A MULTICOPY c-myc TRANSGENE AS A NUCLEAR LABEL: OVERGROWTH OF Myctg50CELLS IN ALLOPHENIC MICE

Authors

  • MARTIN AUGUSTIN,

    1. Developmental Biology and Molecular Pathology, University of Bielefeld, D-33501, Bielefeld, Germany
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    • Biofrontera Pharmaceuticals GmbH, Hemmelrather Weg 201, D-51377 Leverkusen.

  • NORMAN KLOPP,

    1. Developmental Biology and Molecular Pathology, University of Bielefeld, D-33501, Bielefeld, Germany
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    • Institute for Mammalian Genetics, GSF, D-85758 Oberschleissheim.

  • KAI EWALD,

    1. Developmental Biology and Molecular Pathology, University of Bielefeld, D-33501, Bielefeld, Germany
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  • HARALD JOCKUSCH

    Corresponding author
    1. Developmental Biology and Molecular Pathology, University of Bielefeld, D-33501, Bielefeld, Germany
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Developmental Biology and Molecular Pathology, University of Bielefeld, D-33501 Bielefeld, Germany; E-mail: h.jockusch@biologie.uni-bielefeld.de

Abstract

To trace cell lineages and the origin and fate of cells in transplantation and embryo chimeras, a DNA/DNA in situ hybridization cell labelling system was developed, based on a 50-copy murine c-myc transgene on mouse chromosome 8. Elevated levels of cMyc mRNA were found in Myc*tg50 (Myctg50/0 and Myctg50/Myctg50) transgenic tissues, but adult transgenic NMRI mice were anatomically and histologically indistinguishable from control NMRI mice and did not develop tumours on a wild-type or nude (nu / nu) background. The hybridization label detected transgenic nuclei with an efficiency of ∼80%. In muscle grafts, this transgene label was successfully applied to trace donor cells in a labelled host and to study the invasion of a graft by host cells. When the cMyc hybridization was used in allophenic mice of the control|acNMRI-Myctg50/? (nu /+ or +/+) type, an up to a three-fold excess of MYC*tg50 positive over control nuclei was found in all organs examined (ventricle, skeletal muscle, liver, small intestine). This overgrowth of MYC*tg50 cells is probably due to transgene expression. Four out of seven (C57BL/6×BALB/c) or (C57BL/6×NMRI)|acMYC*tg50 allophenic mice displayed anatomical abnormalities, e.g. an enlarged thymus and a tumour in the groin region. As these abnormalities were only observed in allophenic mice, they might be due to the imbalance of growth potential between MYC*tg50 transgenic and normal cells in the same individual.

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