THE CEA10 GENE ENCODES A SECRETED MEMBER OF THE MURINE CARCINOEMBRYONIC ANTIGEN FAMILY AND IS EXPRESSED IN THE PLACENTA, GASTROINTESTINAL-TRACT AND BONE-MARROW
U. Keck et al., THE CEA10 GENE ENCODES A SECRETED MEMBER OF THE MURINE CARCINOEMBRYONIC ANTIGEN FAMILY AND IS EXPRESSED IN THE PLACENTA, GASTROINTESTINAL-TRACT AND BONE-MARROW, European journal of biochemistry, 229(2), 1995, pp. 455-464
Although members of the carcinoembryonic antigen (CEA) family have bee
n shown to convey cell adhesion in vitro, their location in some tissu
es contradicts such a function. As a basis for investigating their in
vivo functions, we are characterizing the mouse CEA family. This paper
describes the structure and expression of a new murine family member,
cea10. Two full-length cDNA clones were isolated from a mouse colon l
ibrary, whose deduced protein sequence comprises two immunoglobulin va
riable-like N-domains, directly followed by a short C-terminal domain
indicating that this molecule is secreted. Although this domain organi
zation suggests a closer relationship to the murine pregnancy-specific
glycoproteins (PSG), which form a subgroup within the CEA family, seq
uence comparisons place Cea10 within the CEA subgroup. Overlapping cos
mid clones containing the complete cea10 locus were mapped and the exo
ns determined. No A2-like exon, characteristic for all other members o
f the murine CEA family, could be found. Sequences of the promoter and
the first exon showed remarkably high similarity to the corresponding
regions of bgp1 and bgp2, two other members of the murine CEA subgrou
p. Consensus sequences for two transcription factors (USF and an AP-2-
like factor) that bind to the human BGP gene promoter were also presen
t in the cea10 promoter and possibly convey expression of these genes
in epithelial cells. RNase protection assays revealed transcriptional
activity of cea10 in the colon and early placenta (10.5-12.5-day embry
os) and to a lower extent in the small intestine, cecum, stomach, sali
vary glands and bone marrow. As some other CEA family members are dere
gulated in tumors, we quantified the expression levels of Cea10 transc
ripts in colonic mucosa and in adenomatous polyps of Min/+ mice. No di
fferences in the steady-state levels of Cea10 mRNA could be found, sug
gesting that the Cea10 protein does not play a role in early tumor dev
elopment. Taken together, Cea10 combines characteristic features of bo
th CEA and PSG subgroup members in its structure and expression patter
n.