Investigating the mechanism of mrp/plf gene expression by bFGF

Abstract

Introduction Materials and Methods Results Discussion Acknowledgments References CHARACTERIZATION OF THE MECHANISM OF mrp3 PROMOTER ACTIVATION AND THE DIFFERENTIAL RESPONSE OF THE mrp/plf PROMOTERS BY bFGF 51

FREBP - an anchorage dependent transcription factor

“…These are as follows: MMP family members; stromelysin-1 (mmp-3), gelatinase A (mmp-2), collagenase type 1, gelatinase B (92 kDa type Iv collagenase, mmp-9) and other proteases; cathepsinL, cathepsin B, tissue plasminogen activator. Furthermore the protease genes not regulated by bFGF like elastase, metalloelastase, trypsin, and chymotrypsin did not contain FRE or FRE-like sequences [313]. This was a significant finding because not only are mmp 's expressed in the same tissues as mrp/plf's but also the proteins expressed by these mmp genes are involved in similar physiological tissue remodeling events like wound healing.…”

“…But if cJun-cFos heterodimers are present instead of cJun-cJun homodimers then a negative response is elicited in response to glucocorticoids [312]. PKC's induce cFos and cJun and it was shown that inhibiting PKC's did not have any effect on the bFGF regulation of mrp3 [313]. These experiments suggested that AP-1 is not involved in regulating mrp3 in response to bFGF stimulation.…”

“…The results of the competition assay showed that an oligomer (-179 to -162bp) that contained the 3' 2/3 of the FRE oligonucleotide competed successfully over the oligomer (-191 to -174) containing the 5' 2/3 of the FRE oligonucleotide for the nuclear proteins. This outlines the region from the FRE that the nuclear proteins were binding [313].…”

“…To determine if the binding of proteins) to the FRE is regulated by bFGF, one and three tandem repeats were linked upstream of the minimal mrp3 promoter -81 to +65-CATbasic reporter gene and were stably transfected into Swiss 3T3 cells. The addition of three tandem copies of FRE upstream of a basal TK promoter resulted in activation in response to bFGF [313]. The apparent native molecular weight of this FRE-protein complex was determined by the method of Hendrick and Smith [318] in 3T3 cells.…”

“…Then the proteins) bound to FRE were covalently linked by UV cross-linking to FRE (-186 to -167 oligonucleotides of mrp3 promoter) and run on SDS-PAGE where 2-3 bands were detected. Proteins ranging from 32 to 37 kDa were identified after subtracting the MW of the oligonucleotide (~23-28 kDa) [313].…”