Gross I, Georgel P, Oertel-Buchheit P, Schnarr M, Reichhart J M
UPR CNRS 9022, Réponse Immunitaire et Développement chez les Insectes, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084, Strasbourg Cedex, France.
Gene. 1999 Mar 4;228(1-2):233-42. doi: 10.1016/s0378-1119(98)00595-2.
The Drosophila transcription factor Dorsal, a member of the Rel/NF-kappaB family of proteins, plays a key role in the establishment of dorsoventral polarity in the early embryo and is also involved in the immune response. Here, we present evidence that the primary transcript of dorsal can be alternatively spliced, generating Dorsal-B, a new Rel/NF-kappaB family member. Dorsal and Dorsal-B are identical in the N-terminal region, which comprises both a DNA-binding domain and a dimerization domain. However, Dorsal-B lacks the nuclear localization signal located at the end of the Rel domain of Dorsal and is totally divergent in the C-terminal portion. Although Dorsal-B by itself is not able to induce the expression of a kappaB-controlled Luciferase reporter gene, we demonstrate that its C-terminal portion has transactivating properties. Analysis of the dorsal-B expression pattern indicates that the splicing is tissue-specific and excludes a putative role in early embryogenesis. However, dorsal-B synthesis is enhanced upon septic injury, and this challenge induces a nuclear accumulation of the protein in fat body cells suggesting that it may be involved in the immune response.
果蝇转录因子背腹蛋白（Dorsal）是Rel/NF-κB蛋白家族的成员之一，在早期胚胎背腹极性的建立过程中发挥关键作用，并且也参与免疫反应。在此，我们提供证据表明，背腹蛋白的初级转录本可以进行可变剪接，产生一种新的Rel/NF-κB家族成员背腹蛋白B（Dorsal-B）。背腹蛋白和背腹蛋白B在N端区域相同，该区域同时包含一个DNA结合结构域和一个二聚化结构域。然而，背腹蛋白B缺乏位于背腹蛋白Rel结构域末端的核定位信号，并且在C端部分完全不同。尽管背腹蛋白B自身不能诱导κB调控的荧光素酶报告基因的表达，但我们证明其C端部分具有反式激活特性。对背腹蛋白B表达模式的分析表明，这种剪接是组织特异性的，并且排除了其在早期胚胎发生中的假定作用。然而，在脓毒症损伤后，背腹蛋白B的合成增强，并且这种刺激诱导该蛋白在脂肪体细胞中发生核积累，表明它可能参与免疫反应。
