTO-TEC). For information, please read the product description of this week New Product of the Week: GFP-Trap booster, ABP-CM-GBOOSTR, http://www.allelebiotech.com/shopcart/index.php?c=221&sc=158

Promotion of the week: All mTFP1 and mWasabi fusion plasmids are 30% off for this week only

Preview of future new product: a similarly high quality product, the RFP-Trap that pulls down DsRed derived proteins including mRFP1, mCherry, mOrange, mPlum but also mRuby and RFP-tagged fusion proteins.

Tags: anti-GFP, Chromotek, GFP coIP, GFP-Trap, mCherry, mOrange, mPlum, mRFP1, mRuby RFP-tagged fusion proteins, nti-RFP, pulldown, RFP-Trap, VHH antibody

Anti-GFP antibody choices

A variety of anti-GFP antibodies are now provided to fluorescent protein users. In addition to the monoclonal anti-GFP antibody that has been introduced together with the GFP-Trap product group, Allele Biotech also has a strong anti-GFP polyclonal product, and a new rat anti-GFP monoclonal antibody. The availability of these different species specificity should allow users to have options in staining, detection, co-IP, double-labeling, etc.

New Product of the Week 04-05-10 to 04-11-10: Rat anti-AvGFP antibody, ACT-CM-MRGFP10

Promotion of the Week 04-05-10 to 04-11-10: Buy any Allele Biotech/Orbigen’s polyclonal antibody, get another of equal or less value at 60% off (if you are not a fan or friend through Allele’s online social networks, the discount is 30%).

Tags: 3H9, anti-GFP, antibodies, camelid antibodies, Chromotek, GFP booster, GFP detection, monoclonal, polyclonal, rat monoclonal

Using 2A “self-cleaving” peptide in bicistronic mammalian expression

Multiple promoters or internal ribosomal entry sites (IRES) have been used for the production of multiple proteins from the same vector. Potential drawbacks with multiple promoters on viral vectors include unstable genome and interference between promoters. IRES is a relatively large sequence that can cause problems in virus packaging, especially for viruses with very limited genome size such as AAV. In addition, it is required that the start of the second ORF is fairly close to the IRES, adding difficulties to cloning.

2A or 2A-like peptide (collectively called 2A peptide here) is used by several families of viruses, the best known foot-and-mouth disease virus of the Picornaviridae family, for producing multiple polypeptides. Although called a “self-cleaving” peptide or protease site, the mechanism by the 2A sequence for generating two proteins from one transcript is by ribosome skipping–a normal peptide bond is impaired at 2A, resulting in two discontinuous protein fragments from one translation even.

The 2A-based bicistronic expression has been used for several years, but recently gained much more popularity due to its successful use in iPSC generation that required 2 to 4 factors working in concert. Even expression of all factors can be achieved when 2A peptides are used for multiple protein production, due to near 100% efficiency of the 2A “cleavage” at each site, and no interference between multiple 2A sites. Early work used a 36 amino acid sequence as 2A peptide, which was later reduced to about half that size from mutation and screening. Commercial vectors utilizing 2A for co-expression of cDNA and fluorescent protein and/or drug resistance genes have not been available until now. Allele Biotech has introduced a number of such plasmids, establishing another First-to-the-market as it has done many times previously in its 10 year history.

New product of the week 03-29-10 to 04-04-10:

Alleleustrious pmTFP1-2A Bicistronic mammalian expression vector, ABP-FP-T2A10, $399, http://www.allelebiotech.com/shopcart/index.php?c=215&sc=34

Promotion of the week 03-29-10 to 04-04-10:

Buy any GFP-Trap beads or kits, get polyclonal anti-GFP (ABP-PAB-PAGFP10) at half size for FREE!  ***GFP-Trap has been replaced with GFP-nAb, an improved version for the same purposes in the form of agarose beads, magnetic beads, polyacrylamide beads, spin column kits, etc.  Come and take a look at the most comprehensive list of nearly all FPs before purchasing.

Tags: 2A peptide, anti-GFP, bicistronic, drug resistance, GFP-Trap, iPS, iPSCs, IRES, polycistronic, ribosome skip, self-cleaving, transcription, translation