Systematic alteration of ATAC-seq for profiling open chromatin in cryopreserved nuclei preparations from livestock tissues

Sci Rep. 2020 Mar 23;10(1):5230. doi: 10.1038/s41598-020-61678-9.

Abstract

The use of Assay for Transposase-Accessible Chromatin (ATAC-seq) to profile chromatin accessibility has surged over the past years, but its applicability to tissues has been very limited. With the intent of preserving nuclear architecture during long-term storage, cryopreserved nuclei preparations from chicken lung were used to optimize ATAC-seq. Sequencing data were compared with existing DNase-seq, ChIP-seq, and RNA-seq data to evaluate library quality, ultimately resulting in a modified ATAC-seq method capable of generating high quality chromatin accessibility data from cryopreserved nuclei preparations. Using this method, nucleosome-free regions (NFR) identified in chicken lung overlapped half of DNase-I hypersensitive sites, coincided with active histone modifications, and specifically marked actively expressed genes. Notably, sequencing only the subnucleosomal fraction dramatically improved signal, while separation of subnucleosomal reads post-sequencing did not improve signal or peak calling. The broader applicability of this modified ATAC-seq technique was tested using cryopreserved nuclei preparations from pig tissues, resulting in NFR that were highly consistent among biological replicates. Furthermore, tissue-specific NFR were enriched for binding motifs of transcription factors related to tissue-specific functions, and marked genes functionally enriched for tissue-specific processes. Overall, these results provide insights into the optimization of ATAC-seq and a platform for profiling open chromatin in animal tissues.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cell Nucleus / genetics*
  • Chickens
  • Chromatin / metabolism*
  • Chromatin Immunoprecipitation Sequencing / methods*
  • Cryopreservation / methods*
  • DNA, Intergenic
  • Deoxyribonuclease I / metabolism
  • High-Throughput Nucleotide Sequencing / methods
  • Livestock
  • Lung / cytology
  • Male
  • Muscle, Skeletal / cytology
  • Promoter Regions, Genetic
  • Spleen / cytology
  • Swine

Substances

  • Chromatin
  • DNA, Intergenic
  • Deoxyribonuclease I