Structure of the Human Factor VII Gene

1987 ◽  
Author(s):  
Patrick J O'hara ◽  
Frank A Grant ◽  
A Betty ◽  
J Haldmen ◽  
Mark J Murray
Keyword(s):  
Serine Protease ◽  
Vitamin K ◽  
Protein C ◽  
Tandem Repeats ◽  
Human Factor ◽  
Factor Ix ◽  
Factor Vii ◽  
Factor X ◽  
X Protein ◽  
Additional Exon

Factor VII is a member of a family of vitamin K-dependent, gamma-carboxylated plasma protein which includes factor IX, factor X, protein C, protein S and prothrombin. Activated factor VII (factor Vila) is a plasma serine protease which participates in a cascade of reactions leading to the coagulation of blood. Two overlapping genomic clones containing sequences encoding human factor VII were isolated and characterized. The complete sequence of the gene was determined and found to span 12.8 kilobases. The mRNA for factor VII as demonstrated by cDNA cloning is polyadenylated at multiple sites but contains only one AAUAAA poly-A signal sequence. The mRNA can undergo alternative splicing forming one transcript containing eight segments as exons and another with an additional exon which encodes a larger pre-pro leader sequence. The portion of the pre-pro leader coded for by the additional exon has no known counterpart in the other vitamin K-dependent proteins. The positions of the introns with respect to the amino acid sequence encoded by the eight essential exons of factor VII are the same as those present in factor IX, factor X, protein C and the first three exons of prothrombin. These exons code for domains generally conserved among members of this gene family, including a pre-pro leader (the essential exon la and alternative exon lb), a gamma-carboxylated domain (exons 2 and 3) a growth factor domain (exons 4 and 5) an activation region (exon 6) and a serine protease (exon 8). The corresponding introns in these genes are dissimilar with respect to size and sequence, with the exception of the third intron in factor VII and protein C. Four introns and a portion of exon 8 in factor VII contain regions made up of tandem repeats of oligonucleotide monomer elements. More than a quarter of the intron sequences and more than a third of the 3' untranslated portion of the mRNA transcript consist of these minisatellite tandem repeats. This type of structure is responsible for polymorphisms due to allelic variation in repeat copy number in other areas of the human genome. Tandem repeats can evolve as a result of random crossover in DNA whose sequence is not maintained by selection. This suggests that much of the sequence information present in the introns and untranslated portion of the message is dispensable.

The Activation of Human Factor X in Sodium Citrate: the Role of Factor VII

1976 ◽  
Vol 36 (01) ◽  
pp. 104-114 ◽  
Author(s):  
D. L Aronson ◽  
A. J Mustafa
Keyword(s):  
Sodium Citrate ◽  
Human Factor ◽  
Deae Cellulose ◽  
Factor Ix ◽  
Factor Vii ◽  
Factor X

SummaryHuman factor X was purified by several different procedures yielding products which had varying amounts of factor VII and factor IX. Treatment with CHC13 during the fractionation of the factor X removed 95% of the factor VII and factor IX activity and the resulting factor X activated more slowly when incubated in 25% sodium citrate. Removal of residual factor VII by DEAE cellulose chromatography yielded a factor X which activated still more slowly and less completely. When the factor VII, removed by chromatography, was added to the chromatographed factor X, the ability to be activated in 25% sodium citrate was restored. Confirmatory evidence for the role of factor VII in this reaction was the inhibition of the conversion of the factor X by both DFP and SBTI.

The Inhibitor of Prothrombin Conversion in Plasma of Patients on Oral Anticoagulant Treatment

1981 ◽  
Vol 45 (03) ◽  
pp. 237-241 ◽  
Author(s):  
R M Bertina ◽  
M E J Westhoek-Kuipers ◽  
G H J Alderkamp
Keyword(s):  
Vitamin K ◽  
Spectrophotometric Assay ◽  
Factor Ix ◽  
Factor Vii ◽  
Factor X ◽  
Dilution Curve ◽  
Anticoagulant Treatment ◽  
Oral Anticoagulant Treatment ◽  
Coagulation Assays ◽  
Factor Ii

SummaryPooled plasma of patients under stable oral anticoagulation has been analysed with respect to the presence of the vitamin-K dependent factors (factors II, VII, IX and X). Of all factors 1.5-2 times more antigen than procoagulant activity was present. The concentration of factors II, X (measured spectrophotometrically) and VII is about 0.25 U/ml while factor IX is slightly higher. Coagulation assays of factor X always gave lower values than the spectrophotometric assay. This discrepancy was not influenced by the removal of either factor II-factor VII- or factor IX antigen. However, when the factor X antigen was replaced by normal factor X, all factor X assays gave identical results, indicating that PIVKA X is responsible for these discrepancies. Using the technic of the Thrombotest-dilution curve it was shown that PIVKA X is the factor that causes the abnormal prolongation of ox-brain prothrombin time in these plasmas.

ACUTE INTERRUPTION OF ORAL ANTICOAGULANT THERAPY: A THROMBOTIC RISK?

1987 ◽  
Author(s):  
J Rouvier ◽  
H Vidal ◽  
J Gallino ◽  
M Boccia ◽  
A Scazziota ◽  
...  
Keyword(s):  
Anticoagulant Therapy ◽  
Vitamin K ◽  
Oral Anticoagulant ◽  
Protein C ◽  
Oral Anticoagulant Therapy ◽  
Factor Vii ◽  
Factor X ◽  
Functional Protein ◽  
Thrombotic Risk ◽  
Factor Ii

It is still on discussion how oral anticoagulant therapy must be interrupted. A progressive diminution of drug intake have been proposed in order to avoid a MreboundM of vitamin K-dependent procoagulant factors. At the present, it is well known that coumarin drugs affect not only the biologic activity of factors II, VII, IX and X but also Protein C (PC), an inhibitor of coagulation kinetics, and their cofactor Protein S. With the aim to determine the recovery level of PC in relation with the others vitamin K-dependent factors, the effect of suppression of anticoagulant therapy in patients under chronic treatment with acenocoumarin was studied.Quick time, functional factors II, VII, X (one stage methods), functional PC (Francis method) and immunological Factor II and Protein C (Laurell) were determined before and 36 hours after suspension of acenocoumarin administration.Results showed that: 1) Recovery levels of functional Protein C (increased from 28.55% ±2.57 to 72.64% ±5.9) were significantly higer than functional Factor II (22.09% ±2.34 to 30.73% ±8.64), Factor VII (22.55% ±2.01 to 40.73% ±4.85) and Factor X (23.27% ±2.66 to 39.18% ±3.19). Statistical analysis (Newmann-Keuls test) showed at least a p<0.01 between PC increase and factors II, VII or X increment.2) No significant differences were seen between immunological levels of Factor II before and after suspension of acenocoumarin.3) Levels of immunological PC in patients under anticoagulant therapy were higer than functional PC. After acenocoumarin suppression, not correlation was seen between immunological and functional Protein C recovery.It is concluded that acute suppression of acenocoumarin does not induce a thrombotic tendency because the recuperation of functional Protein C is more important than factors II, VII and X recovery.

Activation Of Human Factor VII By Activated Factors IX And X In Purified Systems

1981 ◽  
Author(s):  
D R Masys ◽  
S P Bajaj ◽  
S I Rapaport
Keyword(s):  
Gel Electrophoresis ◽  
Relative Efficiency ◽  
Human Factor ◽  
Polyacrylamide Gel Electrophoresis ◽  
Factor Ix ◽  
Factor Vii ◽  
Activate Factor ◽  
Factor X ◽  
One Stage ◽  
Amplification Loop

Factor VII activity, as measured in a one-stage clotting assay, increases when whole blood is clotted in glass. Prior studies in this laboratory using factor-deficient plasmas suggested that this factor VII activation was due to activated factor IX (IXa). We therefore studied activation of VII by IXa and by activated factor X (Xa) in purified systems. Human factors II, VII, IX, and X were each purified to homogeneity as judged by SDS-polyacrylamide gel electrophoresis. Reaction mixtures of VII, IXa or Xa, and other cofactors and enzymes were made, and subsampled for VII activity. The activation state of VII was judged by comparison of one-stage clotting assay to a coupled amidolytic assay using a synthetic substrate. In the presence of phospholipid (PL) and calcium (Ca), both IXa and Xa activated VII 25 fold; however, Xa was roughly 800 times more efficient than IXa. In the absence of PL, Xa was roughly 20 times more efficient than IXa, in Ca-containing solutions. Only slight activation of VII by either enzyme occurred in the absence of Ca. The addition of prothrombin (II) markedly slowed activation of VII by both Xa and IXa; however, this effect did not occur if fully-decarboxylated II was used. The addition of anti thrombin III and thrombin-modified factor VIII at physiologic concentrations did not change rates of VII activation by IXa or Xa.These results confirm the ability of IXa and Xa to activate factor VII at physiologic concentrations in purified systems. The higher relative efficiency of Xa over IXa under all conditions studied contrasts strikingly with observations in whole plasma systems where the VII activation measurable after clotting is greater in X-deficient than in IX-deficient plasma. The activation of VII by Xa and IXa may serve as an amplification loop in the generation of clotting by either “intrinsic” or “extrinsic” cascades.

DEFECTS OF VITAMIN K-DEPENDENT FACTORS IN CA(11)-STABILI ZED STRUCTURE

1987 ◽  
Author(s):  
S R Poort ◽  
C Krommenhoek-van Es ◽  
I K van der Linden ◽  
N H van Tilburg ◽  
R M Bertina
Keyword(s):  
Vitamin K ◽  
Genetic Variants ◽  
Protein C ◽  
Conformational Transition ◽  
Oral Anticoagulants ◽  
Indirect Evidence ◽  
Coagulation Factors ◽  
Factor Ix ◽  
Factor Vii ◽  
Factor Ii

Vitamin K-dependent (anti)coagulation factors (factor II, VII, IX, X protein C and S) undergo a conformational transition upon binding of Ca(II), which is a prerequisite for their normal function. Abnormalities in these properties occur during vitamin K deficiency or treatment with anti vitamin K drugs and in some genetic variants of coagulation factors. Immunological assays utilizing antibodies against the Ca(II)-stabilized structure are useful to detect such abnormalities.Starting from specific rabbit antisera antibody populations specific for the Ca(II)-dependent conformation of factor II, VII, IX, X and protein C and S were isolated using immuno-affinity procedures. Subsequently immunoradiometric assays specific for the Ca(II)-dependent (Ca(II)Ag) and Ca(II)-independent (NonCa(II)Ag) conformations of the different proteins were developed. These assays were used for the analysis of plasmas of patients stably treated with oral anticoagulants; Ca(II)Ag, NonCa(II)Ag and their ratio were measured as function of the intensity of the treatment (INR 2.4 to 4.8). The same parameters were measured in plasmas of patients with hereditary coagulation disorders. After treatment with oral anticoagulation with an antivitamin K drug reduced ratios of Ca(II)Ag/-NonCa(II)Ag were observed for factor II, VII, IX, protein C and protein S. However, the actual degree of reduction and its dependence on the intensity of treatment varied for the different vitamin K-dependent proteins. In general Ca(II)Ag levels correspond nicely with the procoagulant activity of the concerning proteins. These data provide indirect evidence for the existence of abnormal (non and/or subcarboxylated) forms of the vitamin K-dependent proteins during oral anticoagulant treatment.Genetic variants with a mutation in one of the sites involved in the formation of the Ca(II)-s tab i1ized structure could be detected for factor IX, factor VII and factor II. However, the extent of reduction of the ratio Ca(II)Ag/-NonCa(II)Ag differed considerably in those variants.

scholarly journals Activation of human factor VII by activated factors IX and X

Blood ◽  
1982 ◽  
Vol 60 (5) ◽  
pp. 1143-1150 ◽  
Author(s):  
DR Masys ◽  
SP Bajaj ◽  
SI Rapaport
Keyword(s):  
Human Factors ◽  
Factor Viii ◽  
Active Site ◽  
Human Factor ◽  
Antithrombin Iii ◽  
Factor Ix ◽  
Factor Vii ◽  
Activate Factor ◽  
Factor X ◽  
Activated Factor Vii

Factor VII clotting activity increases about five-fold when blood is clotted in glass. Prior studies suggested that this results from activation induced by activated factor IX (IXa). However, in purified systems containing phospholipid and calcium, activated factor X (Xa) is known to activate factor VII rapidly. Therefore, we studied activation of factor VII by IXa and X, in systems using purified human factors. Concentrations of IXa and Xa were calculated from total activated protein concentrations rather than from active site concentrations. In the presence of phospolipid and calcium, both IXa and Xa activated factor VII 25-fold; however, Xa was roughly 800 times more efficient than IXa. Without added phospholipid, activation of factor VII by both Xa and IXa was markedly slowed, and Xa was roughly 20 times more efficient than IXa. When both phospholipid and calcium were omitted, activation of factor VII by either enzyme was negligible. Adding normal prothrombin, but not decarboxylated prothrombin, substantially slowed activation of factor VII by both Xa and IXa. Adding thrombin-activated factor VIII and antithrombin-III did not change rates of factor VII activation by either enzyme. These results from purified systems do not provide an explanation for the prior data from plasma systems.

Intrauterine Subdural Hemorrhage Associated with Profound Deficiency of the Vitamin K Dependent Clotting Factors in an Infant Homozygous for a Common Polymorphism in the Vitamin K Epoxide Reductase Complex 1 (VKORC1) Promoter.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2152-2152
Author(s):  
Nadav Schwartz ◽  
Johannes Oldenburg ◽  
David Hart ◽  
Michael Nardi ◽  
Ori Langer Most ◽  
...  
Keyword(s):  
Vitamin K ◽  
Gestational Age ◽  
Subdural Hematoma ◽  
Factor Ix ◽  
Factor Vii ◽  
Dietary Vitamin ◽  
Subdural Hemorrhage ◽  
Factor X ◽  
Clotting Factors ◽  
Complete Sequencing

Abstract Hemorrhage in newborn infants who have not received vitamin K supplementation is a well recognized entity, but hemorrhage occurring prenatally due to deficiency of the vitamin K dependent factors is not. We report a subdural hemorrhage in a fetus at 29 weeks of gestation associated with very low levels of vitamin K dependent factors. The pregnancy was monitored by periodic ultrasound because of a previous near term stillbirth to this mother for which no etiology was identified. At 29 weeks a 4.6 × 7.7 × 8.8 cm left subdural hematoma was detected. There is no history of bleeding in this Hispanic family and no known consanguinity. His mother was not taking coumadin or any other medication, and her coagulation studies were normal. The baby was delivered by cesarean section, blood drawn for coagulation studies and 1mg Vitamin K given intramuscularly. The baby oozed from the injection and venipuncture sites. The hematocrit was 19% (mean for gestational age = 40.88) and packed red blood cells were given followed by fresh frozen plasma (10ml/kg). Platelets were 284,000/cmm. At six hours of life coagulation studies were greatly improved, the factor levels now being in the normal range for 29 weeks gestational age. Results at birth, 6 hours and 6 months are shown in the table. At 6 hours the baby no longer oozed from venipuncture sites. He received 1mg vitamin K daily for 3 days and no further supplementation thereafter other than that contained in infant formula. The subdural hematoma was drained on day 1 of life. Growth and development at 20 months are normal. Complete sequencing of the VKORC1 gene showed a homozygous functional promoter polymorphism: VKORC1:c.[1–1639&gt;A]+[1–1639&gt;A] (VKORC1*2/*2). This A allele is associated with 25% less VKORC1 expression and protein (50% less for homozygotes) compared to the G allele. Complete sequencing of the gamma-glutamyl carboxylase gene revealed no functional abnormalities. Individuals homozygous for this VKORC1 polymorphism have a relatively low capacity to regenerate reduced vitamin K and should require more vitamin K intake than others. They are known to require less warfarin. We hypothesize that insufficient vitamin K was available in utero to this fetus to compensate for the relatively low reductase level, and he became severely factor deficient. In the extra uterine environment sufficient dietary vitamin K was available to compensate for his relatively low reductase level. It is possible that the previous unexplained stillbirth was due to hemorrhage because of a similar factor deficiency. A reason for an intrauterine paucity of vitamin K has not been determined but must be rare as 17% of Europeans and a larger number of Chinese are homozygous VKORC1*2/*2, and intrauterine hemorrhage due to this cause is not reported. Birth 6 hours 6 months Values in parentheses are ELISA assays. Other assays are functional. nd = not done PT (sec) &gt;120 17.6 13.7 PTT (sec) 176 50.3 35.2 Fibrinogen (mg/dL) 194 196 287 % Factor II 1 39 96 % Factor V 81 nd 116 % Factor VII 3 61 99 % Factor IX 1 nd 108 % Factor X 2 (33) nd 107 % Protein C &lt;1 (18) 27 nd

Treatment of Hereditary Protein C Deficiency with Stanozolol

1987 ◽  
Vol 57 (01) ◽  
pp. 020-024 ◽  
Author(s):  
A W Broekmans ◽  
J Conard ◽  
R G van Weyenberg ◽  
M H Horellou ◽  
C Kluft ◽  
...  
Keyword(s):  
Plasma Protein ◽  
Protein C ◽  
Protein S ◽  
Fold Increase ◽  
Factor Ix ◽  
Factor Vii ◽  
Type I ◽  
Factor V ◽  
Factor X ◽  
Protein C Deficiency

SummaryFive type I protein C deficient male patients received 5 mg stanozolol b.i.d. during 4 weeks. After four weeks of treatment plasma protein C activity increased from 0.42 to 0.74 U/ml and protein C antigen from 0.49 to 0.75 U/ml. This approximately 1.6 fold increase in plasma protein C was accompanied by an increase in factor II antigen (1.5 fold), factor V activity (1.6 fold), factor X antigen (1.1 fold), antithrombin III antigen (1.3 fold) and heparin cofactor II antigen (1.5 fold), while the concentration of factor VII, factor VIII, and factor IX activity, and of protein S antigen remained unchanged. Prothrombin fragment F1+2, measured in two patients, increased 1.3 fold. In addition to its effect on procoagulant and anticoagulant factors stanozolol had profibrinolytic effects, reflected in an increase in tPA activity and in the concentration of plasminogen. These data indicate that in type I protein C deficient patients stanozolol increases the concentrations of both procoagulant and anticoagulant factors and favours fibrinolysis. The efficacy of stanozolol in preventing thrombotic disease in type I protein C deficient patients, however, remains to be established. During the four weeks of stanozolol treatment no thrombotic manifestations were observed in the protein C deficient patients.

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