Comparison of Hi-C results using in-solution versus in-nucleus ligation

Takashi Nagano, Csilla Várnai, Stefan Schoenfelder, Biola M Javierre, Steven W Wingett, Peter Fraser

Research output: Contribution to journalArticlepeer-review

96 Citations (Scopus)
32 Downloads (Pure)

Abstract

Background
Chromosome conformation capture and various derivative methods such as 4C, 5C and Hi-C have emerged as standard tools to analyze the three-dimensional organization of the genome in the nucleus. These methods employ ligation of diluted cross-linked chromatin complexes, intended to favor proximity-dependent, intra-complex ligation. During development of single-cell Hi-C, we devised an alternative Hi-C protocol with ligation in preserved nuclei rather than in solution. Here we directly compare Hi-C methods employing in-nucleus ligation with the standard in-solution ligation.

Results
We show in-nucleus ligation results in consistently lower levels of inter-chromosomal contacts. Through chromatin mixing experiments we show that a significantly large fraction of inter-chromosomal contacts are the result of spurious ligation events formed during in-solution ligation. In-nucleus ligation significantly reduces this source of experimental noise, and results in improved reproducibility between replicates. We also find that in-nucleus ligation eliminates restriction fragment length bias found with in-solution ligation. These improvements result in greater reproducibility of long-range intra-chromosomal and inter-chromosomal contacts, as well as enhanced detection of structural features such as topologically associated domain boundaries.

Conclusions
We conclude that in-nucleus ligation captures chromatin interactions more consistently over a wider range of distances, and significantly reduces both experimental noise and bias. In-nucleus ligation creates higher quality Hi-C libraries while simplifying the experimental procedure. We suggest that the entire range of 3C applications are likely to show similar benefits from in-nucleus ligation.
Original languageEnglish
Article number175
Number of pages13
JournalGenome Biology
Volume16
DOIs
Publication statusPublished - 26 Aug 2015

Keywords

  • Genomic Distance
  • Technical Noise
  • Chromosome Conformation Capture
  • Mouse Foetal Liver
  • Interaction Count

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