中文摘要：

淋巴细胞趋化因子（XCL1）是C族趋化因子的一员，可由CD8＋T细胞、NK细胞、γδT细胞、肥大细胞等多种细胞产生，其趋化性主要作用于CD8＋T细胞和NK细胞。根据猪的EST数据库中猪XCL1基因序列，设计引物采用RT—PCR的方法从猪胸腺中扩增猪XCL1全基因序列，将其连接到pMD-19T载体上并测序，得到猪XCLl基因（GenBank登录号为EU743945）。猪XCL1cDNA大小为333bp，编码由110个氨基酸残基组成的多肽。该多肽序列含Chemokine-C、Chemokine、Chemokine-CC和SCY等功能域，与羊和人的氨基酸序列相似率分别为81．6％和68．4％。预测分析其为分泌蛋白，信号肽剪切位点在21A和22V。猪XCL1基因定位于猪4号染色体（CU468871），基因结构与人XCL1的相似，都由3个外显子组成。该基因ORF翻译起始处基本符合Kozak规则，ORF起始密码子上游同一相位有终止密码子，ORF后有1个加尾信号，预测得到4个可能的启动子，可能性高达85％～98％。总之，通过电子克隆与试验验证，成功地克隆了猪新基因XCL1。

英文摘要：

Chemokine （C motif） ligand 1（XCL1） is a small cytokine belonging to the C chemokine family that is also known as lymphotactin. XCL1 is produced by activated CD8（＋） T cells, NK cells, gamma delta T cells and masl cells, and its chemotactic activity seems primarily controlling movement of CD8（＋） T ceils and NK cells. This work reports the cloning and characterization of the porcine XCL1 cdNA. Porcine XCL1 cDNA was oblained by reverse transcription polymerase chain reaction （RT-PCR） from porcine thymus mRNA, using in silico cloning strategy based on pig dbEST. The complete open reading frame （ORF） of XCL1 contains 333 bp encoding a deduced 110 aa residues. The amino acid sequence of porcine XCL1 was characterized by Chemokine-C, Chemokine, Chemokine-CC and SCY domains. The putative porcine XCL1 protein shares a higher level of homology with its sheep （81.6% amino acid identity） than with its human （68.4% amino acid identity） counterpart, and is predicted as a secreted protein, with the most likely cleavage site between 21A and 22V of the N-terminus. The gene is composed of three exons, the general structure being observed to be similar to that of the human XCL1 gene. The gene was mapped to chromosome 4 （CU468871）. The porcine XCL1 gene has 4 putative promoters with possibility of 85%- 98%, a stop codon in the upstream of ORF , one Poly-A signal in the downstream of ORF, and basically accords with Kozak rule around the translation start of the ORF. In conclusion, by combining bioinformatits analyses with experimental verification, a novel porcine gene XCL1 was successfully cloned, and verified by a series of theoretical and experimental evidences.