Guan P, Burghes A H, Cunningham A, Lira P, Brissette W H, Neote K, McColl S R
Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, 43210, USA.
Genomics. 1999 Mar 15;56(3):296-302. doi: 10.1006/geno.1998.5635.
The chemokines are a group of chemotactic molecules that appear to regulate the directed movement of white blood cells in vitro and in vivo and may therefore play important roles in inflammation and immunity. The genes encoding the chemokines are clustered in close physical proximity to each other. A large cluster of human CC chemokine genes resides on chromosome 17. We have used this information in a positional cloning approach to identify novel chemokine genes within this cluster. We constructed a YAC contig encompassing the MIP-1alpha (HGMW-approved symbol SCYA3) gene region and used exon trapping and sequence analysis to isolate novel chemokine genes. Using this approach, a gene encoding a chemokine named MIP-4, based on its homology with MIP-1alpha (49.5% identity at the nucleotide level and 59.6% at the predicted amino acid level), was found. The MIP-4 gene (HGMW-approved symbol SCYA18) consists of three exons spread over 7.1 kb and is separated from the MIP-1alpha gene by 16 kb. The MIP-4 gene encodes a 750-bp mRNA that is expressed in lung and macrophages but not in brain or muscle. The mRNA encodes an 89-amino-acid protein and includes a predicted signal peptide of 21 amino acids. Recombinant or synthetic MIP-4 induced calcium mobilization in naive and activated T lymphocyte subpopulations in vitro. Injection of synthetic MIP-4 into the peritoneal cavity of mice led to the accumulation of both CD4(+) and CD8(+) T lymphocytes, but not monocytes or granulocytes. These observations provide new information concerning the arrangement of the CC chemokine gene cluster on human chromosome 17 and indicate that the MIP-4 gene product is chemotactic in vivo for both CD4(+) and CD8(+) T lymphocytes and may therefore be implicated in both humoral and cell-mediated immunity.
趋化因子是一类趋化分子，似乎在体外和体内调节白细胞的定向运动，因此可能在炎症和免疫中发挥重要作用。编码趋化因子的基因在物理位置上彼此紧密聚集。一大簇人类CC趋化因子基因位于17号染色体上。我们利用这一信息，采用定位克隆方法在该簇中鉴定新的趋化因子基因。我们构建了一个包含MIP-1α（HGMW批准符号为SCYA3）基因区域的酵母人工染色体（YAC）重叠群，并利用外显子捕获和序列分析来分离新的趋化因子基因。通过这种方法，发现了一个编码趋化因子的基因，根据其与MIP-1α的同源性（核苷酸水平上49.5%的同一性，预测氨基酸水平上59.6%的同一性）将其命名为MIP-4。MIP-4基因（HGMW批准符号为SCYA18）由三个外显子组成，分布在7.1 kb上，与MIP-1α基因相隔16 kb。MIP-4基因编码一个750 bp的mRNA，在肺和巨噬细胞中表达，但在脑或肌肉中不表达。该mRNA编码一个89个氨基酸的蛋白质，包括一个预测的21个氨基酸的信号肽。重组或合成的MIP-4在体外诱导未活化和活化的T淋巴细胞亚群中的钙动员。将合成的MIP-4注射到小鼠腹腔中导致CD4(+)和CD8(+) T淋巴细胞的积累，但不导致单核细胞或粒细胞的积累。这些观察结果提供了有关人类17号染色体上CC趋化因子基因簇排列的新信息，并表明MIP-4基因产物在体内对CD4(+)和CD8(+) T淋巴细胞具有趋化作用，因此可能与体液免疫和细胞介导免疫都有关。
