ClonaCell™-TCS Medium is a serum-containing methylcellulose-based semi-solid medium that can be used for selecting and cloning a variety of suspension-adapted cell lines, including CHO-S and hybridomas. It can also be used for semi-solid cloning of some cell lines that grow adherently in the presence of serum, including CHO-K1, BHK-1, and HEK-293. This medium contains pre-selected fetal bovine serum (FBS) and bovine serum albumin (BSA) and supports robust growth of a wide variety of cell types. ClonaCell™-TCS Medium does not contain selection agents.
Benefits of semi-solid cloning:
• Individual cells are suspended in viscous medium and form physically separated, discrete colonies that are easily isolated.
• Monoclonal cell lines are isolated in less time using fewer resources compared with selection and cloning by limiting dilution.
• Diverse clones with a wide range of growth rates and productivities form discrete colonies in the viscous medium. As a result, rare and high-producing clones can be individually isolated more easily using simultaneous selection and cloning in semi-solid medium compared with selection in bulk liquid cultures.
• Supports high cloning efficiency and robust colony formation for a variety of cell lines such as: B16F-10, BaF/3, BHK-1, CHO-DG44, CHO-K1, CHO-S, FD-5, HEK-293, Jurkat Daudi, K562, Molt-4, UT-7
• IMDM (Iscove's Modified Dulbecco's Medium)
• Pre-selected serum
• Bovine serum albumin
• Phenol red
• Other ingredients
Semi-Solid Media, Specialized Media
CHO Cells, HEK-293, Hybridomas, Other
Cell Culture, Semi-Solid Cloning
Area of Interest
Antibody Development, Cell Line Development, Hybridoma Generation
Protocol for Cloning CHO Cell Lines Using ClonaCell™-CHO Semi-Solid Medium
Why Use Semi-Solid Medium for Cloning Hybridomas and CHO Cells
How to Perform Semi-Solid Cloning of CHO Cell Lines in 96-Well Plates Using ClonaCell™-CHO Medium
Semi-Solid Cloning of CHO Cells Using ClonaCell™-CHO Medium
Frequently Asked Question
Why do I get more cells when I select my fusion in liquid medium rather than in methylcellulose-based semi-solid medium?
Cells grown in liquid medium may appear to grow more rapidly than in methylcellulose-based medium. This is often due to the presence of a few rapidly growing clones that multiply quickly and become abundant in liquid culture, overgrowing clones that grow more slowly. In methylcellulose cultures, the rapidly growing cells remain in close proximity to each other, resulting in large colonies, each derived from a single fusion or transfection product. The large clones don't overgrow smaller, slower growing colonies, which can be separately isolated.
How do I thaw ClonaCell™ methylcellulose-based semi-solid medium?
We recommend thawing the medium overnight in a refrigerator at 4°C and mixing well.
How do I measure and dispense methylcellulose semi-solid medium?
We recommend using a 12 mL syringe with a 16 gauge needle attached (blunt end needles are recommended for safety purposes). Do not dispense the semi-solid media/cell mixture using serological pipettes as the media will stick to the pipette walls, resulting in inaccurate dispensed volumes and loss of cells.
My ClonaCell™ methylcellulose semi-solid medium appears runny. Why does this happen?
"Runny" methylcellulose could be a result of improper handling. Diluting the methylcellulose with too much liquid medium, or insufficient mixing before use, will result in methylcellulose with altered viscosity. Excessive condensation on the inside of the cell culture dish lid can result in water dripping onto the cultures, lowering viscosity. Additionally, bumping, shaking or other sudden movement of the culture may also disrupt the colonies. Note: methylcellulose is less viscous at room temperature than at 37°C.
What is the optimal number of colonies per plate?
We recommend 50-150 colonies per plate. As it is difficult to anticipate the numbers of colonies after a fusion or transfection, we recommend plating at three different densities to increase the likelihood of achieving a plating density of approximately 100 colonies per plate. This density allows sufficient space between the colonies to allow for easy colony picking.
There are still bubbles in the media after I plate my cells. Do I need to disrupt the bubbles?
We recommend that you avoid creating large bubbles during plating, but there is no need to manually pop or disperse the small bubbles after plating. They will disperse over the incubation period of 10-14 days.
Do I ever need to re-clone cultures grown with ClonaCell™ semi-solid medium?
Re-cloning is a good practice to observe and is recommended if the number of colonies in the original dishes was very high.
Once I pick the colonies and grow the cells in plates, will the residual methylcellulose interfere with characterization? For example, will I have problems doing an ELISA?
There will likely be some residual methylcellulose contamination when colonies are picked and transferred to the 96-well plate with the liquid growth medium. The concentration of methylcellulose, however, should be low enough that it should not interfere with most assays.
How important is the incubator humidity when culturing in methylcellulose-based medium?
Very important. In situations where the humidity is not high enough, we recommend that the 100 mm Petri dishes should be placed with an open dish containing sterile water inside a larger plastic container with a lid. Without very high humidity, the media will dry out over the culture period and this will impede the growth of the colonies.
Do I have to use 100 mm petri dishes or can I use other cultureware?
We recommend 100 mm Petri dishes as these have been used to develop and test ClonaCell™ semi-solid media. We have found that the surface area of these dishes allows for easy colony picking. Other sizes of dish (e.g. 6-well plates) can be used. It is important to use non-coated dishes to prevent cells from sticking to the bottom of the plate and obscuring the colonies. The volume of media plated should be adjusted to reflect the surface area of the dish being used.
Is the serum in ClonaCell™-TCS medium heat inactivated?
Yes, all serum used in ClonaCell™ is heat inactivated.
Is there any IgG in ClonaCell™ TCS?
While we don't add IgG to the ClonaCell™ media, we do add serum, which contains an undefined amount of IgG. We selectively use serum lots with low IgG levels in the production of ClonaCell™ media, however, levels vary from lot to lot. IgG levels in a specific lot of ClonaCell™ TCS medium are available in the lot-specific Certificate of Analysis.
Can ClonaCell™-TCS be used with any cell line?
A list of recommended cell lines can be found in the manual. Other cell lines may be compatible with ClonaCell™-TCS. It will be necessary, however, to determine the plating cell density and growth efficiency of the desired cells in ClonaCell™-TCS.
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Several somatic ribosome defects have recently been discovered in cancer, yet their oncogenic mechanisms remain poorly understood. Here we investigated the pathogenic role of the recurrent R98S mutation in ribosomal protein L10 (RPL10 R98S) found in T-cell acute lymphoblastic leukemia (T-ALL). The JAK-STAT signaling pathway is a critical controller of cellular proliferation and survival. A proteome screen revealed overexpression of several Jak-Stat signaling proteins in engineered RPL10 R98S mouse lymphoid cells, which we confirmed in hematopoietic cells from transgenic Rpl10 R98S mice and T-ALL xenograft samples. RPL10 R98S expressing cells displayed JAK-STAT pathway hyper-activation upon cytokine stimulation, as well as increased sensitivity to clinically used JAK-STAT inhibitors like pimozide. A mutually exclusive mutation pattern between RPL10 R98S and JAK-STAT mutations in T-ALL patients further suggests that RPL10 R98S functionally mimics JAK-STAT activation. Mechanistically, besides transcriptional changes, RPL10 R98S caused reduction of apparent programmed ribosomal frameshifting at several ribosomal frameshift signals in mouse and human Jak-Stat genes, as well as decreased Jak1 degradation. Of further medical interest, RPL10 R98S cells showed reduced proteasome activity and enhanced sensitivity to clinical proteasome inhibitors. Collectively, we describe modulation of the JAK-STAT cascade as a novel cancer-promoting activity of a ribosomal mutation, and expand the relevance of this cascade in leukemia.
Nature Medicine 2016 NOV
DNMT3A mutations promote anthracycline resistance in acute myeloid leukemia via impaired nucleosome remodeling.
Guryanova OA et al.
Although the majority of patients with acute myeloid leukemia (AML) initially respond to chemotherapy, many of them subsequently relapse, and the mechanistic basis for AML persistence following chemotherapy has not been determined. Recurrent somatic mutations in DNA methyltransferase 3A (DNMT3A), most frequently at arginine 882 (DNMT3A(R882)), have been observed in AML and in individuals with clonal hematopoiesis in the absence of leukemic transformation. Patients with DNMT3A(R882) AML have an inferior outcome when treated with standard-dose daunorubicin-based induction chemotherapy, suggesting that DNMT3A(R882) cells persist and drive relapse. We found that Dnmt3a mutations induced hematopoietic stem cell expansion, cooperated with mutations in the FMS-like tyrosine kinase 3 gene (Flt3(ITD)) and the nucleophosmin gene (Npm1(c)) to induce AML in vivo, and promoted resistance to anthracycline chemotherapy. In patients with AML, the presence of DNMT3A(R882) mutations predicts minimal residual disease, underscoring their role in AML chemoresistance. DNMT3A(R882) cells showed impaired nucleosome eviction and chromatin remodeling in response to anthracycline treatment, which resulted from attenuated recruitment of histone chaperone SPT-16 following anthracycline exposure. This defect led to an inability to sense and repair DNA torsional stress, which resulted in increased mutagenesis. Our findings identify a crucial role for DNMT3A(R882) mutations in driving AML chemoresistance and highlight the importance of chromatin remodeling in response to cytotoxic chemotherapy.
Leukemia 2016 MAR
Generation of the Fip1l1–Pdgfra fusion gene using CRISPR/Cas genome editing
Vanden Bempt M et al.
BACKGROUND The ability to site-specifically conjugate a protein to a payload of interest (e.g., a fluorophore, small molecule pharmacophore, oligonucleotide, or other protein) has found widespread application in basic research and drug development. For example, antibody-drug conjugates represent a class of biotherapeutics that couple the targeting specificity of an antibody with the chemotherapeutic potency of a small molecule drug. While first generation antibody-drug conjugates (ADCs) used random conjugation approaches, next-generation ADCs are employing site-specific conjugation. A facile way to generate site-specific protein conjugates is via the aldehyde tag technology, where a five amino acid consensus sequence (CXPXR) is genetically encoded into the protein of interest at the desired location. During protein expression, the Cys residue within this consensus sequence can be recognized by ectopically-expressed formylglycine generating enzyme (FGE), which converts the Cys to a formylglycine (fGly) residue. The latter bears an aldehyde functional group that serves as a chemical handle for subsequent conjugation. RESULTS The yield of Cys conversion to fGly during protein production can be variable and is highly dependent on culture conditions. We set out to achieve consistently high yields by modulating culture conditions to maximize FGE activity within the cell. We recently showed that FGE is a copper-dependent oxidase that binds copper in a stoichiometric fashion and uses it to activate oxygen, driving enzymatic turnover. Building upon that work, here we show that by supplementing cell culture media with copper we can routinely reach high yields of highly converted protein. We demonstrate that cells incorporate copper from the media into FGE, which results in increased specific activity of the enzyme. The amount of copper required is compatible with large scale cell culture, as demonstrated in fed-batch cell cultures with antibody titers of 5 g textperiodcentered L(-1), specific cellular production rates of 75 pg textperiodcentered cell(-1) textperiodcentered d(-1), and fGly conversion yields of 95-98 %. CONCLUSIONS We describe a process with a high yield of site-specific formylglycine (fGly) generation during monoclonal antibody production in CHO cells. The conversion of Cys to fGly depends upon the activity of FGE, which can be ensured by supplementing the culture media with 50 uM copper(II) sulfate.
Generation of recombinant modified Vaccinia Virus Ankara encoding VP2, NS1, and VP7 proteins of bluetongue virus
Marí et al.
Modified Vaccinia Virus Ankara (MVA) is employed widely as an experimental vaccine vector for its lack of replication in mammalian cells and high expression level of foreign/heterologous genes. Recombinant MVAs (rMVAs) are used as platforms for protein production as well as vectors to generate vaccines against a high number of infectious diseases and other pathologies. The portrait of the virus combines desirable elements such as high-level biological safety, the ability to activate appropriate innate immune mediators upon vaccination, and the capacity to deliver substantial amounts of heterologous antigens. Recombinant MVAs encoding proteins of bluetongue virus (BTV), an Orbivirus that infects domestic and wild ruminants transmitted by biting midges of the Culicoides species, are excellent vaccine candidates against this virus. In this chapter we describe the methods for the generation of rMVAs encoding VP2, NS1, and VP7 proteins of bluetongue virus as a model example for orbiviruses. The protocols included cover the cloning of VP2, NS1, and VP7 BTV-4 genes in a transfer plasmid, the construction of recombinant MVAs, the titration of virus working stocks and the protein expression analysis by immunofluorescence and radiolabeling of rMVA infected cells as well as virus purification.
Molecular Cancer 2015 DEC
Long noncoding RNA, CCDC26, controls myeloid leukemia cell growth through regulation of KIT expression
Hirano T et al.
BACKGROUND Accumulating evidence suggests that some long noncoding RNAs (lncRNAs) are involved in certain diseases, such as cancer. The lncRNA, CCDC26, is related to childhood acute myeloid leukemia (AML) because its copy number is altered in AML patients. RESULTS We found that CCDC26 transcripts were abundant in the nuclear fraction of K562 human myeloid leukemia cells. To examine the function of CCDC26, gene knockdown (KD) was performed using short hairpin RNAs (shRNAs), and four KD clones, in which CCDC26 expression was suppressed to 1% of its normal level, were isolated. This down-regulation included suppression of CCDC26 intron-containing transcripts (the CCDC26 precursor mRNA), indicating that transcriptional gene suppression (TGS), not post-transcriptional suppression, was occurring. The shRNA targeting one of the two CCDC26 splice variants also suppressed the other splice variant, which is further evidence for TGS. Growth rates of KD clones were reduced compared with non-KD control cells in media containing normal or high serum concentrations. In contrast, enhanced growth rates in media containing much lower serum concentrations and increased survival periods after serum withdrawal were observed for KD clones. DNA microarray and quantitative polymerase chain reaction screening for differentially expressed genes between KD clones and non-KD control cells revealed significant up-regulation of the tyrosine kinase receptor, KIT, hyperactive mutations of which are often found in AML. Treatment of KD clones with ISCK03, a KIT-specific inhibitor, eliminated the increased survival of KD clones in the absence of serum. CONCLUSIONS We suggest that CCDC26 controls growth of myeloid leukemia cells through regulation of KIT expression. A KIT inhibitor might be an effective treatment against the forms of AML in which CCDC26 is altered.
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