Regulatory Mechanisms of Gene Expression by Carbohydrates.
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Accession number;99A0562727
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| Title;Regulatory Mechanisms of Gene Expression by Carbohydrates. |
| Author;
YAMADA KAZUYA
(Fukui Med. Sch.)
NOGUCHI TAMIO
(Nagoya Univ., Grad. Sch.)
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Journal Title;Journal of Japanese Society of Nutrition and Food Science
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Journal Code:F0624A
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ISSN:0287-3516
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VOL.52;NO.3;PAGE.167-173(1999)
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| Figure&Table&Reference;TBL.1, REF.51 |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;Dietary carbohydrates regulate the expression of genes involved in carbohydrate and lipid metabolism. Although this regulation may be mediated by insulin, there is a considerable amount of evidence indicating that carbohydrates or their metabolites, and not insulin itself, are directly involved in gene regulation. The L-type isozyme (LPK) gene of pyruvate kinase, an important glycolytic enzyme, is a good example. This gene is expressed in liver, kidney, small intestine, and pancreatic .BETA.-cells, and is stimulated by carbohydrates such as glucose and fructose at both the transcriptional and post-transcriptional levels. Two cis-acting regulatory elements named L-II and L-III are required for transcriptional stimulation of the LPK gene by carbohydrates. Although the L-III element is itself responsive to carbohydrates, L-II functions as an accessory element. Both nuclear factor 1 proteins and hepatocyte nuclear factor 4 bind to the L-II element. Further studies have suggested that the former is involved in carbohydrate stimulation of the LPK gene. However, the L-III element binding protein that is involved in carbohydrate regulation remains to be clarified. Available evidence suggests that the carbohydrate signaling pathway to the LPK gene includes a glucose metabolite, possibly glucose 6-phosphate or xylulose 5-phosphate, as well as phosphorylation and dephosphorylation mechanisms. (author abst.) |
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