About 50 Papers Cited the Use of GFP-Trap Camelid Antibody So Far in 2011

With their ability to quantitatively pulldown GFP-tagged proteins, GFP-Trap (or RFP-Trap for DsRed-derived fluorescent proteins) beads have gained ground in becoming the reagent of choice for immuno-coprecipitation. The complexes isolated from GFP-Trap agarose or magnetic beads can be easily analyzed without interference from light or heavy IgG chains typically present after monoclonal or polyclonal antibody precipitation. Since the market launch of GFP-Trap, in each of the past 3 years, the number of publications citing GFP-Trap more has than doubled and there is no sign of that rate slowing down any time soon.

In 2011 alone, 48 research groups have published their results with data generated through use of GFP-Trap (not including other related products such as GFP-Booster, GFP-MultiTrap). Research topics in these recent publications include identification of domains of the zinc finger protein 638 (ZNF638) that interacts with C/EBP? when promoting adipocyte differentiation [1]; identification of phosphorylation site on Cdc42-associated kinase (Ack) by LC-MS/MS after immunoprecipitation [2]; and analysis of the activities of myosin heavy-chain kinases (MHCKs) in wild-type vs Htt mutant Dictyostelium discoideum, a cellular model for studying the Huntingon disease [3].

The use of GFP-Trap beads is a simple bind-wash-elute procedure that involves just one antibody already immobilized on either agarose or magnetic beads. Camelid antibodies, especially their VHH single domain fragments such as those used in GFP-Trap or RFP-Trap, are very stable (they can be shipped and temporarily stored at room temperature). The consistency of performance is very high; as a matter of fact, this line of products requires the lowest amount of technical support among all of our products. If you are still using tags like FLAG, V5, HA, etc., you should consider trying GFP as both a fluorescence and co-IP tag in your future experiments for obtaining results you previously could not obtain.

New Product of the Week: Non-Integrating iPSC Generation Kits. First of its kind on the market. Click to read more about mRNA-based reprogramming.

Promotion of the Week: Save 15% to save the environment by using EcoCulture Dishes at 30% less plastic for better imaging. Code: 091911DISH when call or email us.

Blog References:
[1] Meruvu, S. et al. “Regulation of Adipocyte Differentiation by the Zinc Finger Protein ZNF638″ JBC 2011
[2] Shen, H. et al. “Constitutive activated Cdc42-associated kinase (Ack) phosphorylation at arrested endocytic clathrin-coated pits of cells that lack dynamin” Molecular Biology of the Cell 2011
[3] Wang, Y. et al. “Dictyostelium huntingtin controls chemotaxis and cytokinesis through the regulation of myosin II phosphorylation” Molecular Biology of the Cell 2011

Expanding the Camelid Antibody Product Line

From AlleleBlog http://allelebiotech.com/blogs/

While Chromotek GFP-Trap resin has become one of the best sellers from the Allele Biotech’ Camelid 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.

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

http://allelebiotech.com/blogs/2010/03/using-2a-%E2%80%9Cself-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.

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!