Mutational Signatures in Human Intestinal Stem Cells During
Source Blokzijl et al. · Hubrecht Institute and University Medical Centre Utrecht, Utrecht, Netherlands · 10.1038/nature19768
Abstract
Used clonal organoid expansion and whole-genome sequencing to quantify somatic mutation accumulation in human intestinal stem cells across the human lifespan. Found approximately 40 mutations per stem cell per year with clock-like signatures (SBS1, SBS5), establishing the baseline somatic mutational landscape of normal intestine.
Protocol overview
28 steps across 9 phases
- 1 Obtain endoscopic biopsies
- 2 Obtain liver transplant biopsies
- 3 Obtain tumour-adjacent colon tissue
- 4 Dissociate intestinal crypts from biopsy samples
- 5 Isolate and culture hepatic cells from liver biopsies
- 6 Sort single cells by flow cytometry
- 7 Expand single cells into clonal organoid cultures
- 8 Collect clonal organoid cultures
- 9 Extract genomic DNA from clonal organoid cultures
- 10 Prepare reference samples (blood or biopsy)
- 11 Prepare Illumina sequencing libraries
- 12 Perform paired-end whole-genome sequencing
- 13 Align reads to reference genome
- 14 Mark duplicates and perform realignment
- 15 Call variants using GATK UnifiedGenotyper
- 16 Apply initial variant quality filters
- 17 Filter variants to obtain high-quality somatic mutations
- 18 Validate clonal origin using variant allele frequency analysis
- 19 Design amplicon primers for validation
- 20 Perform PCR amplification of candidate regions
- 21 Prepare amplicon sequencing libraries
- 22 Sequence amplicons on MiSeq platform
- 23 Validate variant calls
- 24 Perform extended in vitro culture
- 25 Perform second clonal expansion from extended cultures
- 26 Extract mutational signatures using NMF
- 27 Detect copy-number variations (CNVs)
- 28 Perform selection analysis (dN/dS ratio)
Full SOP
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Attribution
This SOP was authored by Organthis based on the published method in Blokzijl et al.. The originating laboratory holds no rights in this SOP and has not endorsed it unless marked Verified.
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