Weakening of the repressive YY-1 site on the thrombospondin-1 promoter via c-Jun/YY-1 interaction.
- Author:
Jung Hoon KANG
1
;
Seo Yoon CHANG
;
Dong Hoon YEOM
;
Soo A KIM
;
Soo Hoon UM
;
Kyong Ja HONG
Author Information
1. Department of Biochemistry College of Medicine, The Catholic University of Korea 505 Banpo-dong, Socho-gu Seoul 137-701, Korea. kjhong@catholic.ac.kr
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
c-Jun;
gene expression;
promoter;
TSP-1;
YY-1
- MeSH:
Binding Sites/genetics;
Cell Line, Tumor;
DNA-Binding Proteins/*metabolism;
Down-Regulation/genetics;
Electrophoretic Mobility Shift Assay;
Genes, Reporter/genetics;
Humans;
Luciferases/analysis/genetics;
Promoter Regions (Genetics)/*genetics;
Proto-Oncogene Proteins c-jun/genetics/*metabolism;
Repressor Proteins/*metabolism;
Research Support, Non-U.S. Gov't;
Sequence Deletion/genetics;
Thrombospondin 1/*genetics/metabolism;
Transcription Factor AP-1/metabolism;
Transcription Factors/*metabolism
- From:Experimental & Molecular Medicine
2004;36(4):300-310
- CountryRepublic of Korea
- Language:English
-
Abstract:
Thrombospondin-1 (TSP-1) level is tightly regulated at the transcriptional level. To determine the detailed molecular mechanisms of TSP-1 expression, nine serial 5'-deletion constructs of the human genomic tsp-1 promoter (nucleotides -2,220 to +756) were prepared, inserted into luciferase reporter plasmids, and transiently transfected into the Hep3B human hepatocarcinoma cell. Among the nine 5'-deletion constructs, pTSP-Luc-4 (-767~+756) had consistently decreased luciferase activity with or without PMA stimulation, whereas a further truncated construct [pTSP-Luc-4' (-407~+756)] had increased levels of expression. By searching the nucleotides from -767 to -407, a consensus binding sequence (5'-CCATTTT-3') for the repressor Yin Yang-1 (YY-1) at nucleotide -440 was identified. The suppression induced by this site was weakened in the presence of the region upstream of nucleotide -767 (pTSP-Luc-1 and -2). Nuclear protein directly bound to an oligonucleotide containing the repressive YY-1 sequence but the binding capacity of the sequence was decreased by the increased c-Jun levels. Moreover, proteins immunoprecipitated with anti-YY-1 revealed an interaction between c-Jun and YY-1 factor. These data suggest that the repressive YY-1 site of the tsp-1 promoter could not be functional via activating positive cis-elements on the upstream from this site and weakened via c-Jun/YY-1 interactions.
