Molecular cloning of Drosophila HCF reveals proteolytic processing and self-association of the encoded protein.
Molecular cloning of Drosophila HCF reveals proteolytic processing and self-association of the encoded protein.
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果蝇 HCF 的分子克隆揭示了所编码蛋白质的蛋白水解加工和自关联。
DOI：
10.1002/jcp.10193
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Wilson,AngusC
中科院分区：
文献类型：
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作者：
Mahajan,ShahanaS;Johnson,KristinaM;Wilson,AngusC
HCF‐1作为单纯疱疹病毒VP16和许多哺乳动物转录因子的共激活因子。成熟的HCF‐1由两个亚基组成，这些亚基是由位于中心位置的六个HCFPROrepeats的较大前体的蛋白水解裂解产生的。由此产生的N端亚基和C端亚基通过两对互补的自关联结构域（称为SAS1N‐SAS1C和SAS2N‐SAS2C）保持紧密联系。在哺乳动物（HCF‐2）和秀丽隐杆线虫（CeHCF）中也发现了其他HCF蛋白。两者都含有保守性良好的SAS1结构域，但不经历蛋白水解加工。因此，HCF - 1的切割和自结合的意义仍然是谜。在这里，我们描述了使用基于SAS1相互作用守恒的遗传筛选对果蝇ahcf同源物（dHCF）的分离。dHCF的N端β -螺旋桨结构域支持VP16诱导的复合物形成，比其他同源物更类似于哺乳动物的HCF - 1。我们发现，在果蝇细胞中表达的全长dHCF经过蛋白水解裂解，产生紧密相关的N端和C端亚基。与HCF‐1一样，dHCF的SAS1N和SAS1C元件被一个大的中心区域分开，然而，该序列与HCF‐1切割所需的HCFPROrepeats缺乏明显的同源性。昆虫细胞中HCF加工的保守性表明，单独的N端和C端亚基的形成对HCF功能很重要。©2002 Wiley‐Liss, Inc。
HCF‐1 functions as a coactivator for herpes simplex virus VP16 and a number of mammalian transcription factors. Mature HCF‐1 is composed of two subunits generated by proteolytic cleavage of a larger precursor at six centrally‐located HCFPROrepeats. The resulting N‐ and C‐terminal subunits remain tightly associated via two complementary pairs of self‐association domains: termed SAS1N‐SAS1C and SAS2N‐SAS2C. Additional HCF proteins have been identified in mammals (HCF‐2) andCaenorhabditis elegans(CeHCF). Both contain well‐conserved SAS1 domains but do not undergo proteolytic processing. Thus, the significance of the cleavage and self‐association of HCF‐1 remains enigmatic. Here, we describe the isolation of theDrosophilaHCF homologue (dHCF) using a genetic screen based on conservation of the SAS1 interaction. The N‐terminal β‐propeller domain of dHCF supports VP16‐induced complex formation and is more similar to mammalian HCF‐1 than other homologues. We show that full‐length dHCF expressed inDrosophilacells undergoes proteolytic cleavage giving rise to tightly associated N‐ and C‐terminal subunits. As with HCF‐1, the SAS1N and SAS1C elements of dHCF are separated by a large central region, however, this sequence lacks obvious homology to the HCFPROrepeats required for HCF‐1 cleavage. The conservation of HCF processing in insect cells argues that formation of separate N‐ and C‐terminal subunits is important for HCF function. © 2002 Wiley‐Liss, Inc.