Human coagulation factor VIII domain-specific recombinant polypeptide expression

BACKGROUND: Hemophilia A is caused by heterogeneous mutations in F8. Coagulation factor VIII (FVIII), the product of F8, is composed of multiple domains designated A1-A2-B-A3-C1-C2. FVIII is known to interact with diverse proteins, and this characteristic may be important for hemostasis. However, little is known about domain-specific functions or their specific binding partners. METHODS: To determine F8 domain-specific functions during blood coagulation, the FVIII domains A1, A2, A3, and C were cloned from Hep3B hepatocytes. Domain-specific recombinant polypeptides were glutathione S-transferase (GST)- or polyhistidine (His)-tagged, over-expressed in bacteria, and purified by specific affinity chromatography. RESULTS: Recombinant polypeptides of predicted sizes were obtained. The GST-tagged A2 polypeptide interacted with coagulation factor IX, which is known to bind the A2 domain of activated FVIII. CONCLUSION: Recombinant, domain-specific polypeptides are useful tools to study the domain-specific functions of FVIII during the coagulation process, and they may be used for production of domain-specific antibodies.

Identification of a shared F8 mutation in the Korean patients with acquired hemophilia A

Although uncommon, acquired hemophilia A (HA) is associated with a high rate of mortality due to severe bleeding. In spite of many hypotheses regarding the cause of acquired HA, there is as yet no established theory. In this study, we investigated the possibility that mutation(s) in the F8 gene may be correlated with the development of inhibitory autoantibodies. Direct sequencing analysis was performed on all 26 exons of the F8 gene of 2 patients exhibiting acquired HA. Both patients were found to share a common point mutation (c.8899G>A) in the 3'-untranslated region (3'-UTR) of exon 26. This is the first report on the genotyping of F8 in the context of acquired HA.