Do You Know How Well Your Sunscreen Works?

Skin diseases caused by sun exposure include melanoma, basal cell carcinoma, squamous cell carcinoma, photoaging, as well as sunburn and many other conditions. According to the Skin Cancer Foundation, skin cancer is the most common type of cancer in the US. The vast majority of mutations found in melanoma, according to a 2009 study published in Nature [1], are caused by UV radiation.

Currently, commercial sunscreens are composed of physical sunblocks including zinc oxide and titanium dioxide, and chemical UV (ultraviolet lights) absorbers/filters such as octinoxate for UVB and benzophenone for UVA. The compositions of commercial sunscreen products are disclosed by the manufacturer and regulated by the health product regulatory authorities such the FDA in the US. The UV absorbers/filters are organic chemicals that absorb UV lights within a very limited range of wavelength. Consequently, a combination of different chemicals is needed to achieve “broad-spectrum” protection.

Currently the FDA required test of effectiveness of UV protection measures only UVB, which means there is no way of knowing how effective a sunscreen product is against cancer-causing UVA and damaging visible lights [2]. Even though the life style changes in recent time result in more damaging light exposure such as extended sun bathing on beach or tanning in beauty saloons, etc., only 3 new sunscreen active components (and none of new chemical class) have been introduced to the US market in more than 3 decades. There seems to be a gap between the need and the effort for developing substantially improved skin protection products.

1. Pleasance, E.D., R.K. Cheetham, P.J. Stephens, D.J. McBride, S.J. Humphray, C.D. Greenman, I. Varela, M.L. Lin, G.R. Ordonez, G.R. Bignell, K. Ye, J. Alipaz, M.J. Bauer, D. Beare, A. Butler, R.J. Carter, L. Chen, A.J. Cox, S. Edkins, P.I. Kokko-Gonzales, N.A. Gormley, R.J. Grocock, C.D. Haudenschild, M.M. Hims, T. James, M. Jia, Z. Kingsbury, C. Leroy, J. Marshall, A. Menzies, L.J. Mudie, Z. Ning, T. Royce, O.B. Schulz-Trieglaff, A. Spiridou, L.A. Stebbings, L. Szajkowski, J. Teague, D. Williamson, L. Chin, M.T. Ross, P.J. Campbell, D.R. Bentley, P.A. Futreal, and M.R. Stratton, A comprehensive catalogue of somatic mutations from a human cancer genome. Nature. 463(7278): p. 191-6.
2. Botta, C., C. Di Giorgio, A.S. Sabatier, and M. De Meo, Genotoxicity of visible light (400-800 nm) and photoprotection assessment of ectoin, L-ergothioneine and mannitol and four sunscreens. J Photochem Photobiol B, 2008. 91(1): p. 24-34.

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Tags: fluorescence, light exposure, melanoma, skin cancer, skin care, spectra, spectrum, sunburn, sunscreen, UVA, UVB, visible light

Delivery of RNAi or Cre by Ultrasound-Guided Injection of High Titer Lentiviral Vectors

By Jiwu Wang

According to the Skin Cancer Foundation, skin cancer is the most common type of cancer in the US. Although the skin might seem to be an easy target for gene therapy or RNAi mediated functional corrections, the outer keratinized epithelial cells forms a formidable barrier to delivery of genetic material. The epidermis undergoes rapid turnover, a fact that further complicates gene therapy because gene transfer to skin stem cells would be required for sustained effects.

Before skin gene therapy can be discussed with any practical meaning, a physiologically relevant in vivo model for studying gene function in the context of tumorigenesis and epithelial biology must be established. Studies of gene functions in skin homeostasis in mouse models were mostly performed by labor-intensive knockout methods. Recently, at least two publications have shown that by using ultrasound-guided injection of lentiviruses into amniotic fluids, transgene or shRNA can be efficiently and specifically delivered to epidermis, including skin stem cells, creating a very attractive model for functional studies and therapeutic tests.

Localized injection of high titer lentiviral vectors has been widely used for studying genes in brain development and a few other areas. Instead of injection into animal tissues, Endo et al. injected tiny volume (nl) of high titer lentivirus (10e10 TU/ml) into amniotic cavities within a defined window of embryogenesis [1]. By following fluorescent protein markers (CFP, GFP, YFP, RFP), both Endo et al. and researchers from Elaine Fuchs group demonstrated high efficiency and specificity of delivery to epithelial cells, commonly resulting in multiple genomic insertions of the viral genome.

RNAi against alfa1-catenin was used by Beronja and colleagues as an example to show that loss-of-function analysis can be done rather easily using shRNA/FP bearing lentivirus [2]. nlCre was also delivered to embryos with loxP-flanked transgenes vs wildtype for conditional knockout studies. These new findings should open doors to various experiments and therapies concerning the health of the skin.

1. Endo, M., P.W. Zoltick, W.H. Peranteau, A. Radu, N. Muvarak, M. Ito, Z. Yang, G. Cotsarelis, and A.W. Flake, Efficient in vivo targeting of epidermal stem cells by early gestational intraamniotic injection of lentiviral vector driven by the keratin 5 promoter. Mol Ther, 2008. 16(1): p. 131-7.
2. Beronja, S., G. Livshits, S. Williams, and E. Fuchs, Rapid functional dissection of genetic networks via tissue-specific transduction and RNAi in mouse embryos. Nat Med. 16(7): p. 821-7.

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Promotion of the Week

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Tags: cre, Fluorescent proteins, in vivo injection, lentiviral vector, lentivirus, loxP, nlCre, RNAi, shRNA, skin cancer, skin care, skin therapy, sunscreen, transgene

Allele’s pallet of the super star fluorescent proteins

“Photoblog”–just some fun pictures from our notebooks.

The brightest cyan, green fluorescent proteins, and the brightest ever FP in LanYFP!

These fluorescent proteins are representatives of the growing family or high quality, new generation FPs engineered to enable experiment previously deemed impossible.

Cells infected with lentivirus carrying mWasabi. Lentivirus carrying LanYFP will make most cells much more brighter than this.

The brightest green fluorescent protein with excellent photostability, carried on 10e8 TU/ml high titer lentivirus.

The LanFPs express well in bacteria.

Project planning is under way to test the cytotoxicity of lanFPs in different mammalian cell lines and in vivo with a focus on neurons.

The FPs fold so strongly that they fluorescence even in SDS-PAGE.

FPs in SDS PAGE–a closer look

FPs in gel cassette over UV lights

FPs in gel cassette under blue LED

The purified FPs can be used as “real time” protein markers.

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Tags: Fluorescent proteins, FP, FPs, FRET, GFP, lab note, lentivirus, mCherry, mTFP1, mWasabi, photos, pictures

17 Papers Using GFP-Trap, 12 Since 2009

1. MacKay C, Déclais AC, Lundin C et al. (2010). Identification of KIAA1018/FAN1, a DNA repair nuclease recruited to DNA damage by monoubiquitinated FANCD2. Cell 142:65-76.

2. Babiano R, de la Cruz J. (2010). Ribosomal protein L35 is required for 27SB pre-rRNA processing in Saccharomyces cerevisiae. Nucleic Acids Res 2010 Apr 14.

3. Fulcher AJ, Dias MM, Jans DA. (2010). Binding of p110 retinoblastoma protein inhibits nuclear import of simian virus SV40 large tumor antigen. J Biol Chem. 285:17744-53.

4. Taniue K, Nishida A, Hamada F et al. (2010). Sunspot, a link between Wingless signaling and endoreplication in Drosophila. Development. 137:1755-64.

5. Rottach A, Frauer C, Pichler G et al. (2010). The multi-domain protein Np95 connects DNA methylation and histone modification. Nucleic Acids Res. 38:1796-804.

6. Boulon S, Ahmad Y, Trinkle-Mulcahy L et al. (2010). Establishment of a protein frequency library and its application in the reliable identification of specific protein interaction partners. Mol Cell Proteomics. 9:861-79.

7. Schornack S, Fuchs R, Huitema E et al. (2009). Protein mislocalization in plant cells using a GFP-binding chromobody. Plant J. 60:744-54.

8. Fellinger K, Bultmann S, Rothbauer U et al. (2009). Np95 interacts with de novo DNA methyltransferases, Dnmt3a and Dnmt3b, and mediates epigenetic silencing of the viral CMV promoter in embryonic stem cells. EMBO Rep. 10:1259-64.

9. Muñoz IM, Hain K, Déclais AC et al. (2009). Coordination of structure-specific nucleases by human SLX4/BTBD12 is required for DNA repair. Mol Cell. 35:116-27.

10. Webby CJ, Wolf A, et al. (2009). Jmjd6 Catalyses Lysyl-Hydroxylation of U2AF65, a Protein Associated with RNA Splicing. Science. 325:90-93.

11. Rogowski K et al. (2009). Evolutionary divergence of enzymatic mechanisms for posttranslational polyglycylation. Cell. 137: 1076-87.

12. Frauer C, Leonhardt H, (2009) A versatile non-radioactive assay for DNA methyltransferase activity and DNA binding. Nucleic Acid Res. 35: 5402-5409.

13. Trinkle-Mulcahy L et al., (2008) Identifying specific protein interaction partners using quantitative mass spectrometry and bead proteomes. J Cell Biol. 183: s223-39.

14. Rothbauer U, Leonhardt H, (2008) Connecting Biochemistry and Cell Biology with Nanobodies. Zellbiologie aktuell 34: 9-12.

15. Rothbauer U et al., (2008) A versatile nanotrap for biochemical and functional studies with fluorescent fusion proteins. Mol Cell Proteomics 7: 282-289.

16. Agarwal N et al., (2007) MeCP2 interacts with HP1 and modulates its heterochromatin association during myogenic differentiation. Nucleic Acid Res.35: 5402-5409.

17. Rothbauer U et al., (2006) Targeting and tracing antigens in live cells with fluorescent nanobodies. Nat Methods 3: 887-889.

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Tags: anti-GFP, chromatin immunoprecipitation (ChIP), coIP, GFP, immunoprecipitation, nAb: Camelid Antibodies, Nanobodies, VHH, pull down

Your Feedback Helps Us Move Forward

It seems like every week Allele Biotech has a blog entry introducing a new product, or some cutting edge research. What is often overlooked is the driving force toward this innovation, and that force is you, the customer. As a company we work to make products that address our customer needs while maintaining competitive pricing.

In order to continue these practices we rely on customer feedback. What differentiates Allele Biotech from other companies is how we react to customer input, we use it to innovate. A great example of this is Allele Mouse Tail Lysis Buffer, a product we created at the request of a customer. This customer wanted an alternative to using phenol, a potentially hazardous chemical. We were able to create our buffer which works efficiently and effectively to lyse DNA safely. Today Mouse Tail Lysis Buffer is one of our top selling reagents, but we still love to hear back from our customers about it. Other examples of customer initiated products are our Cre Lentivirus, and our Protein extraction buffer. The Cre Lentivirus was requested to give the end user a high titer virus stock for applying Cre recombinase to their MEFS. Protein Extraction Buffer was created at the behest of a customer who wanted a low cost, but high quality alternative to B-Per.

So next time you are in lab and realize you need something, or can improve upon a product send us an email. If you are already using something from Allele let us know if the protocol is unclear, or if it’s too long. Tell us if it was an easy product to use, or if it was a tedious process that can be improved upon. We want to know that our products are working for you, and that you are satisfied with your purchase from Allele Biotech. With this back and forth between company and customer we can build the ideal client relationship.

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Tags: Baculo genomic DNA, cre, customer beedback, customer opinions, insect cell transfection, mouse tail genotyping, protein extraction