Studies on the physiological function of avian fatty acid binding protein and regulation of gene expression by PPAR-α

禽类脂肪酸结合蛋白生理功能及PPAR-α调控基因表达的研究

• 批准号: 13460125
• 负责人: OKUMURA Jun-ichi
• 金额: $ 10.82万
• 依托单位: Nagoya Bunri University (2002-2003)Nagoya University (2001)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13460125/
• 关键词: Fatty acid binding protein; FABP; Chicken; Liver; PPAR-α; Gene expression; Translational regulation; Hatching; 転写; プロモーター; 遊離脂肪酸; 鳥類; C; EBP-α; 脂質代謝; ペルオキシソーム

Fatty acid-binding proteins (FABPs) are important factors which regulate the cellular uptake and concentration of fatty acids and lipid metabolism. In avian species, two types of fatty acid binding proteins, L-FABP and Lb-FABP exist in the liver. In the present study, therefore, in order to make it clear the physiological function of avian FAB we tried to detremine 1)cDNA sequences of two FABPs, 2).nutritional and physiological factors affecting their expression, 3)the relevance of PPAR-α for transcription regulation. The cloned cDNA fragments of L-FABP and Lb-FABP coded 125 and 126 amino acids, respectively. The L-FABP mRNA were detected in the liver and intestine while Lb-FABPmRNA was expressed only in the liver. The mRNA abundance of both FABPs were steeply increased during hatching stage. However, the aging, sex-difference and laying performance did not influence the expression of both FABPs, showing that L-FABP and Lb-FABP stably express after the birth. To determine the nutritional regulation of FABPs, chicks were reared under the various nutritional conditions. The fasting decreased mRNA abundance of both FABPs in chicks, but the ingestion of high-fat diet and peroxisome proliferators Wy-14,643 had no influence of the mRNA abundance. There were no remarkable change of hepatic PPAR-α mRNA abundance in any conditions. The 5' -untranslated regions from -566bp to +1 for L-FABP and from -943bp to +1 for Lb-FABP were also cloned and sequenced. It is reported that the rat L-FABP gene contains an peroxisome proliferator response element (PPRE) at -76 to -66 kb. Surprisingly, PPRE were not observed in the chicken L-FABP gene as well as Lb-FABP gene. These results suggest that PPAR-a might not involved in the transcriptional regulation of chicken L-FABP and Lb-FABP gene expression.

脂肪酸结合蛋白(FABP)是调节细胞内脂肪酸摄取、浓度和脂类代谢的重要因子。在鸟类中，肝脏中存在两种脂肪酸结合蛋白，即L-FABP和Lb-FABP。因此，在本研究中，为了弄清禽类FAB的生理功能，我们试图1)两个FABP的α序列，2)影响其表达的营养和生理因素，3)PPAR-FAB与转录调控的相关性。克隆的L-FABP和Lb-FABP基因片段分别编码125和126个氨基酸。L-FABP基因在肝脏和肠道中均有表达，而Lb-FABP基因只在肝脏中表达。在孵化期，两种FABP的mRNA丰度都急剧增加。而年龄、性别差异和产蛋性能对两种FABP的表达没有影响，说明L-FABP和Lb-FABP在出生后稳定表达。为了确定FABPs的营养调节作用，在不同营养条件下饲养雏鸡。禁食降低了雏鸡两种FABP的mRNA丰度，但摄入高脂饲料和过氧化物酶体增殖剂Wy-14,643对其mRNA丰度没有影响。肝脏PPAR-α基因丰度在任何条件下均无明显变化。同时克隆了L-FABP的-566bp至+1和lb-FABP的-943bp至+1的5‘非翻译区。据报道，大鼠L-FABP基因含有一个在-76~-66kb之间的过氧化物酶体增殖物反应元件。令人惊讶的是，在鸡L-FABP基因和Lb-FABP基因中没有检测到PPRE。这些结果表明，PPAR-a可能不参与鸡L-FABP和Lb-FABP基因表达的转录调控。