Starvation and feeding a high-carbohydrate, low-fat diet regulate the expression sterol regulatory element-binding protein-1 in chickens.
In mammalian liver, the mature form of sterol regulatory element-binding protein-1c (SREBP-1c) is an important activator of a wide array of genes involved in triacylglycerol biosynthesis. Starvation and feeding a high-carbohydrate, low-fat diet modulate the concentration of mature SREBP-1c primarily by a pretranslational mechanism. It is not known whether alterations in nutritional status regulate the concentration of SREBPs in nonmammalian species. In this study, we found that in previously starved chicks, feeding a high-carbohydrate, low-fat diet stimulated a robust increase (14-fold at 5 h of feeding) in the concentration of mature SREBP-1 in liver. Feeding a high-carbohydrate, low-fat diet also increased the concentration of precursor SREBP-1 and SREBP-1 messenger RNA in chick liver; however, the magnitude of this effect was substantially lower than that observed for mature SREBP-1. DNA binding experiments demonstrated that 3 protein complexes containing SREBP bound the acetyl-CoA carboxylase-alpha (ACCalpha) sterol regulatory element (SRE) in chick liver and that the binding activity of 2 of these complexes was increased by consumption of a high-carbohydrate, low-fat diet. Additional analyses showed that feeding a high-carbohydrate, low-fat diet had no effect on the concentration of mature SREBP-2 and the binding of SREBP-2 to the ACCalpha SRE in chick liver. These results indicate that alterations in the concentration of mature SREBP-1 play a role in mediating the effects of starvation and feeding a high-carbohydrate, low-fat diet on ACCalpha transcription in chick liver and that diet-induced changes in mature SREBP-1 concentration in chick liver are mediated primarily by a posttranslational mechanism.
Zhang
Yanqiao
Y
Department of Biochemistry and Molecular Pharmacology, School of Medicine, West Virginia University, Morgantown, WV 26506, USA.
Hillgartner
F Bradley
FB
D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002645:Chickens / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018752:Diet, Fat-Restricted; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D007527:Isoenzymes / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013217:Starvation / Q000378:metabolism*; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D004040:Dietary Carbohydrates; D007527:Isoenzymes; D009687:Nuclear Proteins; D012333:RNA, Messenger; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors; D000103:Acetyl-CoA Carboxylase