title: Phenotypic and functional characterization of a mouse model of targeted Pig-a deletion in hematopoietic cells.
abstract: BACKGROUND
  Somatic mutation in the X-linked phosphatidylinositol glycan class A gene (PIG-A) causes glycosyl phosphatidylinositol anchor deficiency in human patients with paroxysmal nocturnal hemoglobinuria.
  
  
  METHODS
  We produced an animal model of paroxysmal nocturnal hemoglobinuria by conditional Pig-a gene inactivation (Pig-a(-/-)) in hematopoietic cells; mice carrying two lox sites flanking exon 6 of the Pig-a gene were bred with mice carrying the transgene Cre-recombinase under the human c-fes promoter. We characterized the phenotypic and functional properties of glycosyl phosphatidylinositol-deficient and glycosyl phosphatidylinositol-normal hematopoietic cells from these Pig-a(-/-) mice using gene expression microarray, flow cytometry, bone marrow transplantation, spectratyping, and immunoblotting.
  
  
  RESULTS
  In comparison to glycosyl phosphatidylinositol-normal bone marrow cells, glycosyl phosphatidylinositol-deficient bone marrow cells from the same Pig-a(-/-) animals showed up-regulation of the expression of immune function genes and contained a significantly higher proportion of CD8 T cells. Both characteristics were maintained when glycosyl phosphatidylinositol-deficient cells were transplanted into lethally-irradiated recipients. Glycosyl phosphatidylinositol-deficient T cells were inactive, showed pronounced Vbeta5.1/5.2 skewing, had fewer gamma-interferon-producing cells after lectin stimulation, and contained fewer CD4(+)CD25(+)FoxP3(+) regulatory T cells. However, the levels of T-cell receptor signaling proteins from glycosyl phosphatidylinositol-deficient cells were normal relative to glycosyl phosphatidylinositol-normal cells from wild type animals, and cells were capable of inducing target cell apoptosis in vitro.
  
  
  CONCLUSIONS
  Deletion of the Pig-a gene in hematopoietic cells does not cause frank marrow failure but leads to the appearance of clonally-restricted, inactive yet functionally competent CD8 T cells.
authors.affiliation: Hematology Branch, NHLBI, National Institutes of Health, Bethesda, MD 20892-1202 USA. viscontev@mail.nih.gov
authors.forename: Valeria
authors.initials: V
authors.lastname: Visconte
authors.forename: Nalini
authors.initials: N
authors.lastname: Raghavachari
authors.forename: Delong
authors.initials: D
authors.lastname: Liu
authors.forename: Keyvan
authors.initials: K
authors.lastname: Keyvanfar
authors.forename: Marie J
authors.initials: MJ
authors.lastname: Desierto
authors.forename: Jichun
authors.initials: J
authors.lastname: Chen
authors.forename: Neal S
authors.initials: NS
authors.lastname: Young
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D004195:Disease Models, Animal; D005260:Female; D017353:Gene Deletion; D006457:Hemoglobinuria, Paroxysmal / Q000235:genetics*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D010641:Phenotype; D015854:Up-Regulation
chemical_list: D008565:Membrane Proteins; C080086:phosphatidylinositol glycan-class A protein
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