Sabath D E, Spangler E A, Rubin E M, Stamatoyannopoulos G
Department of Medicine, University of Washington, Seattle 98195.
Blood. 1993 Nov 1;82(9):2899-905.
zeta-Globin is the embryonic form of the alpha chain of hemoglobin. Transgenic mice generated with zeta-globin constructs containing the zeta-globin gene, 557 bp of 5' flanking sequence, and 2-kb of 3' flanking sequence linked to the beta-globin locus control region hypersensitive site 2 (HS2) expressed human zeta-globin only in embryonic yolk sac erythroid tissue, and not in definitive erythroid tissue in the fetal liver or in adult peripheral blood. To determine what sequences in the 5' flanking region of the zeta-globin gene might be important for developmental specificity, a series of 5' deletion constructs of the zeta-globin gene were made and used to generate transgenic mice. The 5' ends of these constructs were located 417, 207, and 128 bp 5' to the zeta-globin transcriptional start site, and HS2 was included to increase the level of erythroid-specific expression. In all lines of mice tested, human zeta-globin was expressed only in embryonic tissue, and not in fetal livers or in adult peripheral blood. Expression was independent of copy number and appeared to be dependent on the site of transgene insertion. These data suggest that the proximal 128 bp of the zeta-globin promoter is sufficient to properly regulate zeta-globin expression during development.
ζ-珠蛋白是血红蛋白α链的胚胎形式。用含有ζ-珠蛋白基因、557 bp的5'侧翼序列和2 kb的3'侧翼序列并与β-珠蛋白基因座控制区超敏位点2（HS2）相连的ζ-珠蛋白构建体产生的转基因小鼠，仅在胚胎卵黄囊红系组织中表达人ζ-珠蛋白，而不在胎儿肝脏或成人外周血的定型红系组织中表达。为了确定ζ-珠蛋白基因5'侧翼区域中的哪些序列可能对发育特异性很重要，制备了一系列ζ-珠蛋白基因的5'缺失构建体，并用于产生转基因小鼠。这些构建体的5'末端位于ζ-珠蛋白转录起始位点上游417 bp、207 bp和128 bp处，并包含HS2以提高红系特异性表达水平。在所有测试的小鼠品系中，人ζ-珠蛋白仅在胚胎组织中表达，而不在胎儿肝脏或成人外周血中表达。表达与拷贝数无关，似乎取决于转基因插入位点。这些数据表明，ζ-珠蛋白启动子近端的128 bp足以在发育过程中正确调节ζ-珠蛋白的表达。
