Yang H, Wang S, Liu Z, Wu M H, McAlpine B, Ansel J, Armstrong C, Wu G
Departments of Microbiology and Immunology, Emory University School of Medicine, GA 30322, Atlanta, USA.
Gene. 2001 Mar 7;265(1-2):133-45. doi: 10.1016/s0378-1119(01)00349-3.
The cell surface adhesion molecule human MUC18 (huMUC18 or Mel-CAM) has been postulated to play a key pathogenic role in metastatic melanoma progression. To establish an immunocompetent syngeneic mouse model that would greatly facilitate our understanding of the role of MUC18 in the metastatic behavior of melanoma, we cloned and characterized the mouse MUC18 (muMUC18) cDNA gene. The gene was amplified by RT-PCR and RACE of the poly(A)+RNA isolated from the mouse melanoma cell line B16F10/Queens. The cloned muMUC18 cDNA gene contained 28 nucleotides of 5'-UTR, 908 nucleotides of 3'-UTR, and an open reading frame (ORF) of 1947 nucleotides encoding a protein of 648 amino acids, which is two amino acids longer than huMUC18. The size of the muMUC18 mRNA is about 3 kb with a shorter 3'-UTR than the huMUC18 mRNA (about 3.3 kb). Besides, the sequence in the 3' UTR of the two mRNAs is diverse with only 31% identity. The 5'-UTR and coding sequences of the muMUC18 cDNA are 72.4 and 80.6% identical to those of huMUC18, respectively. The deduced amino acid sequence of the muMUC18 cDNA is 76.2% identical to that of huMUC18. The amino acid sequences deduced from MUC18 cDNA sequences from six other mouse melanoma cell lines are identical except one to three residues, suggesting that the muMUC18 cDNA sequence determined in this report is correct. The muMUC18 protein is predicted to be slightly more acidic than the human protein. The levels of muMUC18 mRNA and protein in nine mouse melanoma cell lines were directly proportional to their ability to establish metastatic colonies in lungs of syngeneic mice. Most biological functions of the muMUC18 may be similar to the huMUC18.
细胞表面黏附分子人MUC18（huMUC18或Mel-CAM）被认为在转移性黑色素瘤进展中起关键致病作用。为建立一个免疫健全的同基因小鼠模型，以极大地促进我们对MUC18在黑色素瘤转移行为中作用的理解，我们克隆并鉴定了小鼠MUC18（muMUC18）cDNA基因。通过从小鼠黑色素瘤细胞系B16F10/Queens分离的poly(A)+RNA进行RT-PCR和RACE扩增该基因。克隆的muMUC18 cDNA基因包含28个核苷酸的5'-UTR、908个核苷酸的3'-UTR以及一个1947个核苷酸的开放阅读框（ORF），编码一个648个氨基酸的蛋白质，比huMUC18长两个氨基酸。muMUC18 mRNA的大小约为3 kb，其3'-UTR比huMUC18 mRNA（约3.3 kb）短。此外，两种mRNA的3'UTR序列不同，同一性仅为31%。muMUC18 cDNA的5'-UTR和编码序列分别与huMUC18的5'-UTR和编码序列有72.4%和80.6%的同一性。muMUC18 cDNA推导的氨基酸序列与huMUC18的氨基酸序列有76.2%的同一性。从其他六个小鼠黑色素瘤细胞系的MUC18 cDNA序列推导的氨基酸序列除一到三个残基外均相同，表明本报告中确定的muMUC18 cDNA序列是正确的。预计muMUC18蛋白比人蛋白的酸性略强。九个小鼠黑色素瘤细胞系中muMUC18 mRNA和蛋白的水平与它们在同基因小鼠肺中形成转移瘤的能力直接相关。muMUC18的大多数生物学功能可能与huMUC18相似。
