Regulation of protein synthesis is an essential step of gene expression. This process is under the control of cis-acting RNA elements and trans-acting factors. Gemin5 is a multifunctional RNA-binding protein organized in distinct domains. The protein bears a non-canonical RNA-binding site, designated RBS1, at the C-terminal end. Among other cellular RNAs, the RBS1 region recognizes a sequence located within the coding region of Gemin5 mRNA, termed H12. Expression of RBS1 stimulates translation of RNA reporters carrying the H12 sequence, counteracting the negative effect of Gemin5 on global protein synthesis. A computational analysis of RBS1 protein and H12 RNA variability across the evolutionary scale predicts coevolving pairs of amino acids and nucleotides. RBS1 footprint and gel-shift assays indicated a positive correlation between the identified coevolving pairs and RNA-protein interaction. The coevolving residues of RBS1 contribute to the recognition of stem-loop SL1, an RNA structural element of H12 that contains the coevolving nucleotides. Indeed, RBS1 proteins carrying substitutions on the coevolving residues P₁₂₉₇ or S₁₂₉₉S₁₃₀₀, drastically reduced SL1-binding. Unlike the wild type RBS1 protein, expression of these mutant proteins in cells failed to enhance translation stimulation of mRNA reporters carrying the H12 sequence. Therefore, the PXSS motif within the RBS1 domain of Gemin5 and the RNA structural motif SL1 of its mRNA appears to play a key role in fine-tuning the expression level of this essential protein.

蛋白质合成的调控是基因表达的重要步骤。该过程在顺式作用RNA元件和反式作用因子的控制下。Gemin5是在不同域中组织的多功能RNA结合蛋白。该蛋白质在C末端带有一个非典型的RNA结合位点，称为RBS1。在其他细胞RNA中，RBS1区识别位于Gemin5 mRNA编码区内的序列，称为H12。RBS1的表达刺激带有H12序列的RNA报告基因的翻译，抵消了Gemin5对整体蛋白质合成的负面影响。RBS1蛋白和H12 RNA在整个进化规模上的变异性的计算分析预测了氨基酸和核苷酸的共同进化。RBS1足迹和凝胶位移分析表明已鉴定的进化对与RNA-蛋白质相互作用之间呈正相关。RBS1的共同进化残基有助于识别茎环SL1，SL1是H12的RNA结构元件，其中含有共同进化的核苷酸。确实，RBS1蛋白在共同进化的残基P上带有取代基₁₂₉₇或S ₁₂₉₉ S ₁₃₀₀，大大降低了SL1结合。与野生型RBS1蛋白不同，这些突变蛋白在细胞中的表达未能增强带有H12序列的mRNA报告基因的翻译刺激。因此，Gemin5的RBS1域内的PXSS基序及其mRNA的RNA结构基序SL1似乎在微调该必需蛋白的表达水平中起着关键作用。