绵羊IGFBP-3基因的克隆及序列分析

Cloning and Sequence Analysis of IGFBP-3 Gene in Sheep

旨在克隆IGFBP-3基因的CDS序列及其生物信息学分析,试验以凉山半细毛羊为研究对象,采用RT-PCR方法克隆了IGFBP-3基因的CDS全序列,生物信息学方法深入分析其序列。结果表明:IGFBP-3基因的CDS序列为882bp,编码293个氨基酸,与牛、人、鼠的CDS同源性分别为94%、83%、81%,氨基酸序列同源性分别为91%、77%、79%,GenBank登录号为FJ752574;IGFBP-3基因的氨基酸分子量为31.5KD,理论等电点(pI)为8.98;进化分析显示与牛、山羊等哺乳动物关系较近,与鸡、鱼类等亲缘关系较远;IGFBP-3基因存在明显的疏水性区域和亲水性区域,有一个信号肽、25个磷酸化位点、7个N-糖基化位点和4个O-糖基化位点;二级结构分析显示无规卷曲、α-螺旋和β-折叠区域分别为73.04%、13.99%、12.97%;三级结构分析显示存在IGFBP-N和甲状腺球蛋白-Ⅰ型功能域。为进一步研究绵羊IGFBP-3基因的功能奠定基础。

In order to clone the CDS sequence of IGFBP - 3 gene and bioinforrnatic analysis, the whole CDS sequence of IGFBP - 3 gene was cloned by using the RT - PCR method with Liangshan semi - fine wool sheep. Further efforts were made to analyse its sequences in bioinformatics. The results showed that the CDS sequence of IGFBP -3 gene was 882 bp, encoding 293 amino acids, being 94% , 83% and 81% respectively about CDS homology compared with bovine, human and rat, was FJ752574 of GenBank accession number. The amino acid sequence analysis revealed that it＇ s relationship was near mammals about cattle and goat, and far more chicken, fish ere, its homology was 91% , 77% and 79% respectively. Compared with bovine, human and rat, its molecular weight was 31. 5 KD, isoelectric point was 8. 98, with obvious hydrophobic and hydrophilic regions, a signal peptide, a transmembrane region, 25 sites of phosphorylation, 7 sites of N - glycosylation and 4 sites of O - glycosylation. There were forecast that the random coil, ct - helix and ~ - sheet region were 73. 04%, 13. 99% , 12. 97% respectively in secondary structure, a IGFBP_ N domain and a thyroglobulin - I type of domain were in tertiary struc- ture. It provides a scientific basis to further study the function of IGFBP -3 gene in sheep.