共查询到20条相似文献,搜索用时 31 毫秒
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The E-box like sterol regulatory element mediates the suppression of human Delta-6 desaturase gene by highly unsaturated fatty acids 总被引:3,自引:0,他引:3
Nara TY He WS Tang C Clarke SD Nakamura MT 《Biochemical and biophysical research communications》2002,296(1):111-117
Delta-6 Desaturase (D6D) catalyzes the first step of the synthesis of highly unsaturated fatty acids (HUFA) that play pivotal roles in many biological functions. The D6D expression is under feedback regulation by dietary HUFA. We co-transfected D6D promoter-reporter constructs to HepG2 cells with an expression vector of nuclear form sterol regulatory element binding protein-1c (SREBP-1c). A 90-bp region of the D6D promoter was required for the activation by SREBP-1c as well as for the suppression of the promoter activity by HUFA. The region contained two candidates of sterol regulatory element (SRE). Mutation analysis identified E-box like SRE (SRE-2) as essential for both SREBP-1c activation and HUFA suppression. SRE-2 has a core sequence of CAGCAG, and is also conserved in stearoyl CoA desatruases. Because HUFA are primarily incorporated into phospholipids (PL), our results suggest that the primary role of SREBP-1c in liver is the regulation of fatty acid supply for PL rather than for triglycerides. 相似文献
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R J Denver L Ouellet D Furling A Kobayashi Y Fujii-Kuriyama J Puymirat 《The Journal of biological chemistry》1999,274(33):23128-23134
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The role of liver X receptor-alpha in the fatty acid regulation of hepatic gene expression 总被引:7,自引:0,他引:7
Pawar A Botolin D Mangelsdorf DJ Jump DB 《The Journal of biological chemistry》2003,278(42):40736-40743
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Single nucleotide resolution of sterol regulatory region in promoter for 3-hydroxy-3-methylglutaryl coenzyme A reductase 总被引:4,自引:0,他引:4
T F Osborne 《The Journal of biological chemistry》1991,266(21):13947-13951
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Thyroid hormones (THs) have a wide variety of essential roles in vertebrates, ranging from the regulation of key metabolic processes to cell proliferation and apoptosis. The classical mechanism of action of THs is genomic; 3,5,3'-triiodothyronine (T3) binds to specific nuclear receptors (TRs) and modifies the expression of specific genes. Recently, a new category of mechanisms, termed nongenomic, has been discovered for T3. These mechanisms include, among others, the rapid activation of signal transduction pathways, such as PI3K/Akt and MAPK, which eventually lead to cell proliferation. These effects are mediated in some cell types by a plasma membrane receptor, identified as integrin αvβ3, and in other cell types by cytoplasmic TRβ1. The aim of this work was to analyze the effect of T3 on the cell growth of chick embryo hepatocytes at two different stages of development, 14 and 19 days, and to determine the activation of the signal transduction pathways, focusing on the potential involvement of a plasma membrane receptor and the possible participation of PI3K/Akt and reactive oxygen species (ROS). Our results clearly show that T3 stimulates cell proliferation at both stages of development through the activation of the PI3K/Akt pathway and the production of small amounts of ROS, which operate as effective second messengers. Moreover, we prove that these effects are not initiated at the plasma membrane receptor for T3. 相似文献
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In studies using primary cultures of adult rat hepatocytes in serum-free medium, peroxisomal fatty acyl-CoA oxidase activity was not altered by the presence of 3,5,3'-triiodothyronine, whereas time- and dose-dependent increases in the thyroid hormone-responsive enzyme mitochondrial glycero-3-phosphate dehydrogenase were seen. Activity of peroxisomal oxidase was stimulated with clofibric acid in the absence of 3,5,3'-triiodothyronine. The results demonstrate that hepatic peroxisomal fatty acyl-CoA oxidase activity is not directly regulated by 3,5,3'-triiodothyronine and that stimulation of peroxisomal fatty acyl-CoA oxidase activity by clofibric acid does not require thyroid hormone. 相似文献
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