MZF-1 and DbpA interact with DNase I hypersensitive sites that correlate with expression of the human MUC1 mucin gene.
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 -750 and -250 bp in the human MUC1 gene promoter and showed concordance between the -250 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 (-250FP1, FP2 and -750FP). 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 -250FP1 and FP2 sequences. Another candidate that was identified by screening an HPAF cDNA expression library with the -250FP1 probe is DNA binding protein A (DbpA). Exogenous DbpA expression in COS-7 cells was accompanied by upregulation of MUC1 promoter activity via the -250 DHS, suggesting that DbpA binding to the -250 DHS can influence human MUC1 gene expression.
Shiraga
Toshiyuki
T
Paediatric Molecular Genetics, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK.
Winpenny
John P
JP
Carter
Emma J
EJ
McCarthy
Victoria A
VA
Hollingsworth
Michael A
MA
Harris
Ann
A
D000818:Animals; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D019556:COS Cells; D018938:Caco-2 Cells; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003850:Deoxyribonuclease I / Q000378:metabolism*; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D051741:Kruppel-Like Transcription Factors; D008969:Molecular Sequence Data; D018396:Mucin-1 / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism*
D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; D051741:Kruppel-Like Transcription Factors; C085969:MZF1 protein, human; D018396:Mucin-1; D014157:Transcription Factors; C094867:YBX3 protein, human; D003850:Deoxyribonuclease I