Oliveira Camila, Carvalho Paulo Costa, Alves Lysangela Ronalte, Goldenberg Samuel
Instituto Carlos Chagas, Fiocruz-Paraná, Rua Professor Algacyr Munhoz Mader, 3775, Cidade Industrial de Curitiba-CIC, 81350-010, Curitiba, Brasil.
PLoS One. 2016 Oct 19;11(10):e0164650. doi: 10.1371/journal.pone.0164650. eCollection 2016.
The regulation of gene expression in trypanosomatids occurs mainly at the post-transcriptional level. Despite the importance of this type of control in Trypanosoma cruzi, few RNA binding proteins have been characterized. The RRM domain (RNA Recognition Motif) is one of the most abundant domains found in RNA-binding proteins in higher eukaryotes. Proteins containing the RRM domain are involved in the majority of post-transcriptional processes regulating gene expression. In this work, we aimed to characterize the protein TcNRBD1 from T. cruzi. TcNRBD1 is an RNA-binding protein that contains 2 RRM domains and is the ortholog of the P34 and P37 proteins from Trypanosoma brucei. The TcNRBD1 protein is expressed in all developmental stages of T. cruzi, and its localization pattern is concentrated at the perinuclear region. TcNRBD1 is associated with polysomes and with the 80S monosomes. Furthermore, sequencing of the mRNAs bound to TcNRBD1 allowed the identification of several transcripts that encode ribosomal proteins. Immunoprecipitation assays followed by mass spectrometry showed that the protein complexes with several ribosomal proteins from both the 40S and 60S subunits. In summary, the results indicate that TcNRBD1 is associated with different parts of the translation process, either by regulating mRNAs that encode ribosomal proteins or by acting in some step of ribosome assembly in T. cruzi.
锥虫中的基因表达调控主要发生在转录后水平。尽管这种调控类型在克氏锥虫中很重要，但已鉴定的RNA结合蛋白却很少。RRM结构域（RNA识别基序）是高等真核生物RNA结合蛋白中最丰富的结构域之一。含有RRM结构域的蛋白质参与了大多数调控基因表达的转录后过程。在这项工作中，我们旨在鉴定克氏锥虫中的蛋白质TcNRBD1。TcNRBD1是一种RNA结合蛋白，含有2个RRM结构域，是布氏锥虫P34和P37蛋白的直系同源物。TcNRBD1蛋白在克氏锥虫的所有发育阶段均有表达，其定位模式集中在核周区域。TcNRBD1与多核糖体和80S单核糖体相关。此外，对与TcNRBD1结合的mRNA进行测序，鉴定出了几种编码核糖体蛋白的转录本。免疫沉淀分析及随后的质谱分析表明，该蛋白与40S和60S亚基的几种核糖体蛋白形成复合物。总之，结果表明TcNRBD1通过调控编码核糖体蛋白的mRNA或在克氏锥虫核糖体组装的某些步骤中发挥作用，与翻译过程的不同部分相关。
