| First Author | Yahagi N | Year | 1999 |
| Journal | J Biol Chem | Volume | 274 |
| Issue | 50 | Pages | 35840-4 |
| PubMed ID | 10585468 | Mgi Jnum | J:58899 |
| Mgi Id | MGI:1350555 | Doi | 10.1074/jbc.274.50.35840 |
| Citation | Yahagi N, et al. (1999) A crucial role of sterol regulatory element-binding protein-1 in the regulation of lipogenic gene expression by polyunsaturated fatty acids. J Biol Chem 274(50):35840-4 |
| abstractText | Dietary polyunsaturated fatty acids (PUFA) are negative regulators of hepatic lipogenesis that exert their effects primarily at the level of transcription. Sterol regulatory element-binding proteins (SREBPs) are transcription factors responsible for the regulation of cholesterol, fatty acid, and triglyceride synthesis. In particular, SREBP-1 is known to play a crucial role in the regulation of lipogenic gene expression in the liver. To explore the possible involvement of SREBP-1 in the suppression of hepatic lipogenesis by PUFA, we challenged wild-type mice and transgenic mice overexpressing a mature form of SREBP-1 in the liver with dietary PUFA. In the liver of wild-type mice, dietary PUFA drastically decreased the mature, cleaved form of SREBP-1 protein in the nucleus, whereas the precursor, uncleaved form in the membranes was not suppressed. The decreases in mature SREBP-1 paralleled those in mRNAs for lipogenic enzymes such as fatty acid synthase and acetyl-CoA carboxylase. In the transgenic mice, dietary PUFA did not reduce the amount of transgenic SREBP-1 protein, excluding the possibility that PUFA accelerated the degradation of mature SREBP-1. The resulting sustained expression of mature SREBP-1 almost completely canceled the suppression of lipogenic gene expression by PUFA in the SREBP-1 transgenic mice. These results demonstrate that the suppressive effect of PUFA on lipogenic enzyme genes in the liver is caused by a decrease in the mature form of SREBP-1 protein, which is presumably due to the reduced cleavage of SREBP-1 precursor protein. |
