Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, P. R. China.
Int J Biol Sci. 2012;8(1):49-58. doi: 10.7150/ijbs.8.49. Epub 2011 Nov 17.
The transporter associated with antigen processing (TAP) translocates antigenic peptides from the cytosol into the lumen of the endoplasmic reticular and plays a critical role in the major histocompatibility complex (MHC) class I molecule-mediated antigenic presentation pathway. In this study, the porcine TAP1 gene was mapped to the pig chromosome 7 (SSC7) and was closely linked to the marker SSC2B02 (retention fraction=43%, LOD=15.18). Subcellular localization of TAP1 by transient transfection of PK15 cells indicated that the TAP1 protein might be located in the endoplasmic reticulum (ER) in pig kidney epithelial cells (PK-15). Gene expression analysis by semi-quantitative RT-PCR revealed that TAP1 was selectively expressed in some immune and immune-related tissues. Quantitative real-time PCR (qRT-PCR) analysis revealed that this gene was up-regulated after treatments that mimic viral and bacterial infection (polyriboinosinic-polyribocytidylic acid (poly(I:C)) and lipopolysaccharide (LPS), respectively). In addition, elevated TAP1 expression was detected after porcine reproductive and respiratory syndrome virus (PRRSV) infection in porcine white blood cells (WBCs). One single nucleotide polymorphism (SNP) in exon 3 of TAP1 was detected in a Landrace pig population by Bsp143I restriction enzyme digestion. Different genotypes of this SNP had significant associations (P<0.05) with the red blood cell distribution width (RDW) of 1-day-old (1 d) pigs (P=0.0168), the PRRSV antibody level (PRRSV Ab) (P=0.0445) and the absolute lymphocyte count (LYM#) (P=0.024) of 17 d pigs. Our results showed that the TAP1 gene might have important roles in swine immune responses, and these results provide useful information for further functional studies.
抗原加工相关转运体（TAP）将抗原肽从细胞质中转运到内质网腔中，并在主要组织相容性复合体（MHC）I 类分子介导的抗原呈递途径中发挥关键作用。本研究将猪 TAP1 基因定位于猪染色体 7（SSC7）上，并与标记 SSC2B02 紧密连锁（遗传距离=43%，LOD=15.18）。通过 PK15 细胞的瞬时转染对 TAP1 的亚细胞定位表明，TAP1 蛋白可能位于猪肾上皮细胞（PK-15）的内质网（ER）中。半定量 RT-PCR 基因表达分析显示，TAP1 在一些免疫和免疫相关组织中选择性表达。定量实时 PCR（qRT-PCR）分析显示，该基因在模拟病毒和细菌感染（多聚肌苷酸-多聚胞苷酸（poly(I:C)）和脂多糖（LPS））的处理后被上调。此外，在猪繁殖与呼吸综合征病毒（PRRSV）感染猪白细胞（WBC）后检测到 TAP1 表达升高。通过 Bsp143I 限制性内切酶消化检测到 TAP1 外显子 3 中的一个单核苷酸多态性（SNP）。该 SNP 的不同基因型与 1 日龄（1 d）猪的红细胞分布宽度（RDW）（P=0.0168）、PRRSV 抗体水平（PRRSV Ab）（P=0.0445）和 17 日龄猪的绝对淋巴细胞计数（LYM#）（P=0.024）显著相关（P<0.05）。我们的结果表明，TAP1 基因可能在猪的免疫反应中具有重要作用，这些结果为进一步的功能研究提供了有用的信息。
