Project description:We built and tested a library of 10,898 σ70 promoter variants consisting of all combinations of a set of eight -35 elements, eight -10 elements, three UP elements, eight spacers, and eight backgrounds. Using a Massively Parallel Reporter Assay, we measure expression of all promoters and evaluate how individual promoter elements contribute to expression.
Project description:We designed and assayed synthetic regulatory elements varying c-amp response element number, affinity, distance to the promoter, spacing between multiple CREs, and surrounding sequence content. Using 5 massively-parallel reporter assays, we measured the expression of 17,406 unique sequences when placed upstream of a minimal promoter using next-generation sequencing of barcodes associated with synthesized elements. We then determine how the varied c-amp response element architectures influence expression when these variants are assayed in an episomal and genomic context across a range of forskolin concentrations, an inducer of c-amp response element activity. Included here are all sequences designed and analyzed in the assay. Assay results from certain library designs were not insightful and not included in the main text but are additionally included here in the barcode-mapping and MPRA sequencing datasets.
Project description:We used 2 massively parallel reporter assays to characterize 5,706 unique noncoding genetic variants derived from genome-wide association studies for two neurodegenerative disorders: Alzheimer’s disease (AD) and Progressive Supranuclear Palsy (PSP). Specifically, we synthesized a library consisting of both alleles of each SNV embedded within their native genomic context, which was cloned upstream of a minimal promoter within an expression vector. We then measured the transcriptional drive of each library element using next-generation sequencing of barcoded transcripts uniquely associated with each regulatory element. This enabled the identification of variants with significant transcriptional skew between alleles representing likely functional regulatory variants underlying disease risk.
Project description:An alternative sigma factor (σ32) recognizes the unique set of promoters upon heat shock. Here, we determined 54 σ32 promoters at nucleotide resolution using ChIP-exo, enabling us to compare those with housekeeping σ70 promoters. The results elucidated the overarching principles of promoter overlapping between the two σ-factors, which are sequence-specific non-, half-, and full-shared modes with a perfect sequence conservativeness of −35 element as a key determinant of full-shared mode.
Project description:An alternative sigma factor (σ32) recognizes the unique set of promoters upon heat shock. Here, we determined 54 σ32 promoters at nucleotide resolution using ChIP-exo, enabling us to compare those with housekeeping σ70 promoters. The results elucidated the overarching principles of promoter overlapping between the two σ-factors, which are sequence-specific non-, half-, and full-shared modes with a perfect sequence conservativeness of −35 element as a key determinant of full-shared mode.
Project description:Substrains in Escherichia coli K-12 MG1655 can possess various swimming motility, which is mostly resulted from different expression levels of flhDC. Here, we studied the swimming motility of two MG1655 substrains, CY562 and CY570. Our results showed that CY562 had no insertion at the promoter region of flhDC and possessed no swimming motility. In contrast, CY570 had an IS-element insertion at the promoter region of flhDC and showed a hyper-motile phenotype. Transcriptomic data suggest that expression of flhDC and the other known flagella genes was much lower in CY562 than that in CY570. Moreover, CY562 possessed higher expression levels for genes involved in stress response, especially acid-stress response, than CY570. Consistently, CY562 showed a higher survival rate under acid stress than CY570. Our data indicate that there are mechanisms conversely regulating motility and stress response in E. coli.
