White E K, Moore-Jarrett T, Ruley H E
Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2363, USA.
RNA. 2001 Dec;7(12):1855-66.
Members of the Puf family of RNA-binding proteins from Drosophila, Caenorhabditis elegans, and Dictyostelium are known to function as translational repressors. To identify mammalian proteins that might regulate posttranscriptional gene expression, we have characterized a novel murine Puf protein, PUM2. Pum2 transcripts were expressed in all murine tissues examined, suggesting the gene influences processes common to many cell types. Like all Puf family members, PUM2 contains a C-terminal RNA-binding domain related to the Drosophila Pumilio homology domain (PUM-HD). Two features found in the amino-terminus of PUM2, regions rich in serine and glutamine/alanine-rich regions, were also identified in most Puf family members. RNA sequences capable of binding with high affinity (6.5 nM) to a 48-kDa recombinant protein containing the PUM2 PUM-HD were isolated by using an iterative amplification-selection protocol (SELEX). The consensus sequence [UGUANAUARNNNNBBBBSCCS] of the PUM2 binding element (PBE) is related to, but distinct from, the 3' end of the Drosophila Nanos response element. The characterization of PUM2 and potential RNA-binding site will assist efforts to assess the extent and mechanism by which mammalian genes are regulated at a posttranscriptional level.
已知来自果蝇、秀丽隐杆线虫和盘基网柄菌的RNA结合蛋白Puf家族成员可作为翻译抑制因子发挥作用。为了鉴定可能调节转录后基因表达的哺乳动物蛋白，我们对一种新型小鼠Puf蛋白PUM2进行了表征。Pum2转录本在所有检测的小鼠组织中均有表达，这表明该基因影响许多细胞类型共有的过程。与所有Puf家族成员一样，PUM2含有一个与果蝇Pumilio同源结构域（PUM-HD）相关的C端RNA结合结构域。在PUM2的氨基末端发现的两个特征，即富含丝氨酸的区域和富含谷氨酰胺/丙氨酸的区域，在大多数Puf家族成员中也有发现。通过使用迭代扩增-选择方案（SELEX），分离出了能够与含有PUM2 PUM-HD的48 kDa重组蛋白以高亲和力（6.5 nM）结合的RNA序列。PUM2结合元件（PBE）的共有序列[UGUANAUARNNNNBBBBSCCS]与果蝇Nanos反应元件的3'端相关，但又有所不同。PUM2和潜在RNA结合位点的表征将有助于评估哺乳动物基因在转录后水平上受到调控的程度和机制。
