title: Immunoglobulin knockout chickens via efficient homologous recombination in primordial germ cells.
abstract: Gene targeting by homologous recombination or by sequence-specific nucleases allows the precise modification of genomes and genes to elucidate their functions. Although gene targeting has been used extensively to modify the genomes of mammals, fish, and amphibians, a targeting technology has not been available for the avian genome. Many of the principles of humoral immunity were discovered in chickens, yet the lack of gene targeting technologies in birds has limited biomedical research using this species. Here we describe targeting the joining (J) gene segment of the chicken Ig heavy chain gene by homologous recombination in primordial germ cells to establish fully transgenic chickens carrying the knockout. In homozygous knockouts, Ig heavy chain production is eliminated, and no antibody response is elicited on immunization. Migration of B-lineage precursors into the bursa of Fabricius is unaffected, whereas development into mature B cells and migration from the bursa are blocked in the mutants. Other cell types in the immune system appear normal. Chickens lacking the peripheral B-cell population will provide a unique experimental model to study avian immune responses to infectious disease. More generally, gene targeting in avian primordial germ cells will foster advances in diverse fields of biomedical research such as virology, stem cells, and developmental biology, and provide unique approaches in biotechnology, particularly in the field of antibody discovery.
authors.affiliation: Research Division, Crystal Bioscience Inc., Emeryville, CA 94608.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Schusser
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Collarini
authors.forename: Henry
authors.initials: H
authors.lastname: Yi
authors.forename: Shelley Mettler
authors.initials: SM
authors.lastname: Izquierdo
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Fesler
authors.forename: Darlene
authors.initials: D
authors.lastname: Pedersen
authors.forename: Kirk C
authors.initials: KC
authors.lastname: Klasing
authors.forename: Bernd
authors.initials: B
authors.lastname: Kaspers
authors.forename: William D
authors.initials: WD
authors.lastname: Harriman
authors.forename: Marie-Cecile
authors.initials: MC
authors.lastname: van de Lavoir
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Etches
authors.forename: Philip A
authors.initials: PA
authors.lastname: Leighton
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D015139:Blotting, Southern; D002645:Chickens / Q000235:genetics* / Q000276:immunology; D019175:DNA Methylation; D017931:DNA Primers / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D055786:Gene Knockout Techniques / Q000379:methods*; D005818:Genetic Engineering / Q000379:methods*; D005838:Genotype; D005854:Germ Cells / Q000737:chemistry* / Q000378:metabolism; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007150:Immunohistochemistry
chemical_list: D017931:DNA Primers; D007143:Immunoglobulin Heavy Chains
keywords: B-cell development; avian immunology; genome editing