Genomic encoding of transcriptional burst kinetics

We sequenced allele-resolution single-cell transcriptomes from mouse primary fibroblasts and embryonic stem cells with the overall aim to infer transcriptional kinetics for each gene and allele. Inferred transcriptional burst kinetics revealed the genomic encoding of transcriptional burst frequencies and sizes within the genome. Core promoter elements were found to specify burst sizes, whereas burst frequencies were regulated by enhancers. In particular burst frequencies were found to account for cell-type differences in gene expression levels and were also mostly correlating with absolute expression levels in cells. Importantly, the patterns identified were not detectable at the level of mean expression demonstrating the need to investigate transcriptional dynamics at the level of burst kinetics.