Attenuation of plasminogen activator inhibitor type-1 promoter activity in serum-stimulated renal epithelial cells by a distal 5' flanking region.
Urokinase plasminogen activator (u-PA) and its fast acting type-1 inhibitor (PAI-1) localize to cellular focal adhesive structures and the adjoining proximal undersurface region, respectively (Kutz et al., J. Cell. Physiol. 176:8-18, 1997). PAI-1 may function in this locale to modulate pericellular proteolytic activity, cell-to-substrate adhesion, or matrix-dependent motility. While PAI-1 synthesis is regulated in an immediate-early response manner in growth "activated" renal cells coincident with cytoskeletal restructuring, adhesive influences both repress the amplitude and prolong the time course of serum-induced PAI-1 transcription (Ryan et al., Biochem. J. 314:1041-1046, 1996). To identify potential adhesion-responsive elements within the PAI-1 gene that function in this complex mode of expression control, reporter constructs containing defined directionally deleted PAI-1 5' genomic fragments cloned upstream of a CAT gene were employed in transient transfection assays. A 483-bp distal PAI-1 flanking segment (corresponding to nucleotides -2395 to -1912) conferred significant adhesion-dependent attenuation on serum-induced PAI-1 transcription. This 483-bp distal PAI-1 segment functioned as a repressor of reporter (CAT) activity under both adhesive and suspension culture conditions, however, when ligated upstream of either an SV40 promoter/enhancer or a minimal PAI-1 promoter. These data suggest that repressor elements located between -2395 and -1912 bp interact with more proximal adhesion-dependent regulatory elements to affect PAI-1 expression attenuation during serum stimulation of adherent renal epithelial cells.
Slack
J K
JK
Cell and Molecular Biology Program, Albany Medical College, Albany, New York 12208, USA.
Higgins
P J
PJ
D000818:Animals; D002448:Cell Adhesion; D002460:Cell Line; D003470:Culture Media; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology; D005786:Gene Expression Regulation; D007668:Kidney / Q000166:cytology; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics*; D011401:Promoter Regions, Genetic; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid; D012710:Serum Albumin, Bovine
D003470:Culture Media; D017395:Plasminogen Activator Inhibitor 1; D012710:Serum Albumin, Bovine