The human EBAG9 was previously identified as an estrogen responsive gene us
ing CpG-genomic binding site cloning (Watanate et al, (1998) Mel. Cell. Bio
l. 18: 442-449). Recently it was revealed that the EBAG9 is identical with
RCAS1 which is a cancer cell. surface antigen implicated in immune escape.
Here, we isolated and analyzed the 5'-flanking region of human EBAG9 gene.
We determined transcription initiation site, which has a homology with an i
nitiator element YYCAYYYY, and found that TATA motif was absent. Deletion a
nalysis of the 5'-flanking region using MCF-7 breast cancer cells indicated
that the sequences -86 to -36 containing the ERE had the basal level of pr
omoter activity and the upstream CC-rich region positively regulated the ac
tivity. EBAG9 pro meter luciferase reporters containing the ERE could respo
nd to estrogen, and electrophoretic mobility shift assay showed that ER alp
ha bound to the ERE. Moreover, fluorescent in situ hybridization analysis h
as shown that the human EBAG9 gene is located at chromosome 8q23 which is f
requently amplified in tumors. These findings suggest that the human EBAG9
might be involved in carcinogenesis as an estrogen responsive gene, (C) 200
0 Academic Press.