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ISSN
1672-9145
Acta Biochim Biophys Sin
2005, 37(5): 303–309
CN 31-1940/Q
Identification of a Novel Nucleus Protein Involved in the Regulation
of Urokinase in 95D Cells
Chang TONG, Li TAN, Ping LI, and Yun-Song ZHU*
Department of Molecular Genetics, Key Laboratory of Molecular Medicine
of Education Ministry,
Shanghai Medical College of Fudan University, Shanghai 200032, China
Abstract The urokinase-type plasminogen activator (uPA) plays an important role
in cellular invasion. By using the downstream part of a 74 bp DNA region called
the cooperation mediator (COM) of the uPA promoter as a bait sequence in
the yeast one-hybrid screen, a gene called PBK1 was previously cloned
from the cDNA library of the 95D lung cancer cell strain. In this study, the
intracellular distribution of PBK1 was studied by using the transient
transfection of pEGFP-C3-PBK1, and PBK1 was found to be localized in the
nucleus. Co-transfection of pEGFP-C3-PBK1 and the deletion mutants of the
pGL3-uPA promoter indicated that PBK1 can increase the uPA promoter
activity by about 25% and this effect is uPA enhancer-dependent. Western
blotting and Enzyme-linked immunoadsordent assay further confirmed that PBK1
can upregulate the expression of uPA. Our results suggest that PBK1 is
involved in the regulation of uPA expression, which might provide a new
clue to further understanding the regulation mechanism of uPA
expression.
Key words PBK1; urokinase-type
plasminogen activator (uPA)
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Received: November 29, 2004 Accepted: March 5, 2005
The work was supported by a grant from the National Natural Science
Foundation of China (No. 30170398)
*Corresponding
author: Tel, 86-21-54237278; E-mail, [email protected]