Hormones and nutrients regulate acetyl-CoA carboxylase promoter I in rat primary hepatocytes.
This study investigated the regulation of acetyl-CoA carboxylase (ACC) promoter activity by hormones and nutrients. Genomic clones including promoter I (PI) of the ACC gene were isolated and sequenced. ACC PI fragments (-1,049/+100 or -220/+21 bp) were subcloned into the pGL3-Basic vector that includes luciferase as a reporter gene. The ACC PI/luciferase chimeric plasmids were transfected into primary rat hepatocytes using lipofectin. Insulin treatment increased the activity of -1,049/+ 100 and -220/+21 ACC PI by 3.0- and 3.5-fold, respectively, compared to the control. The activity of both constructs was also increased by dexamethasone (Dex) and triiodothyronine (T3), with the greatest effects seen with all three hormones present. With -1,049/+100 or -220/+21 ACC PI, the addition of glucose increased luciferase activity compared to glucose-free control (p<0.05). On the other hand, polyunsaturated fatty acids (PUFA) reduced the activity of the -1,049/+100 ACC PI construct, with eicosapentaenoic acid and docosahexaenoic acid showing the greatest effect (about 70% of the control). However, the addition of PUFA to the culture media did not affect the activity of -220/+21 ACC PI. Therefore, insulin, Dex, T3, glucose, and PUFA regulate ACC gene expression, at least in part, through the PI promoter.
Kim
Youn-Jung
YJ
Department of Food and Nutritional Sciences, Ewha Women's University, Daehyndong 11-1 Sudaemun-ku, Seoul, 120-750, Korea.
Lee
Mak-Soon
MS
Lee
Hyun-Jung
HJ
Wu
Yue
Y
Freake
Hedley C
HC
Chun
Hyang-Sook
HS
Kim
Yangha
Y
D000103:Acetyl-CoA Carboxylase / Q000235:genetics*; D000818:Animals; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D005947:Glucose / Q000494:pharmacology; D022781:Hepatocytes / Q000201:enzymology*; D006728:Hormones / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D008297:Male; D009747:Nutritional Physiological Phenomena; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D014162:Transfection; D014284:Triiodothyronine / Q000494:pharmacology
D005231:Fatty Acids, Unsaturated; D006728:Hormones; D007328:Insulin; D012333:RNA, Messenger; D014284:Triiodothyronine; D003907:Dexamethasone; D000103:Acetyl-CoA Carboxylase; D005947:Glucose