Haemophilia A: database of nucleotide substitutions, deletions, insertions and rearrangements of the factor VIII gene, second edition

Proposed structure of the A domains of factor VIII by homology modelling

We have predicted a structure for the three A domains of blood coagulation factor VIII by virtue of their homology to blue copper-binding proteins. This structure, consisting of six beta-barrels, is arranged in a triangular configuration with a single type II copper-binding site linking the A1 and A3 domains.

The effect of endogenous oestradiol levels on protein S concentration during a menstrual cycle and after GnRH analogues and gonadotropin therapy

We studied two groups of females to investigate the effect of endogenous oestradiol levels on total and free protein S (tPS, fPS) plasma concentrations. One group (group I) consisted of 12 healthy volunteers who were studied throughout one menstrual cycle; the other group (group II) consisted of 16 young women who were treated with GnRH analogues and gonadotropins before undergoing in vitro fertilization. Neither tPS nor fPS varied significantly with respect to the physiological changes of oestradiol or to the very low and high levels of oestradiol, achieved after GnRH analogues suppression and gonadotropin stimulation. These results indicate that endogenous oestradiol does not affect PS concentration.

cis-acting elements and transcription factors involved in the promoter activity of the human factor VIII gene

Factor VIII is a glycoprotein that is essential for blood coagulation. Although factor VIII mRNA has been detected in a variety of human tissues, hepatocytes are considered to be the major source of plasma factor VIII. In this report we demonstrate that the 5'-flanking region of the factor VIII gene is able to transcribe a luciferase reporter gene in three human liver-derived cell lines: PLC/PRF/5, Chang, and HepG2. DNase I footprinting showed the presence of 19 protein binding sites (labeled A to S, proximal to distal) distributed along the region from nucleotide -1175 to -9 of the factor VIII promoter (+1 refers to the translation initiation codon, ATG). Functional analysis of 5' and 3' deletion mutants of the promoter region in PLC/PRF/5 cells revealed that the region from -279 to -64, including sites B to D, contains all the necessary elements for maximal promoter activity. By using electrophoretic mobility shift assays with nuclear extracts and purified transcription factors, and antibody supershift assays we were able to characterize four liver-enriched factors and one ubiquitous transcription factor interacting with the proximal promoter binding sites (sites A to E): hepatocyte nuclear factor (HNF) 1 (site A), NF kappa B (site B), C/EBP alpha and C/EBP beta (proximal and distal regions of site C, and site D), and HNF4 (site E). Additionally, mutation of the putative TATA box GATAAA (positions -201 to -196) to GACCGA resulted in less than 2-fold decrease in promoter activity, suggesting that the putative TATA box is not essential for factor VIII promoter activity. These results significantly contribute to the understanding of the control of the hepatic transcription of the factor VIII gene.

Detection of mutations in ectopic factor VIII transcripts from nine haemophilia A patients and the correlation with phenotype

Haemophilia A is a common X-linked recessive disorder of bleeding caused by deleterious mutations in the gene for clotting factor VIII. The large size of the factor VIII gene, the high frequency of de novo mutations and its tissue-specific expression complicate the detection of mutations. We have used a combination of reverse transcription/polymerase chain reaction (RT-PCR) of ectopic factor VIII transcripts and PCR of genomic DNA to amplify the entire essential sequence of the factor VIII gene. Chemical mismatch cleavage analysis and direct sequencing have then be employed in order to facilitate a comprehensive search for mutations. In this report, we describe the characterisation of nine potentially pathogenic mutations, six of which are novel. The mutations include six single base substitutions (five missense, viz. D56E, V162M, G701D, A1834T and R1869I, and one nonsense, viz. R-5X), a single base deletion (5697delC), a gross deletion of exon 16 and one mRNA abnormality characteristic of the common intron-22-embedded F8A-mediated DNA inversion. In each case, a correlation of the genotype with the observed phenotype is presented. In order to evaluate the pathogenicity of the five missense mutations, we have analysed them for evolutionary sequence conservation and for their involvement with sequence motifs catalogued in the PROSITE database of protein sites and patterns. Analysis of the sequences in the immediate vicinity of the mutations has revealed sequence features that may have had a possible role in mutagenesis.