Overexpression and ribozyme-mediated targeting of transcriptional coactivators CREB-binding protein and p300 revealed their indispensable roles in adipocyte differentiation through the regulation of peroxisome proliferator-activated receptor gamma.
The cAMP-response element-binding protein-binding protein (CBP) and p300 are common coactivators for several transcriptional factors. It has been reported that both CBP and p300 are significant for the activation of peroxisome proliferator-activated receptor gamma (PPARgamma), which is a crucial nuclear receptor in adipogenesis. However, it remains unclear whether CBP and/or p300 is physiologically essential to the activation of PPARgamma in adipocytes and adipocyte differentiation. In this study, we investigated the physiological significance of CBP/p300 in NIH3T3 cells transiently expressing PPARgamma and CBP and in 3T3-L1 preadipocytes stably expressing CBP- or p300-specific ribozymes. In PPARgamma-transfected NIH3T3 cells, induction of expression of PPARgamma target genes such as adipocyte fatty acid-binding protein (aP2) and lipoprotein lipase (LPL) by adding thiazolidinedione was enhanced, depending on the amount of a CBP expression plasmid transfected. Expression of aP2 and LPL genes, as well as glycerol-3-phosphate dehydrogenase activity and triacylglyceride accumulation after adipogenic induction, was largely suppressed in 3T3-L1 adipocytes expressing either the CBP- or p300-specific active ribozyme, but not in inactive ribozyme-expressing cells. These data suggest that both CBP and p300 are indispensable for the full activation of PPARgamma and adipocyte differentiation and that CBP and p300 do not mutually complement in the process.
Takahashi
Nobuyuki
N
Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
Kawada
Teruo
T
Yamamoto
Takayuki
T
Goto
Tsuyoshi
T
Taimatsu
Aki
A
Aoki
Naohito
N
Kawasaki
Hiroaki
H
Taira
Kazunari
K
Yokoyama
Kazunari K
KK
Kamei
Yasutomi
Y
Fushiki
Tohru
T
D016475:3T3 Cells; D000123:Acetyltransferases / Q000378:metabolism*; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D000818:Animals; D050882:CREB-Binding Protein; D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D051548:Histone Acetyltransferases; D015151:Immunoblotting; D008024:Ligands; D008071:Lipoprotein Lipase / Q000378:metabolism; D051379:Mice; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016337:RNA, Catalytic / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013997:Time Factors; D015534:Trans-Activators / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D014280:Triglycerides / Q000378:metabolism; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor
D000123:Acetyltransferases; D050882:CREB-Binding Protein; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005993:Glycerolphosphate Dehydrogenase; D051548:Histone Acetyltransferases; D008024:Ligands; D008071:Lipoprotein Lipase; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D016337:RNA, Catalytic; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D014280:Triglycerides; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C082667:Fabp5 protein, mouse; C086936:Fabp7 protein, mouse; C494364:Crebbp protein, mouse