Duarte R, Stein L, Fabian B, Segev O
UNIV WITWATERSRAND, DEPT ZOOL, WITWATERSRAND 2050, SOUTH AFRICA.
Int J Oncol. 1995 Nov;7(5):1203-12. doi: 10.3892/ijo.7.5.1203.
Chloramphenicol acetyl transferase reporter plasmids driven by the Drosophila ras2/rop promoter were injected into Xenopus oocytes to study Dras2 and rop gene regulation by their bidirectional promoter. When injected without Drosophila nuclear extract, both Dras2 and rep were highly expressed. Dras2 and rop-CAT expression was very similar in Drosophila cells and Xenopus oocytes, suggesting the conservation of regulatory factors between the two species. When Drosophila nuclear extract was co-injected with Dras2 and rep promoter-CAT constructs, expression was inhibited. Inhibition decreased with elevation of plasmid concentration and was increased with an increase in nuclear extract concentration. Since specific DNA-protein interactions were diminished by the combination of oocyte and Drosophila nuclear extracts in gel retardation assays, a sequestering-type mechanism of repression has been proposed.
将由果蝇ras2/rop启动子驱动的氯霉素乙酰转移酶报告质粒注射到非洲爪蟾卵母细胞中，以研究Dras2和rop基因受其双向启动子的调控情况。在不注射果蝇核提取物的情况下进行注射时，Dras2和rep均高度表达。Dras2和rop-CAT在果蝇细胞和非洲爪蟾卵母细胞中的表达非常相似，这表明这两个物种之间调控因子具有保守性。当将果蝇核提取物与Dras2和rep启动子-CAT构建体共同注射时，表达受到抑制。抑制作用随质粒浓度升高而降低，随核提取物浓度增加而增强。由于在凝胶阻滞试验中，卵母细胞和果蝇核提取物的组合减少了特异性DNA-蛋白质相互作用，因此提出了一种螯合型抑制机制。
