Document Detail


Regulation of vitamin A metabolism-related gene expression.
MedLine Citation:
PMID:  11242473     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cellular retinol-binding protein, type II (CRBPII) is abundantly expressed in the small intestinal epithelial cells and plays a pivotal role in intestinal absorption and metabolism of retinol and beta-carotene. In the 5'-flanking region of rat CRBPII gene, two DR-1 type elements which consist of a direct repeat of the AGGTCA-like motif spaced by a single nucleotide have been identified as putative binding sites for a heterodimer of peroxisome proliferator-activated receptor (PPAR) and retinoid X-receptor (RXR). We found that CRBPII levels were elevated in the residual jejunal segment of rats subjected to jejunal bypass operation, where a concomitant increase in the apoprotein B levels occurred. This result suggested that CRBPII expression was enhanced by a condition where fat absorption was stimulated. Indeed, dietary fat (especially unsaturated fatty acids) has been shown to induce CRBPII gene expression in the jejunum. Nuclear run-on assays revealed that this increase of CRBPII mRNA levels by a high-fat diet was the result of the induction of the gene transcription through the rise in PPARalpha expression level as well as the increase in its ligand levels. Electrophoretic mobility shift assay using the DR-1 type cis-elements of CRBP II gene showed that PPARalpha-RXRalpha heterodimer was capable of binding to these elements, and that nuclear extracts from the jejunum of rats fed the high-fat diet gave greater density of retarded bands than those of rats fed a fat-free diet. We also found that the expression of PPARdelta was rather reduced by dietary fat. Thus, CRBPII gene expression is regulated predominantly by dietary fatty acids.
Authors:
S Takase; K Suruga; T Goda
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The British journal of nutrition     Volume:  84 Suppl 2     ISSN:  0007-1145     ISO Abbreviation:  Br. J. Nutr.     Publication Date:  2000 Dec 
Date Detail:
Created Date:  2001-03-12     Completed Date:  2001-03-22     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0372547     Medline TA:  Br J Nutr     Country:  England    
Other Details:
Languages:  eng     Pagination:  S217-21     Citation Subset:  IM    
Affiliation:
Department of Nutrition, Siebold University of Nagasaki, Nagasaki 851-2195, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Chick Embryo
Dietary Fats / metabolism*
Fatty Acids, Unsaturated / metabolism
Gene Expression Regulation*
Humans
Intestinal Absorption*
Jejunum / metabolism*
RNA, Messenger / metabolism
Rats
Receptors, Cytoplasmic and Nuclear / genetics,  metabolism
Receptors, Retinoic Acid / genetics,  metabolism
Retinoid X Receptors
Retinol-Binding Proteins / genetics*
Retinol-Binding Proteins, Cellular
Transcription Factors / genetics,  metabolism
Vitamin A / metabolism*
Chemical
Reg. No./Substance:
0/Dietary Fats; 0/Fatty Acids, Unsaturated; 0/RBP2 protein, human; 0/RNA, Messenger; 0/Rbp2 protein, rat; 0/Receptors, Cytoplasmic and Nuclear; 0/Receptors, Retinoic Acid; 0/Retinoid X Receptors; 0/Retinol-Binding Proteins; 0/Retinol-Binding Proteins, Cellular; 0/Transcription Factors; 11103-57-4/Vitamin A

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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