Technote | FGF-8a (Qk059)

Highly bioactive animal-free Fibroblast Growth Factor 8a


Fibroblast growth factor 8a (FGF-8a) is a spliced form of FGF8, a member of the FGF family. FGF-8a plays a crucial role in regulating embryonic development and is involved in the proliferation, differentiation, and migration of induced pluripotent, embryonic, and neural stem cells. For stem cell cultures, animal-free growth factors are preferable in comparison to mammalian-expressed growth factors which have more risks of batch-to-batch variability and contamination from animal-derived ingredients. Qkine FGF-8a is expressed in E. coli to ensure the bioactivity is reliable. 


The bioactivity of Qk059 FGF-8a and mammalian-expressed FGF-8a from an alternative supplier was determined using the Promega serum response element luciferase reporter assay in HEK293T cells. Cells were treated in triplicate with a serial dilution of FGF-8a in the presence of 10 µg/mL heparin for 3 hours. Firefly luciferase activity was measured and normalized to the control Renilla luciferase activity.  


The bioactivity comparison between Qkine FGF-8a and FGF-8a from an alternative supplier showed that Qkine FGF-8a protein has a higher bioactivity than the mammalianexpressed growth factor. Qkine FGF-8a offers an alternative animal-free protein expressed in E. coli with high bioactivity suitable for neural stem cell culture and FGF-8a-dependent applications.  

Quantitative luciferase reporter assay shows FGF-8a (Qk059, green) has a higher bioactivity with an EC50 of 108.1 ng/mL (5 nM) compared to mammalian-expressed FGF-8a (Supplier 1, black) with an EC50 of 567 ng/mL (27 nM). Data for Qk059 lot #104406. 

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