Post-transcriptional mechanisms modulate the consequences of adaptive copy number variation

Copy-number variants (CNVs) are large-scale amplifications or deletions of DNA that can drive rapid adaptive evolution and result in large-scale changes in gene expression. Whereas alterations in the copy number of one or more genes within a CNV can confer a selective advantage, other genes within a CNV can decrease fitness when their dosage is changed. Dosage compensation - in which the gene expression output from multiple gene copies is less than expected - is one means by which an organism can mitigate the fitness costs of deleterious gene amplification. Previous research has shown evidence for dosage compensation at both the transcriptional level and at the level of protein expression; however, the extent of compensation differs substantially between genes, strains, and studies. Here, we investigated sources of dosage compensation at multiple levels of gene expression regulation by defining the transcriptome, translatome and proteome of experimentally evolved yeast (Saccharomyces cerevisiae) strains containing adaptive CNVs.

拷贝数变异（Copy-number variants, CNVs）是可驱动快速适应性进化、并引发基因表达大规模改变的DNA大规模扩增或缺失变异。尽管CNV内单个或多个基因的拷贝数改变可赋予选择优势，但CNV内其他基因的剂量发生变化时会降低个体适合度。剂量补偿（dosage compensation）——即多基因拷贝的基因表达产出低于预期水平——是生物体缓解有害基因扩增带来的适合度代价的一种途径。既往研究已在转录水平与蛋白质表达水平上发现了剂量补偿的证据；不过补偿程度在不同基因、菌株与研究间存在显著差异。本研究通过对携带适应性CNV的实验进化酿酒酵母（Saccharomyces cerevisiae）菌株的转录组、翻译组与蛋白质组进行解析，探究了基因表达调控多层面下的剂量补偿来源。