Generation of a conditional knockout allele for the Janus kinase 2 (Jak2) gene in mice

Authors

  • Andrea Krempler,

    1. Eppley Institute for Research in Cancer and Allied Diseases and the Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska
    Current affiliation:
    1. Department of Medical Biochemistry and Molecular Biology, University of the Saarland, Building 44, Homburg, 66424, Germany
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    • A. Krempler and Y. Qi contributed equally to this work.

  • Yongyue Qi,

    1. Eppley Institute for Research in Cancer and Allied Diseases and the Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska
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    • A. Krempler and Y. Qi contributed equally to this work.

  • Aleata A. Triplett,

    1. Eppley Institute for Research in Cancer and Allied Diseases and the Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska
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  • Jianqiong Zhu,

    1. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
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  • Hallgeir Rui,

    1. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC
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  • Kay-Uwe Wagner

    Corresponding author
    1. Eppley Institute for Research in Cancer and Allied Diseases and the Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska
    • Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 986805 Nebraska Medical Center, Rm. 8009, Omaha, NE 68198-6805
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Abstract

To study biologically relevant functions of the Janus kinase 2 (Jak2) in multiple cytokine and hormone receptor signal transduction pathways, we generated a conditional knockout (floxed) allele of this gene by placing loxP sites around the first coding exon of Jak2. Homozygous floxed animals developed normally and exhibited no phenotypic abnormalities. The conversion of the floxed allele into a null mutation was achieved by transmitting the targeted allele through the female germline of MMTV-Cre (line A) mice. Embryos that carry two Jak2 null alleles died around midgestation and exhibited impaired definitive erythropoiesis, which is a hallmark of Jak2 deficiency reported previously in conventional knockouts. This observation suggested that the Cre-mediated deletion of the first coding exon results in a true null mutation that is incapable of mediating signals through the erythropoietin receptor. Using mouse embryonic fibroblasts derived from Jak2 null embryos and their wildtype littermate controls, we demonstrated that Jak2-deficiency decouples growth hormone-receptor signaling from its downstream mediators, the signal transducer and activator of transcription (Stat) 5a and 5b. genesis 40:52–57, 2004. © 2004 Wiley-Liss, Inc.

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