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This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Peyvandi, F. Articles by Bauer, K. A. Search for Related Content PubMed PubMed Citation Articles by Peyvandi, F. Articles by Bauer, K. A. Related Collections Hemostasis, Thrombosis, and Vascular Biology Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  Blood, 15 February 2001, Vol. 97, No. 4, pp. 960-965 HEMOSTASIS, THROMBOSIS, AND VASCULAR BIOLOGY Abnormal secretion and function of recombinant human factor VII as the result of modification to a calcium binding site caused by a 15-base pair insertion in the F7 gene Flora Peyvandi, Josephine A. Carew, David J. Perry, Mathilde Hunault, Uma Khanduri, Stephen J. Perkins, Pier M. Mannucci, and Kenneth A. Bauer From the Hematology Section, Department of Medicine, VA Boston Healthcare System, Harvard Medical School, Boston, MA; the Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, IRCCS Maggiore Hospital, and the University of Milan, Italy; the Hemophilia Centre and Hemostasis Unit, Department of Hematology, and the Department of Biochemistry and Molecular Biology, The Royal Free and University College Medical School, London, England; and the Department of Hematology, College of Medicine, Sultan Qaboos University Al-Khod, Sultanate of Oman. A case of a novel mutation in the F7 gene that results in factor VII coagulant activity (VII:c) of less than 1% and VII antigen (VII:Ag) levels of 10% is presented. DNA analysis revealed a homozygous 15-base pair (bp) in-frame insertion-type mutation at nucleotide 10554. This insertion consisted of a duplication of residues leucine (L)213 to aspartic acid (D)217 (leucine, serine, glutamic acid, histidine, and aspartic acid), probably arising by slipped mispairing between 2 copies of a direct repeat (GCGAGCACGAC) separated by 4 bp. Molecular graphic analyses showed that the insertion is located at the surface of the catalytic domain in an exposed loop stabilized by extensive salt-bridge and hydrogen bond formation at which the calcium binding site is located. The mutation probably interferes with protein folding during VII biosynthesis and/or diminishes functional activity through the loss of calcium binding. In vitro expression studies demonstrated that the levels of VII:Ag in lysates of cells transfected with wild type VII (VIIWT) were equivalent to those with mutant type VII (VIIMT), but the level of secreted VIIMT was 5% to 10% that of VIIWT. Pulse chase studies demonstrated that VIIMT did not accumulate intracellularly, and studies with inhibitors of protein degradation showed that recombinant VIIMT was partially degraded in the pre-Golgi compartment. Accordingly, only small amounts of VIIMT with undetectable procoagulant activity were secreted into conditioned media. These results demonstrate that a combination of secretion and functional defects is the mechanism whereby this insertion causes VII deficiency. © 2001 by The American Society of Hematology.   CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: P. M. Mannucci, S. Duga, and F. Peyvandi Recessively inherited coagulation disorders Blood, September 1, 2004; 104(5): 1243 - 1252. [Abstract] [Full Text] [PDF]

	Copyright © 2001 by American Society of Hematology         Online ISSN: 1528-0020