摘要
小肠型脂肪酸结合蛋白对长链脂肪酸具有高度的亲和力,参与脂肪酸的吸收和细胞内转运。利用cDNA末端快速扩增(RACE)技术并结合同源克隆策略,克隆到了编码猪小肠型脂肪酸结合蛋白基因(I-FABP)的全长cDNA序列(GenBank接受号:AY960624),并对系统发育关系等进行了生物信息学分析。猪I-FABP基因的cDNA序列全长614 bp,其中包括399 bp的开放式读码框(ORF),43 bp的5′末端非编码区(5′ URT)和172 bp的3′末端非编码区(3′ URT),编码132个氨基酸残基蛋白,在氨基酸水平上与其他物种的I-FABP具有高度的同源性。以邻接法(Neigbor-Joining, NJ)所构建的系统发育关系表明,猪I-FABP与其他物种的I-FABP属于同一类群,且与人的遗传距离最近。Northern杂交和半定量RT-PCR分析发现,猪I-FABP在猪体组织中出现约620 bp大小的转录本,且在猪体组织中广泛存在,但在小肠组织中表达量最为丰富。
The intestinal fatty acid-binding protein （I-FABP） shows binding specificity for long-chain fatty acids and is proposed to be involved in the uptake of dietary fatty acids and their intracellular transport. In this study, the full-length cDNA of I-FABP was cloned from pig intestine by homology cloning approach combined with 3＇ and 5＇ RACE. Sequence analysis and bioinformatics study showed that this cDNA contained 614 nucleotides, with a 399 bp open reading frame （ORF） flanked by a 43 bp 5＇ UTR and a 172 bp 3＇ UTR. The encoded 132 amino acids of pig I-FABP with a molecular weight of approximately 15 kDa shared a high sequence identity of 68%-85% with those of other species. In addition, the phylogenetical analysis also indicated that the pig I-FABP was in the same branch with those of other species. The tissue-specific expression of pig I-FABP was measured by Northern hybridization and semi-quantitative RT-PCR. The results demonstrated that pig I-FABP mRNA was extensively present in various tissues, but I-FABP transcript of approximately 620 bp was more abundant in intestine than in other tissues.
基金
This work was supported by the 10th Five Years Key Programs for Science and Technology Development of China(No.2002BA514A-1-2)
