Transgenic mice demonstrate novel promoter regions for tissue-specific expression of the urokinase receptor gene.
The urokinase-type plasminogen activator receptor (u-PAR) contributes to cell migration and proteolysis in normal and cancerous tissues. Currently, there are no reports on the regulatory regions directing tissue-specific expression. Consequently, we undertook a study to identify novel promoter regions required for expression of this gene in transgenic mice bearing a LacZ reporter regulated by varying amounts (0.4, 1.5, and 8.5 kb) of upstream sequence. The 0.4-kb u-PAR upstream sequence directed weak and strong LacZ expression in the placenta and epididymis, respectively, both of which are tissues that express endogenous u-PAR. Conversely, transgene expression in the apical cells of the colon positive for endogenous u-PAR protein required 1.5 kb of upstream sequence for optimal expression. Furthermore, chromatin accessibility assays coupled with real-time polymerase chain reaction suggested a putative regulatory region spanning -1295/-1192 driving u-PAR expression in colonic cells. Interestingly, placental transgene expression was augmented with the 8.5-kb upstream fragment compared with the shorter 1.5-kb fragment indicating contributing element(s) between -1.5 and -8.5 kb. Thus, while 0.4 kb of upstream sequence directs u-PAR expression in the epididymis, sequences located between -0.4 and -1.5 kb and between -1.5 and -8.5 kb are required for optimal tissue-specific expression in the colon and the placenta, respectively.
Wang
Heng
H
Department of Cancer Biology, MD Anderson Cancer Center, Houston, Texas 77030, USA.
Hicks
John
J
Khanbolooki
Parham
P
Kim
Sun-Jin
SJ
Yan
Chunhong
C
Wang
Yao
Y
Boyd
Douglas
D
D000818:Animals; D002843:Chromatin / Q000378:metabolism; D003106:Colon / Q000166:cytology / Q000378:metabolism; D004822:Epididymis / Q000166:cytology / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D010920:Placenta / Q000166:cytology / Q000378:metabolism; D010960:Plasminogen Activators / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D055293:Receptors, Urokinase Plasminogen Activator; D014018:Tissue Distribution
D002843:Chromatin; C524899:Plaur protein, mouse; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D010960:Plasminogen Activators