Transactivation of the urokinase-type plasminogen activator receptor gene through a novel promoter motif bound with an activator protein-2alpha-related factor.
The urokinase receptor overexpressed in invasive cancers promotes laminin degradation. The current study was undertaken to identify cis elements and trans-acting factors activating urokinase receptor expression through a footprinted (-148/-124) region of the promoter containing putative activator protein-2- and Sp1-binding motifs. Mobility shifting experiments using nuclear extract from a high urokinase receptor-expressing cell line (RKO) indicated that Sp1, Sp3, and a factor similar to, but distinct from, activator protein-2alpha bound to this region. Mutations preventing the binding of the activator protein 2alpha-related factor diminished urokinase receptor promoter activity. In RKO cells, the expression of a negative regulator of activator protein-2 function diminished urokinase receptor promoter activity, protein, and laminin degradation. Conversely, urokinase receptor promoter activity in low urokinase receptor-expressing GEO cells was increased by activator protein-2alphaA expression. Although using GEO nuclear extract, little activator protein-2alpha-related factor bound to the footprinted region, phorbol 12-myristate 13-acetate treatment, which induces urokinase receptor expression, increased complex formation. Mutations preventing the activator protein-2alpha-related factor and Sp1/Sp3 binding reduced urokinase receptor promoter stimulation by this agent. Thus, the constitutive and phorbol 12-myristate 13-acetate-inducible expression of the urokinase receptor is mediated partly through trans-activation of the promoter via a sequence (-152/-135) bound with an activator protein-2alpha-related factor.
Allgayer
H
H
Department of Cancer Biology, M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
Wang
H
H
Wang
Y
Y
Heiss
M M
MM
Bauer
R
R
Nyormoi
O
O
Boyd
D
D
D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D018983:DNA Footprinting; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015536:Down-Regulation; D006868:Hydrolysis; D007797:Laminin / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000235:genetics*; D055293:Receptors, Urokinase Plasminogen Activator; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation