Protein abundance differs from a few to millions of copies per cell. Trypanosoma brucei presents an excellent model for studies on codon bias and differential gene expression because transcription is broadly unregulated and uniform across the genome. T. brucei is also a major human and animal protozoal pathogen. Here, an experimental assessment, using synthetic reporter genes, revealed that GC3 codons have a major positive impact on both mRNA and protein abundance. Our estimates of relative expression, based on coding sequences alone (codon usage and sequence length), are within 2-fold of the observed values for the majority of measured cellular mRNAs (n > 7000) and proteins (n > 2000). Our estimates also correspond with expression measures from published transcriptome and proteome datasets from other trypanosomatids. We conclude that codon usage is a key factor affecting global relative mRNA and protein expression in trypanosomatids and that relative abundance can be effectively estimated using only protein coding sequences.

中文翻译：

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密码子使用偏差控制锥虫中的 mRNA 和蛋白质丰度

每个细胞的蛋白质丰度从几到几百万个不等。Trypanosoma brucei 为密码子偏倚和差异基因表达的研究提供了一个极好的模型，因为转录在整个基因组中是广泛不受管制和统一的。T. brucei 也是一种主要的人类和动物原生动物病原体。在这里，使用合成报告基因的实验评估表明，GC3 密码子对 mRNA 和蛋白质丰度都有重大的积极影响。我们对相对表达的估计，仅基于编码序列（密码子使用和序列长度），在大多数测量的细胞 mRNA（n > 7000）和蛋白质（n > 2000）的观察值的 2 倍以内。我们的估计也对应于来自其他锥虫的已发表转录组和蛋白质组数据集的表达测量。