Jorcyk C L, Garrett L J, Maroulakou I G, Watson D K, Green J E
Laboratory of Molecular Oncology, National Cancer Institute, FCRDC, Frederick, MD 21702-1201, USA.
Cell Mol Biol (Noisy-le-grand). 1997 Mar;43(2):211-25.
Ets-1, a developmentally-regulated protooncogene, is expressed in multiple tissues during different stages of mouse development and cellular differentiation including high levels in lymphoid organs and endothelium. The putative roles of this DNA-binding protein in lymphoid development and maturation, as well as in angiogenesis and tumor vascularization, suggest that the regulation of Ets-1 may be critical to understanding these important developmental processes. We have cloned the mouse Ets-1 5' flanking region which shows significant homology to the human 5' flanking region, including potential transcription factor binding sites. Various amounts of mouse Ets-1 5' flanking, exon and intron sequences have been fused to the E. coli lacZ reporter gene and introduced into the mouse germline to identify genomic regions which regulate the developmental and tissue-specific expression of Ets-1. The 2.4 kb 5' flanking region of Ets-1 directs lacZ expression to the folding neural tube of embryos at gestational day 8.5 which is identical to the endogenous expression pattern of Ets-1. However, at later times in gestation, up to 5.3 kb of 5' flanking region results only in aberrant expression and is not able to confer lacZ expression in lymphoid or vascular tissues. When the first exon and 9 kb of the first intron are included with 5' flanking sequences, using an enhancer-trap-strategy, lacZ expression is observed in developing vessels, meninges and choroid plexus which correlates to endogenous Ets-1 expression. Further characterization of the vascular-specific element contained within intron I will provide important insights into the mechanisms controlling gene expression during angiogenesis.
Ets-1是一种受发育调控的原癌基因，在小鼠发育和细胞分化的不同阶段于多种组织中表达，在淋巴器官和内皮中表达水平较高。这种DNA结合蛋白在淋巴发育和成熟以及血管生成和肿瘤血管形成中的假定作用表明，Ets-1的调控对于理解这些重要的发育过程可能至关重要。我们克隆了小鼠Ets-1的5'侧翼区域，该区域与人类5'侧翼区域显示出显著的同源性，包括潜在的转录因子结合位点。不同数量的小鼠Ets-1 5'侧翼、外显子和内含子序列已与大肠杆菌lacZ报告基因融合，并导入小鼠种系，以鉴定调控Ets-1发育和组织特异性表达的基因组区域。Ets-1的2.4 kb 5'侧翼区域在妊娠第8.5天引导lacZ表达于胚胎折叠的神经管，这与Ets-1的内源性表达模式相同。然而，在妊娠后期，高达5.3 kb的5'侧翼区域仅导致异常表达，无法在淋巴或血管组织中赋予lacZ表达。当使用增强子捕获策略将第一个外显子和第一个内含子的9 kb与5'侧翼序列一起包含时，在发育中的血管、脑膜和脉络丛中观察到lacZ表达，这与内源性Ets-1表达相关。对内含子I中包含的血管特异性元件的进一步表征将为血管生成过程中控制基因表达的机制提供重要见解。
