Kanno M, Fromental C, Staub A, Ruffenach F, Davidson I, Chambon P
Laboratorie de Génétique Moléculaire des Eucaryotes du CNRS, Unité 184 de Biologie Moléculaire et de Génie Génétique de l'INSERM, Institut de Chimie Biologique, Faculté de Médecine, Strasbourg, France.
EMBO J. 1989 Dec 20;8(13):4205-14. doi: 10.1002/j.1460-2075.1989.tb08606.x.
The enhancer activity of the oligomerized SV40 TC-I and TC-II sequences has been investigated in lymphoid and non-lymphoid cell lines. While the TC-I sequence had no demonstrable enhanson activity, a class C enhanson (proto-enhancer), 5'-GGAAAGTCCCC-3', overlapping the TC-II sequence and the GT-I enhanson was identified. This TC-II enhanson, which is identical to the kappa B motif from the kappa chain enhancer, was active in both lymphoid and non-lymphoid cells, which contrasts with the previously reported lymphoid cell specificity of the kappa B motif. However, its activity in non-lymphoid cells is in agreement with our previous reports describing the effect of mutations in the 'TC region' within the total SV40 enhancer in lymphoid and non-lymphoid cells. The activity of the TC-II enhanson could be moderately increased in HeLa by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and cycloheximide treatment, indicating that the protein(s) mediating its activity may be partially repressed by the previously described inhibitor protein I kappa B. The TC-II related, H-2Kb element, 5'-TGGGGATTCCCCA-3', of the histocompatibility class I H-2Kb gene promoter is also a class C enhanson which is active in both lymphoid and non-lymphoid cells. However, in contrast to the TC-II enhanson, the H-2Kb enhanson exhibits a very low activity in HeLa cells, but can be strongly induced by TPA and/or cycloheximide treatments which suggests that its cognate factor is inactivated (repressed) by an inhibitor protein. Interestingly, cycloheximide, but not TPA treatment, could induce the activity of both the TC-II and H-2Kb enhansons in F9 embryonal carcinoma cells, suggesting that these cells lack some component(s) of the protein kinase C signal transduction pathway. We also show that oligomers of the SV40 'core' sequence, which overlaps the TC-II enhanson, had no enhanson activity in any of the cell types studied, which questions the possible role of the AP-3 protein in SV40 enhancer activity in these cell types. In addition, oligomers of the AP-2 binding sites which are present in the SV40 TC region and in the human metallothionein IIA promoter show no enhanson activity, irrespective of whether the cells are treated with TPA.(ABSTRACT TRUNCATED AT 400 WORDS)
已在淋巴样和非淋巴样细胞系中研究了寡聚化的SV40 TC-I和TC-II序列的增强子活性。虽然TC-I序列没有可证明的增强子活性，但鉴定出了一个C类增强子（原增强子），即5'-GGAAAGTCCCC-3'，它与TC-II序列和GT-I增强子重叠。这个与κ链增强子的κB基序相同的TC-II增强子，在淋巴样和非淋巴样细胞中均有活性，这与先前报道的κB基序的淋巴样细胞特异性形成对比。然而，它在非淋巴样细胞中的活性与我们之前关于SV40总增强子中“TC区域”突变对淋巴样和非淋巴样细胞影响的报道一致。在HeLa细胞中，12-O-十四烷酰佛波醇-13-乙酸酯（TPA）和环己酰亚胺处理可适度增加TC-II增强子的活性，这表明介导其活性的蛋白质可能被先前描述的抑制蛋白IκB部分抑制。组织相容性I类H-2Kb基因启动子的与TC-II相关的H-2Kb元件，即5'-TGGGGATTCCCCA-3'，也是一个在淋巴样和非淋巴样细胞中均有活性的C类增强子。然而，与TC-II增强子不同，H-2Kb增强子在HeLa细胞中的活性非常低，但可被TPA和/或环己酰亚胺处理强烈诱导，这表明其同源因子被一种抑制蛋白失活（抑制）。有趣的是，环己酰亚胺而非TPA处理可诱导F9胚胎癌细胞中TC-II和H-2Kb增强子的活性，这表明这些细胞缺乏蛋白激酶C信号转导途径的某些成分。我们还表明，与TC-II增强子重叠的SV40“核心”序列的寡聚物在任何所研究的细胞类型中均无增强子活性，这对AP-3蛋白在这些细胞类型的SV40增强子活性中可能发挥的作用提出了质疑。此外，SV40 TC区域和人金属硫蛋白IIA启动子中存在的AP-2结合位点的寡聚物无论细胞是否用TPA处理均无增强子活性。（摘要截短于400字）
