Greaves D R, Quinn C M, Seldin M F, Gordon S
Sir William Dunn School of Pathology, South Parks Road, Oxford, OX1 3RE, United Kingdom.
Genomics. 1998 Nov 15;54(1):165-8. doi: 10.1006/geno.1998.5546.
The glycoprotein macrosialin is expressed specifically in murine monocytes and macrophages. In the murine genome the macrosialin gene lies 877 bp 3' of the ubiquitously expressed elongation initiation factor 4A1 (eIF-4AI) gene on chromosome 11. The macrosialin gene promoter directs high-level expression in transiently transfected murine macrophage cell lines, but significant levels of expression are seen in nonmacrophage cell lines. The first intron of the gene encoding the human homologue of macrosialin, CD68, directs macrophage-specific expression when cloned downstream of the human CD68 gene promoter. Despite sharing extensive sequence homology with the human CD68 gene first intron, the murine macrosialin gene first intron does not act as a macrophage-specific enhancer when cloned downstream of the human CD68 or murine macrosialin promoters. We conclude that the genetic elements that are responsible for macrophage-specific gene expression are organized differently in the murine and human CD68 genes.
糖蛋白巨唾液酸蛋白在小鼠单核细胞和巨噬细胞中特异性表达。在小鼠基因组中，巨唾液酸蛋白基因位于11号染色体上普遍表达的延伸起始因子4A1（eIF-4AI）基因下游877 bp处。巨唾液酸蛋白基因启动子在瞬时转染的小鼠巨噬细胞系中指导高水平表达，但在非巨噬细胞系中也可见显著水平的表达。编码巨唾液酸蛋白人类同源物CD68的基因的第一个内含子，当克隆到人类CD68基因启动子下游时，指导巨噬细胞特异性表达。尽管与人类CD68基因的第一个内含子有广泛的序列同源性，但小鼠巨唾液酸蛋白基因的第一个内含子在克隆到人类CD68或小鼠巨唾液酸蛋白启动子下游时，并不作为巨噬细胞特异性增强子起作用。我们得出结论，负责巨噬细胞特异性基因表达的遗传元件在小鼠和人类CD68基因中的组织方式不同。
