Dissecting the contributions of GC content and codon usage to gene expression in the model alga Chlamydomonas reinhardtii.
Dissecting the contributions of GC content and codon usage to gene expression in the model alga Chlamydomonas reinhardtii.
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DOI：
10.1111/tpj.13033
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发表时间：
2015-11
期刊：
影响因子：
--
通讯作者：
Bock R
中科院分区：
文献类型：
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作者：
Barahimipour R;Strenkert D;Neupert J;Schroda M;Merchant SS;Bock R
所有生物体中基因表达的效率取决于编码区的核苷酸组成。GC含量和密码子使用是已知影响基因表达的两个关键序列特征，但潜在的分子机制并不完全清楚。在这里，我们已经确定了GC含量和密码子使用的相对贡献核基因表达的效率在单细胞绿色衣藻莱茵衣藻。通过比较编码相同氨基酸序列但GC含量和/或密码子使用不同的基因变体，我们表明密码子使用是决定翻译效率的关键因素，令人惊讶的是，也是mRNA稳定性的关键因素。相反，不利的GC含量通过触发异染色质化在染色质结构水平上影响基因表达。我们进一步表明，允许高水平转基因表达的突变藻株对表观遗传转基因抑制不太敏感，并且在转基因位点不建立抑制性染色质结构。我们的数据解开了GC含量和密码子使用之间的关系，并提出了克服衣藻中转基因表达问题的简单策略。
The efficiency of gene expression in all organisms depends on the nucleotide composition of the coding region. GC content and codon usage are the two key sequence features known to influence gene expression, but the underlying molecular mechanisms are not entirely clear. Here we have determined the relative contributions of GC content and codon usage to the efficiency of nuclear gene expression in the unicellular green alga Chlamydomonas reinhardtii. By comparing gene variants that encode an identical amino acid sequence but differ in their GC content and/or codon usage, we show that codon usage is the key factor determining translational efficiency and, surprisingly, also mRNA stability. By contrast, unfavorable GC content affects gene expression at the level of the chromatin structure by triggering heterochromatinization. We further show that mutant algal strains that permit high-level transgene expression are less susceptible to epigenetic transgene suppression and do not establish a repressive chromatin structure at the transgenic locus. Our data disentangle the relationship between GC content and codon usage, and suggest simple strategies to overcome the transgene expression problem in Chlamydomonas.