title: Age-specific regulation of clotting factor IX gene expression in normal and transgenic mice.
abstract: Factor IX (FIX), a circulating serine protease that serves as an essential component of the blood coagulation pathway, has been shown to increase with age in humans. We show here that murine FIX mRNA and activity levels also increase with age. Furthermore, one form of hemophilia B, hemophilia B Leyden, which is caused by mutations within the promoter region of the FIX gene, has a distinct age-dependent phenotype. To determine the source of the age-related increases in FIX gene expression, we have analyzed the regulation of the normal FIX gene promoter and FIX Leyden gene promoter with the +13 mutation during aging by generating transgenic mice that contain the -189 to +21 bp promoter segment ligated to a chloramphenicol acetyltransferase reporter gene. We have established that the normal FIX promoter and the Leyden promoter transgenes are expressed in a tissue-specific manner in vivo. The normal FIX promoter transgene does not show any differences in the pattern of expression with age or sex of the organism, whereas the Leyden promoter transgene showed age-dependent male-specific expression. This is the first demonstration of the FIX Leyden phenotype in a transgenic mouse model.
authors.affiliation: Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio 78284-7762, USA.
authors.forename: E J
authors.initials: EJ
authors.lastname: Boland
authors.forename: Y C
authors.initials: YC
authors.lastname: Liu
authors.forename: C A
authors.initials: CA
authors.lastname: Walter
authors.forename: D C
authors.initials: DC
authors.lastname: Herbert
authors.forename: F J
authors.initials: FJ
authors.lastname: Weaker
authors.forename: M W
authors.initials: MW
authors.lastname: Odom
authors.forename: P
authors.initials: P
authors.lastname: Jagadeeswaran
mesh_terms: D000367:Age Factors; D000818:Animals; D001483:Base Sequence; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000235:genetics; D005164:Factor IX / Q000096:biosynthesis / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D005813:Genes, Synthetic; D002836:Hemophilia B / Q000235:genetics* / Q000503:physiopathology; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011627:Puberty; D012333:RNA, Messenger / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012741:Sexual Maturation
chemical_list: D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C064567:factor IX Leyden; D005164:Factor IX; D015500:Chloramphenicol O-Acetyltransferase