Mice Transgenic for the Human CGM6 Gene Express Its Product,
the Granulocyte Marker CD66b, Exclusively in Granulocytes
Anne-Marie Eades-Perner,
John Thompson,
Herman van der Putten, and
Wolfgang Zimmermann
From the Institute of Immunobiology, University of Freiburg,
Freiburg, Germany; and Novartis, Basel, Switzerland.
The nonspecific cross-reacting antigen-95 (NCA-95/CD66b), is a
member of the human carcinoembryonic antigen (CEA) family encoded by
the CGM6 gene that is exclusively expressed in neutrophils and
eosinophils. No murine counterpart is known to exist. We have analyzed
a cosmid containing the complete CGM6 gene. The coding sequence
is contained within six exons spanning a 16.5 kb region. The main
transcriptional start site was mapped to a tight cluster between
nucleotides -95 and -101 relative to the translational start site. As
with other members of the CEA gene family, no typical TATA or CAAT-box
sequences were found in the CGM6 gene. Transgenic mice were
established with the cosmid insert. CD66b expression is first seen in
the fetal liver on day 12.5 of mouse embryonic development, and it
first appears in the bone marrow at day 17.5. Northern blot analysis
showed that CD66b transcripts are confined to the bone marrow of adult
mice, whereas immunohistochemistry also showed CD66b-positive
granulocytes in the spleen, thymus, and lungs. FACScan analyses of bone
marrow and spleen cells showed CD66b expression to be exclusive to
granulocytes. Thus, all the elements necessary for regulating
granulocyte-specific expression are present within this cosmid clone.
These mice could provide a model for transplantation and for
inflammation studies using CD66b as a granulocyte-specific marker.
Blood, Vol. 91 No. 2 (January 15), 1998:
pp. 663-672
© 1998 by The American Society of Hematology.
