Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10905534 | Experimental Cell Research | 2005 | 12 Pages |
Abstract
The MUC1 mucin is a large membrane-tethered glycoprotein that shows differential expression in many adenocarcinomas, where it contributes to their invasive and metastatic properties. We previously identified DNase I hypersensitive sites at â750 and â250 bp in the human MUC1 gene promoter and showed concordance between the â250 site and MUC1 mRNA levels in vivo. Transient expression assays using promoter constructs, in which the core DHS was deleted, to drive reporter gene expression revealed in vivo evidence for their activity. DNase I footprinting using nuclear extracts from HPAF human pancreatic carcinoma cells and MCF7 breast carcinoma cells identified three protein-binding elements in these regions (â250FP1, FP2 and â750FP). Electrophoretic mobility shift assays detected several complexes between HPAF nuclear proteins and labeled FP DNA probes. Southwestern blots and UV cross-linking experiments identified myeloid zinc finger-1 (MZF-1) as a candidate transcription factor among proteins binding to the â250FP1 and FP2 sequences. Another candidate that was identified by screening an HPAF cDNA expression library with the â250FP1 probe is DNA binding protein A (DbpA). Exogenous DbpA expression in COS-7 cells was accompanied by upregulation of MUC1 promoter activity via the â250 DHS, suggesting that DbpA binding to the â250 DHS can influence human MUC1 gene expression.
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Authors
Toshiyuki Shiraga, John P. Winpenny, Emma J. Carter, Victoria A. McCarthy, Michael A. Hollingsworth, Ann Harris,