How do you produce your iPS cells?

From AlleleForum: First off, thank you for choosing Allele Biotech for your iPSC experiment needs. Now onto your questions

You asked Q1: How many human fibroblast cells you normally to start for transfection. I understand you use 12-well plate? How many days you wait till the cells grow confluent? If the cells never grow confluent, should I still transfer them to feeder plate? Is it critical for the cells to reach confluent, if it is, could you suggest the reasons to me

We usually plate at 70% or about 10e4-10e5 cells and transduce the cells for 2-3 days. It should become confluent in 2-3 days. There is no need for the cells to become confluent before splitting onto feeder cells. Please note for primary cells, do not wait for the cells to get too confluent because contact inhibition may induce growth senescence before cells are reprogrammed.

Q2: How many cells you plate on the feeder plate, let’s say it is 6-well plate, and how many clones would normally pup out from each well?

From one well of a 12 well plate, you can plate 1/5 onto a well of a 6 well feeder cell plate. From there, you should get plenty of colonies.

Q3: At the time when you need to cut the Loxp sites, what passage number you do, do you have to dispense the iPS into single cell? Do you have a detailed protocol for that? Other than virus, do you have any other means to do the job, like plasmid?

Never dispense iPSC into single cells. They do not grow back well if split into single cells. iPSC colonies should be passaged in patches of cells. To excise loxP, the suggested timing is after 12-14 days when the cells are reprogrammed into iPSC colonies. Just transduce the iPSC colonies with Cre virus.

Q4: Is it true, that the 4-in-1 is more powerful than individual ones? Do you have the construct(4-in-one) for sale?

The 4-in-1 is somewhat more effective than 4 individual ones. For license issues, we do not distribute the construct to customers because we only offer packaging service. Similar type of plasmid DNAs may be accessible from other sources.

If you have any other questions or concerns, please let us know. Thanks again.

New Product of the Week 082310-082910:

pInman-iPS Bac2Mam viruses, email iPS@allelebiotech.com for details.

Promotion of the Week 082310-082910:

Thomson set of iPS vectors on lentivirus, send in order this week get 20% discount. Email iPS@allelebiotech.com for details, with promotion code V082910.

Tags: 4-in-1, feeder cells, iPS, iPS colonies, iPS medium, iPS protocol, lentivirus, loxP Cre, splitting iPS cells

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.

New Product of the Week

080210-080810: mTFP1-Mitochondria-neoR plasmid, a new drug-resistant version of Allele’s organelle markers

Promotion of the Week

080210-080810: Retroviruses expressing OSKM or OSNL set of iPS factors at $500 for order placed this week only for all Allele Facebook fans, others with code iPS0808 mentioned in order.

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!

Ain't they pretty?

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 mWasabi is stimulating

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

The LanFPs express well in bacteria.

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.

Can you see the FP bands in the SDS PAGE?

FPs in SDS PAGE–a closer look

Can you see them now?

FPs in gel cassette over UV lights

Invincible FPs

FPs in gel cassette under blue LED

Fluorescence in SDS page under blue LED

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

New Product of the Week 07/26/10-08/01/10: pCHAC-mWasabi-C for expressing mWasabi fusion through retroviral vectors.

Promotion of the Week 07/26/10-08/01/10: Get 3′ TAMRA & BHQ oligo mods for $45 ea & 3′ Dabcyl mod for $20 50 nmol syn scale only/while supplies last- use dbtkrm0726

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

Lentiviruses expressing constitutively active or dominant negative versions of genes in signaling pathways

NF-kB (nuclear factor kappa-light-chain-enhancer of activated B cells) refers to a protein complex functional in signaling pathways, particularly in response to stress stimuli. There are two signaling pathways leading to the activation of NF-kB signaling, known as the canonical (or classical) pathway, the non-canonical (or alternative) pathway.

In the canonical NF-kB pathway, NF-kB dimers such as p50/RelA are maintained in the cytoplasm by interaction with an independent Inhibitor of NF-kB (IkB) molecule. When the upstream signaling is active, an IkBa kinase (IKK) complex consisting of catalytic kinase subunits IKKa and/or IKKb and the scaffold protein NEMO will be recruited to the cytoplasmic adaptor of certain cell surface receptor and stay activated. Activation of IKK complex will consequently phosphorylate the IkB at two serine residues, which induce the proteasomal degradation of IkB. Released from IkB, NF-kB dimers then translocate into the nucleus and bind with a consensus sequence (GGGACTTTCC) of various genes and thereby activates their transcription. In a negative feedback loop, NF-kB activation also leads to the expression of the IkB gene, which subsequently sequesters NF-kB subunits and terminates transcriptional activity unless a constitutive activation signal is present.

The non-canonical pathway is mainly for activation of p100/RelB complexes during B-and T-cell development, where NF-kB was first discovered. Different from the canonical pathway, 1) only certain receptor signals (e.g., Lymphotoxin B, B-cell activating factor, CD40) can activate this pathway, 2) it proceeds through an IKK complex that contains two IKKa subunits (but not NEMO) and 3) receptor binding leads to activation of the NF-kB-inducing kinase NIK, which phosphorylates and activates an IKKa complex, the latter in turn phosphorylates two serine residues adjacent to the ankyrin repeat C-terminal IkB domain of p100, leading to its partial proteolysis and liberation of the p52/RelB complex.

Other distinct NF-kB pathways undoubtedly exist. For example, p50 (or p52) homodimers enter the nucleus, where they become transcriptional activators by virtue of interaction with the IkB-like co-activator Bcl-3 (or IkBz). How these are regulated is not known.

There are many ways of applying reagents that can manipulate the NF-kB system for drug screening as well as basic research. For this reason, Allele Biotech is introducing a set of lentiviruses as listed below. The way this product group is operated is that the Allele will publish the design and specifics of the products, but will produce it upon the first order. The person who places the first order will need to wait for 3-5 weeks for receiving the products, but will receive a 40% discount and an opportunity to provide input to the product design. The platform for lentiviral products is based on our field-leading high titer lentivirus packaging capabilities, and you can rest assured that high quality lentivirus will be produced at a pace much faster and lower price than if you were to make them by your own lab or find them from anywhere else. Allele Biotech will introduce more such products in the fields of miRNA (to provide all ~800 human miRNA and their anti-miRNA silencers on virus), cell differentiation lineage-specific promoter-FP reporters, etc. We now call these products the Lead Products. Cost effectiveness is just the beginning. Imagine how our ingenuity and innovation can pave the way for your research.

1) HiTiter IkBa Expression Lentiviral Particles: can be used in functional studies of IkBa’s roles in NF-kB signaling. Overexpression of IkBa will eliminate the low-level activation by factors in the cell culture medium or other fluctuations to ensure that any change in NF-kB signaling is caused by the stimulus being tested.
2) HiTiter Dominant Negative IkBa Expression Lentiviral Particles: Dominant Negative IkBa has serine-to-alanine changes at residues 32 and 36. It can be used to repress the expression of endogenous IkBa or block NFkB signaling in certain cell lines.
3) HiTiter IkBa-RFP Fusion Expression Lentiviral Particles: This is a reporter suitable for the studying proteasomal degradation of IkBa after phosphorylation.

4) HiTiter IKKa Expression Lentiviral Particles: can be used in functional research for the role of IKKa in NF-kB signaling.
5) HiTiter Constitutively Active IKKa Expression Lentiviral Particles: Constitutively active IKKa has serine-to-glutamate mutations at residues 176 and 180.
6) HiTiter Dominant Negative IKKa Expression Lentiviral Particles: Dominant negative IKKa is mutated by serine-to-alanine at residues 176 and 180.
7) HiTiter IKKb Expression Lentiviral Particles: can be used in functional research for the role of IKKb in NF-kB signaling.
8) HiTiter Constitutively Active IKKb Expression Lentiviral Particles: Dominant negative IKKb is mutated by serine-to-glutamate at residues 177 and 181.
9) HiTiter Dominant Negative IKKb Expression Lentiviral Particles: Dominant negative IKKb is mutated by serine-to-alanine at residues 177 and 181.
10) HiTiter pNFkB-Luciferase Lentiviral Particles: a cis-reporter plasmid containing the luciferase reporter cDNA linked to five repeats of an NF-kB binding site.
11) HiTiter pNFkB-GFP Lentiviral Particles: a cis-reporter plasmid containing the GFP reporter gene linked to five repeats of an NF-kB binding site.

New Product of the Week 05-23-10 to 05-31-10:

Cre recombinase fused to mWasabi GFP carried on lentivirus, ABP-RP-Cre2AGL, or ABP-RP-Cre2AGS

Promotion of the week 05-23-10 to 05-31-10:

actually 3 promotions this week, first announced to Allele fans and friends on Facebook: 10% off the brand-new RFP-Trap ACT-CM-RFA0050 for co-IP with mCherry, mPlum, mOrange…Order by Monday to qualify for discount! Free sample for FAM-amidite for oligo cores at universities that make qPCR and other probes. Free sample of high attachment tissue culture plates that use 40% less plastics (made in Canada)

Tags: Bcl-3, drug screening, IkBa, IkBz, Ikka, Ikkb, lentivirus, NEMO, NF-kB, p100, p50/RelA, p52/RelB, signaling pathways, stimuli, stimulus

Take Advantage of Allele’s Essential Virus Grant Program, Have High Titer Virus for Your Research on Essential Human Genes

The number of Allele products in the form of viral particles is increasing quickly. Most of these products are also listed under product groups categorized according to their respective functions (e.g. iPS production under “Induced Pluripotent Stem Cells”, shRNA under “RNA Interference”, cytokines and enzymes under “Recombinant Proteins”). Additional background information, as well as related products, may be found on the landing pages of each product group.

The increase in scientific publications reporting the conversion of “dormant” genes into “active” ones has resulted in a significant demand for cDNA clones, antibodies, expression vectors, etc., all in short order. Providing reagents for the expansion of research on such genes is scientifically important and potentially rewarding if the market catches up. Allele Biotech works diligently to supply the most up-to-date and active researchers with pre-validated viral particles for expressing many of these “hot” genes, (e.g. iPS factors, light-activated ion channels, factors that induce neuronal cells from other cell types). Allele Biotech produces custom-packaged high titer lentivirus and retrovirus using unique technologies, as described under “Services by Category”-> “Viral Packaging”.
Under the Essential Virus Grant Program, Allele Biotech accepts custom viral packaging orders, including cDNA of shRNAs against recently established critical mammalian factors. The process begins with an evaluation of your one page application explaining why the factor can potentially be in demand by other researchers. If the application is accepted, Allele Biotech will waive the charges for the project and consider it an R&D effort. Allele Biotech will also offer it as a shelf product at a much lower cost than custom projects. Interested researchers please submit your applications with your order; our accounting department will promptly forward your request to our review group.

New Product of the Week 05-03-10 to 05-09-10: Essential Virus Grant Program

Promotion of the Week 05-03-10 to 05-09-10: for a limited time, pre-packaged, validated IL2 and IL15 lentiviruses. http://www.allelebiotech.com/shopcart/index.php?c=206&sc=0

Tags: cDNA, essential genes, lentivirus, miRNA, promoter reporter, virus packaging