3dgenome
  • Initial page
  • Cover
  • Preface
  • Figurelist
  • Chap0 Preparation
    • 0.1 Molecular biology
    • 0.2 Sequencing technologies
    • 0.3 RNA-seq Data Mapping & Gene Quantification
    • 0.4 RNA-seq Differential Analysis
  • Chap1 Why we care about 3D genome
    • 1.1 From 2D to 3D nuclear structure
    • 1.2 From static to dynamic
    • 1.3 From intra to inter chromosomes "talk"
    • 1.4 From aggregation to division - phase separation
  • Chap2 experiment tools for exploring genome interaction
    • 2.1 Image based
    • 2.2 Primary order
    • 2.3 Higher order C-techs
  • Chap3 Computational analysis
    • 3.1 Primary order analysis
    • 3.2 Higer order data analysis
      • 3.2.1 Read mapping consideration
      • 3.2.2 Analytical Pipelines
        • GITAR Pipeline
        • HiC-Pro Pipeline
      • 3.2.3 TAD calling algorithms
    • 3.3 3D structure
  • Chap4 RNA-genome interaction
    • 4.1 Experimental Methods
    • 4.2 Computational Analysis
  • Chap5 Integrative Data Visualization Tools
    • 5.1 GIVE
    • 5.2 HiGlass
  • Chap6 4DN Project
  • Appendix
    • Homework
    • Student's presentation
      • A Brief Introduction to Machine Learning
      • Precision medicine
      • CHIP-Seq
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  • C-Techs (chromosome conformation capture)-coupled
  • 2.3.1 Introduction
  • 2.3.2 Overivew of 3C methods
  • 2.3.3 Hi-C
  • 2.3.4 ChIA-PET
  • 2.3.5 Selected methods comparison
  1. Chap2 experiment tools for exploring genome interaction

2.3 Higher order C-techs

C-Techs (chromosome conformation capture)-coupled

  1. Introduction

  2. Overview of 3C-based methods

    2.1. Specificity

    2.2. Through-put and resolution

  3. Hi-C

  4. ChIA-PET

  5. Selected methods comparison

2.3.1 Introduction

The foundamental object of 3C(Chromosome Conformation Capture) techniques and 3C-derived methods is to understand the physical wiring diagram of the genome by identifying the physical interaction between chromosomes.

To capture the interaction (crosslink between strings), there are few steps in general:

  • Take a snapshot of the flowing cells - Crosslink with fixative agent (formaldehyde)

  • Zoom in on crosslinked part and exclude untangled parts - Digested with a restriction enzyme

  • Analyze the components come from the same chromatin - Reverse crosslink and sequence

  • Finish the jigsaw puzzle and get the results - Align the reads and summarize the contacts

Based on these general ideas, then we'll dive deeper by walking through two of the most popular techniques and then briefly introduce some other methods.

2.3.2 Overivew of 3C methods

To better understand the difference between these methods, I'd like to distinguish them between the following couple of aspects:

1) Specificity - What does one, all, many mean

These kind of specificity is determined by the primer when people use specific primers before PCR.

2) Through-put and resolution

2.3.3 Hi-C

Hi-C is the highest through-put version of 3C-derived technologies. Due to the decreasing cost of 2nd generation sequencing, Hi-C is widely used.

The principle of Hi-C can be illustrated as:

  • Fixation: keep DNA conformed

  • Digestion: enzyme frequency and penetration

  • Fill-in: biotin for junction enrichment

  • Ligation: freeze interactions in sequence

  • Biotin removal: junctions only

  • Fragment size: small fragments sequence better

  • Adapter ligation: paired-end and indexing

  • PCR: create enough material for flow cell

Hi-C derived techniques

2.3.4 ChIA-PET

ChIA-PET is another method that combines ChIP and pair-end sequencing to analysis the chromatin interaction. It allows for targeted binding factors such as: estrogen receptor alpha, CTCF-mediated loops, RNA polymerase II, and a combination of key architectural factors. On the one hand, it has the benefit of achieving a higher resolution compared to Hi-C, as only ligation products involving the immunoprecipitated molecule are sequenced, on the other hand, ChIA-PET has systematic biases due to ChIP process:

  • Only one type of binding factor selected

  • Different antibodies

  • ChIP conditions

2.3.5 Selected methods comparison

Method

Targets

Resolution

Notes

one-vs-one

~1–10 kb

Sequence of bait locus must be known

Data analysis low throughput

one-vs-all

~2 kb

Sequence of bait locus must be known

Detects novel contacts

Long-range contacts

many-vs-many

~1 kb

High dynamic range complete contact map of a locus 3C with ligation-mediated amplification (LMA) of a ‘carbon copy’ library of oligos designed across restriction fragment junctions of interest 3C

all-vs-all

0.1–1 Mb

Genome-wide nucleosome core positioning

Relative low resolution high cost

Interaction of whole genome mediated by protein

Depends on read depth and the size of the genome region bound by the protein of interest

Lower noise with ChIP

Biased method since selected protein

Previous2.2 Primary orderNextChap3 Computational analysis

Last updated 6 years ago

. Schematic Representation of Chromosome Conformation Capture (3C) and 3C-Derived Methods. These methods help to elucidate nuclear organization by detecting physical interactions between genetic elements located throughout the genome. Abbreviations: IP, immunoprecipitation; RE, restriction enzyme. Figure by Sotelo-Silveira, Mariana, et al. Trends in Plant Science (2018).

‘1’, ‘Many’ and ‘All’ indicate how many loci are interrogated in a given experiment. For example, ‘1 versus All’ indicates that the experiment probes the interaction profile between 1 locus and all other potential loci in the genome. ‘All versus All’ means that one can detect the interaction profiles of all loci, genome-wide, and their interactions with all other genomic loci .

Hi-C techniques has the highest through-put (billion reads per sample) but suffering of a relative low resolution of 0.1-1Mb. However, the other methods usually have a higher resolution around 1kb. For more details one can refer to table2 in .

Hi-C critical steps

Hi-C original:

Hi-C 1.0:

In situ Hi-C:

Single cell Hi-C:

DNase Hi-C

Hi-C 2.0:

DLO-Hi-C:

Hi-C improving:

Arima 1-day Hi-C:

3C

4C

5C

Hi-C

ChIA-PET

Figure1
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