The mouse BP-1 gene: Structure, chromosomal localization, and regulation of expression by type I interferons and interleukin-7
- Univ. of Alabama, Birmingham, AL (United States); and others
The BP-1/6C3 antigen is a homodimeric, phosphorylated type II membrane integral glycoprotein expressed on immature B-lineage cells, bone marrow stromal cells, thymic cortical epithelial cells, endothelial cells, thymic cortical epithelial cells, endothelial cells, thymic cortical epithelial cells, endothelial cells, enterocytes, and renal proximal tubular cells. Biochemical and molecular analysis identified BP-1 as glutamyl aminopeptidase, an ectoenzyme that catalyzes the hydrolysis of acidic amino acid residues from the amino termini of regulatory peptides. We have isolated genomic clones that encode the BP-1 gene (gene symbol Enpep). The gene spans more than 110 kb and contains 20 exons, it is composed of small exons ranging from 56 to 171 bp that are separated by introns ranging from less than 100 bp to approximately 10 kb. The zinc binding motif HEXXH and the glutamic acid residue 19 amino acids downstream, which also binds zinc, are encoded in exons 5 and 6. Primer extension analysis revealed a common major transcriptional start site in a pre-B cell line, in a bone marrow stromal cell line, and in kidney cells. An interferon responsive element also located in the promoter region appeared to be functional, since type I interferons (IFN-{alpha}/IFN-{beta}) upregulated BP-1 expression in pre-B cell lines. The BP-1/Enpep gene was localized to a distal region of mouse chromosome 3 in a region homologous to human chromosome 4q25. Interestingly, while interleukin-7 (IL-7) induced both cell growth and increased BP-1 expression, IFN-{alpha}/IFN-{beta} upregulated BP-1 expression but inhibited IL-7-induced proliferation. This finding indicates that the upregulated BP-1 expression can be disassociated from the cell growth signal. 48 refs., 7 figs., 1 tab.
- OSTI ID:
- 465945
- Journal Information:
- Genomics, Vol. 33, Issue 2; Other Information: PBD: 15 Apr 1996
- Country of Publication:
- United States
- Language:
- English
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