title: Structure and chromosomal localization of the GPI-anchor synthesis gene PIGF and its pseudogene psi PIGF.
abstract: Posttranslational modification by the GPI glycolipid anchor is essential for the surface expression of many membrane proteins. Defect of GPI biosynthesis due to somatic mutation in the hematopoietic stem cell is the basis for an acquired genetic disease, paroxysmal nocturnal hemoglobinuria (PNH). Previously, an X-linked gene PIGA (phosphatidylinositol glycan class A), which participates in the first step of the biosynthesis, was shown to be mutated in abnormal cells from all 60 patients with PNH. The cDNA of another GPI synthesis gene PIGF was previously cloned, but it is not involved in pathogenesis of PNH. In the present study, we have analyzed PIGF genomic clones. The PIGF gene contained six exons spanning about 40 kb and was located to the short arm of chromosome 2 at 2p16-p21. The frequency of mutations on both alleles of PIGF should be much lower than that of mutation in the X-linked PIGA, accounting for a lack of involvement of PIGF in PNH. We also identified the processed pseudogene of PIGF (psi PIGF) and mapped it to 5q35.
authors.affiliation: Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ohishi
authors.forename: N
authors.initials: N
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Fujita
authors.forename: J
authors.initials: J
authors.lastname: Takeda
authors.forename: T
authors.initials: T
authors.lastname: Kinoshita
mesh_terms: D001483:Base Sequence; D002874:Chromosome Mapping; D002889:Chromosomes, Human, Pair 2; D002895:Chromosomes, Human, Pair 5; D005091:Exons; D005796:Genes; D017261:Glycosylphosphatidylinositols / Q000096:biosynthesis / Q000235:genetics*; D006457:Hemoglobinuria, Paroxysmal / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D011506:Proteins / Q000235:genetics*; D011544:Pseudogenes; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014960:X Chromosome
chemical_list: D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; C098069:PIGF protein, human; D011506:Proteins