title: The X-linked immunodeficiency defect in the mouse is corrected by expression of human Bruton's tyrosine kinase from a yeast artificial chromosome transgene.
abstract: Mutations in the gene for Bruton's tyrosine kinase result in the B cell differentiation defects X-linked agammaglobulinemia in man and X-linked immunodeficiency in mice. Here we describe the generation of two yeast artificial chromosome (YAC)-transgenic mouse strains in which high-level expression of human Btk is provided by endogenous regulatory cis-acting elements that are present on a 340-kb transgene, Yc340-hBtk. The expression pattern of the transgenic human Btk was found to parallel that of the endogenous murine gene. When the Yc340-hBtk-transgenic mice were mated onto a Btk-deficient background, the xid B cell defects were fully corrected: conventional and CD5+ B-1 B cells were present in normal numbers, serum IgM and IgG3 levels as well as responses to T cell-independent type II antigens were in the normal ranges. In vivo competition experiments in Btk+/- female mice demonstrated that in the conventional B cell population the Yc340-hBtk transgene could fully compensate the absence of expression of endogenous murine Btk. We conclude that in the YAC-transgenic mice Btk is appropriately expressed in the context of native regulatory sequences.
authors.affiliation: Department of Cell Biology and Genetics, Faculty of Medicine, Erasmus University Rotterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Maas
authors.forename: G M
authors.initials: GM
authors.lastname: Dingjan
authors.forename: H F
authors.initials: HF
authors.lastname: Savelkoul
authors.forename: C
authors.initials: C
authors.lastname: Kinnon
authors.forename: F
authors.initials: F
authors.lastname: Grosveld
authors.forename: R W
authors.initials: RW
authors.lastname: Hendriks
mesh_terms: D000077329:Agammaglobulinaemia Tyrosine Kinase; D000818:Animals; D000917:Antibody Formation; D000955:Antigens, T-Independent / Q000276:immunology; D001402:B-Lymphocytes / Q000502:physiology*; D018244:Chromosomes, Artificial, Yeast; D005260:Female; D005816:Genetic Complementation Test; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000201:enzymology* / Q000235:genetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*
chemical_list: D000955:Antigens, T-Independent; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human; C000625951:Btk protein, mouse