RNA. 2010 Jul;16(7):1293-300. doi: 10.1261/rna.2109710. Epub 2010 May 19.
Small nucleolar RNAs (snoRNAs) guide nucleotide modifications within ribosomal RNAs or spliceosomal RNAs by base-pairing to complementary regions within their RNA targets. The brain-specific snoRNA MBII-52 lacks such a complementarity to rRNAs or snRNAs, but instead has been reported to target the serotonin receptor 2C pre-mRNA, thereby regulating pre-mRNA editing and/or alternative splicing. To understand how the MBII-52 snoRNA might be involved in these regulatory processes, we isolated the MBII-52 snoRNP from total mouse brain by an antisense RNA affinity purification approach. Surprisingly, by mass spectrometry we identified 17 novel candidates for MBII-52 snoRNA binding proteins, which previously had not been reported to be associated with canonical snoRNAs. Among these, Nucleolin and ELAVL1 proteins were confirmed to independently and directly interact with the MBII-52 snoRNA by coimmunoprecipitation. Our findings suggest that the MBII-52 snoRNA assembles into novel RNA-protein complexes, distinct from canonical snoRNPs.
小核仁 RNA（snoRNAs）通过与 RNA 靶标中互补区域的碱基配对，指导核糖体 RNA 或剪接体 RNA 内的核苷酸修饰。脑特异性 snoRNA MBII-52 与 rRNA 或 snRNA 没有这种互补性，但据报道它可以靶向 5-羟色胺受体 2C 前体 mRNA，从而调节前体 mRNA 的编辑和/或选择性剪接。为了了解 MBII-52 snoRNA 如何参与这些调控过程，我们通过反义 RNA 亲和纯化方法从总鼠脑中分离出 MBII-52 snoRNP。令人惊讶的是，通过质谱分析，我们鉴定出 17 种新的 MBII-52 snoRNA 结合蛋白候选物，这些蛋白以前没有被报道与典型 snoRNA 相关。其中，核仁蛋白和 ELAVL1 蛋白通过共免疫沉淀被证实可独立且直接与 MBII-52 snoRNA 相互作用。我们的研究结果表明，MBII-52 snoRNA 组装成新型的 RNA-蛋白质复合物，与典型 snoRNPs 不同。
