Garay-Rojas E, Harper M, Hraba-Renevey S, Kress M
UPR9044-CNRS, IRC, Villejuif, France.
Gene. 1996 May 8;170(2):173-80. doi: 10.1016/0378-1119(95)00896-9.
We have isolated, sequenced and characterized the mouse 24p3 gene. The 24p3 protein is a member of the lipocalin family comprising secreted transporters of hydrophobic ligands. The 24p3 cDNA had been initially isolated during a search for genes overexpressed during a SV40-induced mitotic reaction [Hraba-Renevey et al., Oncogene 4 (1989) 601-608]. 24p3 comprises six exons, five introns and 793 bp of 5' regulatory region. The transcription start point (tsp) was identified by primer extension. Putative regulatory elements, including a TATA-like box and two glucocorticoid responsive core elements (GRE), have been mapped in the 5'-flanking region. Based on this observation, we examined the effect of a glucocorticoid (dexamethasone, Dex) on 24p3 expression. Dex induced the expression of 24p3 dramatically in the absence of de novo protein synthesis. This activation was further amplified by an apparent autocrine mechanism. Similar results were obtained with retinoic acid. Using the cat reporter gene system, we have shown that the 5'-flanking region of 24p3 confers Dex inducibility. Furthermore, we have identified a 43-bp region of the 24p3 promoter required for the Dex responsiveness. The biological implications are discussed in light of these results.
我们已经分离、测序并鉴定了小鼠24p3基因。24p3蛋白是脂质运载蛋白家族的成员，该家族包含疏水性配体的分泌转运蛋白。24p3 cDNA最初是在寻找SV40诱导的有丝分裂反应中过表达的基因时分离得到的[Hraba-Renevey等人，《癌基因》4 (1989) 601 - 608]。24p3包含六个外显子、五个内含子和793 bp的5'调控区。通过引物延伸确定了转录起始点（tsp）。在5'侧翼区域已定位了推定的调控元件，包括一个类TATA盒和两个糖皮质激素反应核心元件（GRE）。基于这一观察结果，我们研究了糖皮质激素（地塞米松，Dex）对24p3表达的影响。在没有从头合成蛋白质的情况下，Dex显著诱导了24p3的表达。这种激活通过一种明显的自分泌机制进一步放大。视黄酸也得到了类似的结果。使用氯霉素乙酰转移酶（cat）报告基因系统，我们已经证明24p3的5'侧翼区域赋予了Dex诱导性。此外，我们已经确定了24p3启动子中一个43 bp的区域，该区域是Dex反应性所必需的。根据这些结果讨论了其生物学意义。
