Yang Q Y, Chen T, Chen Y B, Lan D L
Pol J Vet Sci. 2016 Dec 1;19(4):753-761. doi: 10.1515/pjvs-2016-0095.
The NOD-like receptor (NLR) family caspase recruitment domain-containing 5 (NLRC5) is one of the newly discovered and largest NLR family members. The NLRC5 has recently received extensive attention because of its important role in regulating innate and adaptive immune responses. The NLRC5 in many vertebrates, such as humans, mice, cattle, and horses, has already been proven and studied. However, the NLRC5 gene characteristics of pigs remain unclear. Thus, we completely cloned the NLRC5 cDNA sequence of the pig using the rapid amplification of cDNA ends(RACE) technology. A characteristic and tissue expression analysis was also conducted on the pig sequence. The sequence analysis showed that the complete cDNA sequence of the NLRC5 of the pig is 6638 bp, and the open reading frame is 5538 bp which encoded 1846 amino acids. The protein prediction analysis indicates that the overall performance of the NLRC5 protein of the pig is hydrophilic and possesses a typical nucleotide binding and oligomerization domain(NBD) and 20 leucine-rich repeats(LRRs). The homology analysis result indicates that the NLRC5 transcript in pigs is highly homologous to cattle, sheep, macaques, and humans, and accounts for around 80%. The genetic evolutionary tree analysis shows that the NLRC5 transcript in pigs has the closest evolutionary relationship with cattle and sheep. Further tissue expression analysis shows that immune organ systems (e.g., lymph node and spleen) and mucosa organs (e.g., intestinal lymph node, stomach, and lungs) possess high expressions with NLRC5 mRNA. The result of this study indicates that the NLRC5 transcript in pigs is relatively conservative among mammals and may play a vital role in immune reaction, which provides a basis for further studies on the NLRC5 function in the pig immune system and the role in comparative immunity.
核苷酸结合寡聚化结构域样受体（NLR）家族含半胱天冬酶募集结构域蛋白5（NLRC5）是新发现的最大的NLR家族成员之一。由于NLRC5在调节先天性和适应性免疫反应中起重要作用，最近受到了广泛关注。NLRC5在许多脊椎动物，如人类、小鼠、牛和马中，已经得到证实和研究。然而，猪的NLRC5基因特征仍不清楚。因此，我们利用cDNA末端快速扩增（RACE）技术，完整克隆了猪的NLRC5 cDNA序列。并对猪的序列进行了特征和组织表达分析。序列分析表明，猪NLRC5的完整cDNA序列为6638 bp，开放阅读框为5538 bp，编码1846个氨基酸。蛋白质预测分析表明，猪NLRC5蛋白总体表现为亲水性，具有典型的核苷酸结合和寡聚化结构域（NBD）以及20个富含亮氨酸的重复序列（LRR）。同源性分析结果表明，猪的NLRC5转录本与牛、羊、猕猴和人类高度同源，同源性约为80%。遗传进化树分析表明，猪的NLRC5转录本与牛和羊的进化关系最为密切。进一步的组织表达分析表明，免疫器官系统（如淋巴结和脾脏）和黏膜器官（如肠淋巴结、胃和肺）中NLRC5 mRNA表达较高。本研究结果表明，猪的NLRC5转录本在哺乳动物中相对保守，可能在免疫反应中起重要作用，为进一步研究NLRC5在猪免疫系统中的功能及在比较免疫学中的作用提供了依据。
