Field F J, Born E, Murthy S, Mathur S N
Department of Internal Medicine and Veterans Administration, University of Iowa, Iowa City, IA 52242, USA.
J Lipid Res. 2001 Jan;42(1):1-8.
Gene expression of sterol regulatory element-binding proteins 1a, 1c, and 2 (SREBP-1a, -1c, and -2) and of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) synthase, HMG-CoA reductase, and the low density lipoprotein (LDL) receptor was examined in hamster small intestine. SREBP-1c transcript predominated over SREBP-1a. mRNA levels for SREBP-1a, -1c, and -2, LDL receptor, and HMG-CoA synthase were highest in jejunum and ileum. Expression of SREBP-1a and SREBP-1c was highest in cells of the upper villus and decreased in cells of the lower villus. Gene expression of SREBP-2 was lowest in cells of the upper villus and increased in cells of the lower villus. Ileal SREBP-2 gene expression was highest in cells of the midvillus. mRNA levels for HMG-CoA synthase and the LDL receptor followed a pattern similar to that of SREBP-2. A positive correlation existed between SREBP-2 gene expression and rates of cholesterol synthesis. Fatty acid synthesis was highest in jejunum and ileum, correlating positively with the expression of SREBP-1c. Sterol influx into intestinal cells decreased mRNA levels of SREBP-2, HMG-CoA reductase, HMG-CoA synthase, and LDL receptor. In ileum, sterol influx decreased gene expression of SREBP-1a and increased expression of SREBP-1c. The results suggest that SREBP-2 regulates cholesterol synthesis in the small intestine. SREBP-1a is a minor transcript and its expression does not correlate with cholesterol-synthesizing activity. SREBP-1c is a major transcript in small intestine and its expression along the length of the gut correlates with fatty acid synthesis. Sterols regulate gene expression of sterol-responsive genes, including SREBP-2, in small intestine. - Field, F. J., E. Born, S. Murthy, and S. N. Mathur. Gene expression of sterol regulatory element-binding proteins in hamster small intestine. J. Lipid Res. 2001. 42: 1;-8.
在仓鼠小肠中检测了固醇调节元件结合蛋白1a、1c和2（SREBP - 1a、- 1c和- 2）以及3 - 羟基- 3 - 甲基戊二酰辅酶A（HMG - CoA）合酶、HMG - CoA还原酶和低密度脂蛋白（LDL）受体的基因表达。SREBP - 1c转录本在数量上超过SREBP - 1a。SREBP - 1a、- 1c和- 2、LDL受体以及HMG - CoA合酶的mRNA水平在空肠和回肠中最高。SREBP - 1a和SREBP - 1c的表达在上部绒毛细胞中最高，而在下部绒毛细胞中降低。SREBP - 2的基因表达在上部绒毛细胞中最低，而在下部绒毛细胞中升高。回肠中SREBP - 2的基因表达在中部绒毛细胞中最高。HMG - CoA合酶和LDL受体的mRNA水平呈现出与SREBP - 2相似的模式。SREBP - 2基因表达与胆固醇合成速率之间存在正相关。脂肪酸合成在空肠和回肠中最高，与SREBP - 1c的表达呈正相关。固醇流入肠道细胞会降低SREBP - 2、HMG - CoA还原酶、HMG - CoA合酶和LDL受体的mRNA水平。在回肠中，固醇流入会降低SREBP - 1a的基因表达并增加SREBP - 1c的表达。结果表明，SREBP - 2调节小肠中的胆固醇合成。SREBP - 1a是次要转录本，其表达与胆固醇合成活性无关。SREBP - 1c是小肠中的主要转录本，其在肠道全长中的表达与脂肪酸合成相关。固醇调节小肠中固醇反应性基因（包括SREBP - 2）的基因表达。- 菲尔德，F. J.，E. 博恩，S. 穆尔蒂，和S. N. 马图尔。仓鼠小肠中固醇调节元件结合蛋白的基因表达。《脂质研究杂志》。2001年。42卷：1 - 8页。
