NLM IRP Seminar Schedule
UPCOMING SEMINARS
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May 14, 2024 Stanley Liang
Knowledge-driven Latent Diffusion For COVID-19 Pneumonia Radiology Pattern Synthesis -
May 21, 2024 Ziynet Kesimoglu
TBD -
May 23, 2024 Leslie Ronish
TBD -
May 28, 2024 Harutyun Saakyan
TBD -
May 30, 2024 Deepak Gupta
TBD
RECENT SEMINARS
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May 9, 2024 Pascal Mutz
The Riboviria protein structurome expands virus protein annotation and highlights protein relations -
May 2, 2024 OPEN
TBD -
April 30, 2024 Wenya Rowe
The conformal central charge of the spin-1/2 XX model derived from long-chain asymptotics -
April 25, 2024 Ermin Hodzic
Condition-Aware Cell Type Deconvolution of Bulk Tissues -
April 16, 2024 Jaya Srivastava
Regulatory plasticity of the human genome
Scheduled Seminars on Feb. 9, 2023
Contact NLM_IRP_Seminar_Scheduling@mail.nih.gov with questions about this seminar.
Abstract:
Millions of enhancers have been predicted in the human and mouse genomes based on enhancer-like signatures or massively parallel report assays (MPRAs). The number of experimentally validated in vivo enhancer-promoter pairs is, however, only in the dozens. How exactly tens of thousands of enhancers and active promoters in a cell organize into transcription regulatory loops remains unclear.
Using TF enrichment as an indicator of enhancer strength, we identified a portion of H3K27ac peaks as potentially strong enhancers and found a universal pattern of promoter and enhancer distribution that would not show if all the H3K27ac peaks are counted as enhancers: At actively transcribed regions of length of ~200-300kb, the numbers of active promoters and enhancers are inversely related. Super enhancers or enhancer clusters are associated with isolated active promoters, regardless of the gene’s cell-type specificity. As the number of nearby active promoters increases, the number of enhancers decreases. At regions where multiple active genes are closely located, there are few distant enhancers. With Hi-C analysis, we demonstrate that the interactions among the regulatory elements occur predominantly in clusters and multiway among linearly close elements . We propose a simple model of spatial organization of active promoters and enhancers: Gene transcriptions and regulations mainly occur at local active transcription hubs contributed dynamically by multiple elements from linearly close enhancers and/or active promoters. The model can be represented with a flower-shaped structure. Furthermore, local transcription hubs from distant parts of a chromosome can get into contact and form larger hubs, reflected as nodes in hierarchical TAD structures in Hi-C contact maps.