Sp1 mediates repression of the resistin gene by PPARgamma agonists in 3T3-L1 adipocytes.
Resistin is an adipokine related to obesity and insulin resistance. Expression of the resistin gene is repressed by the treatment of peroxisome proliferator-activated receptor gamma (PPARgamma) agonists, thiazolidinediones (TZDs). In this study, we investigated the mechanism by which TZDs inhibit the resistin gene expression. Resistin gene expression was decreased by TZD in fully differentiated 3T3-L1 adipocytes, which was abolished after treatment of cycloheximide (a protein synthesis inhibitor). TZD could not repress the expression of the resistin gene in the presence of mithramycin A (an Sp1 binding inhibitor). Sp1 binding site of the resistin promoter (-122/-114bp) was necessary for the repression. Further investigation of the effect of TZDs on the modification of Sp1 showed that the level of O-glycosylation of Sp1 was decreased in this process. These results suggest that PPARgamma activation represses the expression of the resistin gene by modulating Sp1 activity.
Chung
S S
SS
Genome Research Center for Diabetes and Endocrine Disease, Clinical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea.
Choi
H H
HH
Cho
Y M
YM
Lee
H K
HK
Park
K S
KS
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D005786:Gene Expression Regulation / Q000187:drug effects; D006031:Glycosylation; D007333:Insulin Resistance; D051379:Mice; D047495:PPAR gamma / Q000819:agonists / Q000235:genetics* / Q000378:metabolism; D008926:Plicamycin / Q000031:analogs & derivatives / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D052243:Resistin / Q000096:biosynthesis / Q000235:genetics*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D016329:Sp1 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D045162:Thiazolidinediones / Q000494:pharmacology
D047495:PPAR gamma; D052243:Resistin; D016329:Sp1 Transcription Factor; D045162:Thiazolidinediones; C066851:mithramycin A; D008926:Plicamycin