title: A novel transgenic chimaeric mouse system for the rapid functional evaluation of genes encoding secreted proteins.
abstract: A major challenge of the post-genomic era is the functional characterization of anonymous open reading frames (ORFs) identified by the Human Genome Project. In this context, there is a strong requirement for the development of technologies that enhance our ability to analyze gene functions at the level of the whole organism. Here, we describe a rapid and efficient procedure to generate transgenic chimaeric mice that continuously secrete a foreign protein into the systemic circulation. The transgene units were inserted into the genomic site adjacent to the endogenous immunoglobulin (Ig) kappa locus by homologous recombination, using a modified mouse embryonic stem (ES) cell line that exhibits a high frequency of homologous recombination at the Igkappa region. The resultant ES clones were injected into embryos derived from a B-cell-deficient host strain, thus producing chimaerism-independent, B-cell-specific transgene expression. This feature of the system eliminates the time-consuming breeding typically implemented in standard transgenic strategies and allows for evaluating the effect of ectopic transgene expression directly in the resulting chimaeric mice. To demonstrate the utility of this system we showed high-level protein expression in the sera and severe phenotypes in human EPO (hEPO) and murine thrombopoietin (mTPO) transgenic chimaeras.
authors.affiliation: Pharmaceutical Research Laboratory, Pharmaceutical Division, Kirin Brewery Co. Ltd. 3 Miyahara-cho, Takasaki-shi, Gunma 370-1295, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kakitani
authors.forename: Takeshi
authors.initials: T
authors.lastname: Oshima
authors.forename: Kaori
authors.initials: K
authors.lastname: Horikoshi
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Yoshitome
authors.forename: Akiko
authors.initials: A
authors.lastname: Ueda
authors.forename: Miwa
authors.initials: M
authors.lastname: Kajikawa
authors.forename: Yumi
authors.initials: Y
authors.lastname: Iba
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Ozone
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ijima
authors.forename: Tohko
authors.initials: T
authors.lastname: Yoshino
authors.forename: Mikiko
authors.initials: M
authors.lastname: Itoh
authors.forename: Sachiko
authors.initials: S
authors.lastname: Seki
authors.forename: Ayako
authors.initials: A
authors.lastname: Aoki
authors.forename: Toshie
authors.initials: T
authors.lastname: Ishihara
authors.forename: Michiyo
authors.initials: M
authors.lastname: Shionoya
authors.forename: Utako
authors.initials: U
authors.lastname: Makino
authors.forename: Rina
authors.initials: R
authors.lastname: Kitada
authors.forename: Atsuko
authors.initials: A
authors.lastname: Ohguma
authors.forename: Takami
authors.initials: T
authors.lastname: Ohta
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Hiroe
authors.initials: H
authors.lastname: Kudoh
authors.forename: Kazunori
authors.initials: K
authors.lastname: Hanaoka
authors.forename: Kazunori
authors.initials: K
authors.lastname: Sibuya
authors.forename: Isao
authors.initials: I
authors.lastname: Ishida
authors.forename: Minoru
authors.initials: M
authors.lastname: Kakeda
authors.forename: Mikio
authors.initials: M
authors.lastname: Yagi
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoneya
authors.forename: Kazuma
authors.initials: K
authors.lastname: Tomizuka
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism; D002460:Cell Line; D002678:Chimera; D002999:Clone Cells; D004622:Embryo, Mammalian / Q000166:cytology; D004921:Erythropoietin / Q000097:blood / Q000235:genetics; D018390:Gene Targeting; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*; D011995:Recombination, Genetic; D013234:Stem Cells / Q000166:cytology; D013926:Thrombopoietin / Q000097:blood / Q000235:genetics
chemical_list: D011506:Proteins; D004921:Erythropoietin; D013926:Thrombopoietin