Leukemia Inhibitory Factor (LIF) is a lymphoid factor which promotes long-term maintenance of embryonic stem cells by suppressing spontaneous differentiation. LIF has a number of other activities including cholinergic neuron differentiation, control of stem cell pluripotency, bone and fat metabolism, mitogenesis of certain factor dependent cell lines and promotion of megakaryocyte production in vivo. Mouse LIF is a 22 kDa protein containing 203 amino acid residues.
mLIF is expressed in E. coli as a fusion protein with GST using the pGEX expression system, cleaved from GST moeity with thrombin and purified by HPLC chromatography.
5 μg, mouse recombinant LIF protein, expressed in E. coli, suitable for stem cell culture
RECOMMENDED QC PROTOCOL
1. The M1 bioassay is performed using in vitro semi-solid agar cultures, which contain approximately 100 cells in 1 mL volumes of DME containing 20 % FCS in 0.3% agar.
2. Add 100 μL of sample or mLIF (10(E4) units/mL in 5% FCS in isotonic saline) in two-fold serial dilutions in duplicate to 35 mm petri dishes.
3. Add 100 μL of 5% FCS in isotonic saline to two control slides.
4. Incubate at 37°C in fully humidified atmosphere of 10% CO2 in air for 7 days.
5. Score the number of colonies that show differentiation (note: 50 units is defined as the amount of activity which results in 50% of the colonies being differentiated).
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Manufactured by CHEMICON International, Inc. LIF is protected under US Patent nos. 5,443,825, 5,750,654 and 6,261,548, European Patent no. 0285 448 and related foreign patents and is not available for resale.
The specific activity is ≥1 x 10(E8) units/mg, where 50 units is defined as the amount of mouse LIF required to induce differentiation in 50% of the M1 colonies in 1 mL agar cultures.
Liquid in PBS, pH 7.4 and 0.02% Tween 20. No preservativies added.
Storage and Stability
Maintain at 2-8°C for 6 - 12 months. Further dilutions should be made into buffer or medium to which protein (e.g., 1% BSA) or Tween 20 has been added.
Manufactured by CHEMICON International, Inc. LIF is protected under US Patent
Tested negative in both aseptic and microplasmic tests.
The activity of mouse LIF is determined by the ability to induce differentiation of murine M1 myeloid leukemic cells. The minimum detectable concentration of mouse LIF in this assay is 0.5 ng/mL.
CHEMICON is a registered trademark of Merck KGaA, Darmstadt, Germany
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