van Duin, L. | Search bioRxiv

bioRxiv2022

Transcription factor expression is the main determinant of variability in gene co-activity

Many genes are co-expressed and form genomic domains of coordinated gene activity. However, the regulatory determinants of domain co-activity remain unclear. Here, we leverage human individual variation in gene expression to characterize the co-regulatory processes underlying domain co-activity and systematically quantify their effect sizes. We employ transcriptional decomposition to extract from RNA expression data an expression component related to co-activity revealed by genomic positioning. This strategy reveals close to 1,500 co-activity domains, covering most expressed genes, of which the large majority are invariable across individuals. Focusing specifically on domains with high variability in co-activity reveals that contained genes have a higher sharing of eQTLs, a higher variability in enhancer interactions, and an enrichment of binding by variably expressed transcription factors compared to genes within non-variable domains. Through careful quantification of the relative contributions of regulatory processes underlying co-activity, we find transcription factor expression levels to be the main determinant of gene co-activity. Our results indicate that distal trans effects contribute more than local genetic variation to individual variation in co-activity domains.

bioinformatics↗

bioRxiv2017

Transcriptional decomposition reveals active chromatin architectures and cell specific regulatory interactions

Transcriptional regulation is tightly coupled with chromosomal positioning and three-dimensional chromatin architecture. However, it is unclear what proportion of transcriptional activity is reflecting such organisation, how much can be informed by RNA expression alone, and how this impacts disease. Here, we develop a transcriptional decomposition approach separating the proportion of expression associated with genome organisation from independent effects not directly related to genomic positioning.\n\nWe show that positionally attributable expression accounts for a considerable proportion of total levels and is highly informative of topological associating domain activities and organisation, revealing boundaries and chromatin compartments. Furthermore, expression data alone accurately predicts individual enhancer-promoter interactions, drawing features from expression strength, stabilities, insulation and distance. We further characterise commonalities and differences across predictions in 76 human cell types, observing extensive sharing of domains, yet highly cell-type specific enhancer-promoter interactions and strong enrichments in relevant trait-associated variants. Our work demonstrates a close relationship between transcription and chromatin architecture, presenting a novel strategy and an unprecedented resource for investigating regulatory organisations and interpretations of disease associated genetic variants across cell types.

genomics↗