Massively multiplex single-molecule oligonucleosome footprinting
- University of California San Francisco, United States
- Stanford University, United States
- Vector Institute, Canada
- Pacific Biosciences of California, Inc, United States
- University of California, San Francisco, United States
Abstract
Our understanding of the beads-on-a-string arrangement of nucleosomes has been built largely on high-resolution sequence-agnostic imaging methods and sequence-resolved bulk biochemical techniques. To bridge the divide between these approaches, we present the single-molecule adenine methylated oligonucleosome sequencing assay (SAMOSA). SAMOSA is a high-throughput single-molecule sequencing method that combines adenine methyltransferase footprinting and single-molecule real-time DNA sequencing to natively and nondestructively measure nucleosome positions on individual chromatin fibres. SAMOSA data allows unbiased classification of single-molecular 'states' of nucleosome occupancy on individual chromatin fibres. We leverage this to estimate nucleosome regularity and spacing on single chromatin fibres genome-wide, at predicted transcription factor binding motifs, and across both active and silent human epigenomic domains. Our analyses suggest that chromatin is comprised of a diverse array of both regular and irregular single-molecular oligonucleosome patterns that differ subtly in their relative abundance across epigenomic domains. This irregularity is particularly striking in constitutive heterochromatin, which has typically been viewed as a conformationally static entity. Our proof-of-concept study provides a powerful new methodology for studying nucleosome organization at a previously intractable resolution, and offers up new avenues for modeling and visualizing higher-order chromatin structure.
Data availability
All raw data will be made available at GEO Accession GSE162410; processed data is available at Zenodo (https://doi.org/10.5281/zenodo.3834705). All scripts and notebooks for reproducing analyses in the paper are available at https://github.com/RamaniLab/SAMOSA.
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Massively multiplex single-molecule oligonucleosome footprintingZenodo , zenodo.3834706.
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Massively multiplex single-molecule oligonucleosome footprintingNCBI Gene Expression Omnibus, GSE162410.
Article and author information
Author details
Funding
Sandler Foundation
- Vijay Ramani
American Cancer Society
- Laura J Hsieh
National Institutes of Health (R01GM123977)
- Hani Goodarzi
National Institutes of Health (R35GM127020)
- Geeta J Narlikar
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Job Dekker, University of Massachusetts Medical School, United States
Version history
- Received: May 28, 2020
- Accepted: November 24, 2020
- Accepted Manuscript published: December 2, 2020 (version 1)
- Version of Record published: December 14, 2020 (version 2)
Copyright
© 2020, Abdulhay et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Massively multiplex single-molecule oligonucleosome footprinting
eLife 9:e59404.
https://doi.org/10.7554/eLife.59404
Further reading
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