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A novel homologous recombination system to study 92 kDa type IV collagenase transcription demonstrates that the NFκB motif drives the transition from a repressed to an activated state of gene expression
Author(s) -
Yan Chunhong,
Wang Heng,
Aggarwal Bharat B.,
Boyd Douglas D.
Publication year - 2004
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.03-0960fje
Subject(s) - plasmid , promoter , biology , gene , transfection , transcription (linguistics) , luciferase , regulation of gene expression , microbiology and biotechnology , gene expression , reporter gene , chromatin , homologous recombination , transcription factor , genetics , linguistics , philosophy
The 92‐kDa type IV collagenase (MMP‐9) contributes to tissue remodeling in both physiology and pathology. Previous studies on the transcriptional regulation of this gene have used transiently transfected promoter–reporter constructs. However, this approach suffers from several limitations including (a) multiple copies of the plasmid and (b) the plasmid is not genomically integrated and consequently poorly chromatinized. We developed a novel system for studying MMP‐9 transcription in which a single copy of a MMP‐9 promoter–luciferase construct(s) is integrated at an identical genomic locus in HT1080 cells by homologous recombination. We report that the activity of a genomic‐integrated 2.2 kb MMP‐9 promoter sequence mirrors expression of the endogenous MMP‐9 gene in response to both physiological and pharmacological (curcumin) cues. Further, when constrained into chromatin, the integrated NF‐κB‐mutated MMP‐9 promoter is repressed by PMA, a situation not apparent using nonintegrated plasmids. Thus, we have developed a novel method for studying MMP‐9 expression that overcomes some of the limitations associated with transient transfection approaches and which may be of utility in screening for agents that repress the expression of this gene.