Multivariable regulation of gene expression plasticity in metazoans

ABSTRACT An important capacity of genes is the rapid change of expression levels to cope with environment, known as expression plasticity. Elucidating the genomic mechanisms determining expression plasticity is critical for understanding the molecular basis of phenotypic plasticity, fitness, and adaptation. In this study, we systematically quantified genome-wide gene expression plasticity in four metazoan species by integrating changes of expression levels under a large number of genetic and environmental conditions. From this, we demonstrated that expression plasticity measures a distinct feature of gene expression that is orthogonal to other well-studies features including gene expression potential and tissue specificity/broadness. Expression plasticity is conserved across species with important physiological implications. The magnitude of expression plasticity is highly correlated with gene function and genes with high plasticity are implicated in disease susceptibility. Genome-wide analysis identified many conserved promoter cis -elements, trans -acting factors (such as CFCF), and gene body histone modifications (H3K36me3, H3K79me2, and H4K20me1) that are significantly associated with expression plasticity. Analysis of expression changes in perturbation experiments further validated a causal role of specific transcription factors and histone modifications. Collectively, this work reveals general properties, physiological implications, and multivariable regulation of gene expression plasticity in metazoans, extending the mechanistic understanding of gene regulation.