File size: 7,993 Bytes
3b39456 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 | #!/bin/bash
set -e
# =============================================================================
# ChIP-seq Peak Calling: TAL1 Binding Site Identification
# Pipeline: trimmomatic -> bwa -> samtools -> macs2 -> bedtools -> deeptools
# Data: Mouse G1E cells + Megakaryocytes, TAL1 ChIP-seq (chr19 subset)
# Source: Galaxy Training Network / Wu et al. 2014 (GEO GSE51338)
# =============================================================================
THREADS=$(( $(nproc) > 8 ? 8 : $(nproc) ))
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
DATA_DIR="${SCRIPT_DIR}/data"
REF_DIR="${SCRIPT_DIR}/reference"
OUT_DIR="${SCRIPT_DIR}/outputs"
RESULTS_DIR="${SCRIPT_DIR}/results"
log_step() {
echo "=================================================================="
echo "STEP: $1"
echo "=================================================================="
echo "Started at: $(date)"
}
mkdir -p "${OUT_DIR}/trimmed" "${OUT_DIR}/aligned" "${OUT_DIR}/peaks" "${OUT_DIR}/comparison"
mkdir -p "${RESULTS_DIR}"
REF="${REF_DIR}/mm10_chr19.fa"
# ==========================================================================
# STEP 1: Index reference genome (bwa)
# ==========================================================================
log_step "Indexing reference with bwa"
bwa index "${REF}"
samtools faidx "${REF}"
# ==========================================================================
# STEP 2: Trim reads (trimmomatic)
# ==========================================================================
log_step "Trimming reads with trimmomatic"
for SAMPLE in G1E_input_R1 G1E_input_R2 G1E_Tal1_R1 G1E_Tal1_R2 \
Mega_input_R1 Mega_input_R2 Mega_Tal1_R1 Mega_Tal1_R2; do
echo " Trimming ${SAMPLE}..."
trimmomatic SE -threads ${THREADS} \
"${DATA_DIR}/${SAMPLE}.fastq" \
"${OUT_DIR}/trimmed/${SAMPLE}.trimmed.fastq" \
SLIDINGWINDOW:4:20
done
# ==========================================================================
# STEP 3: Align reads to reference (bwa mem)
# ==========================================================================
log_step "Aligning reads with bwa mem"
for SAMPLE in G1E_input_R1 G1E_input_R2 G1E_Tal1_R1 G1E_Tal1_R2 \
Mega_input_R1 Mega_input_R2 Mega_Tal1_R1 Mega_Tal1_R2; do
echo " Aligning ${SAMPLE}..."
bwa mem -t ${THREADS} "${REF}" "${OUT_DIR}/trimmed/${SAMPLE}.trimmed.fastq" \
| samtools sort -@ ${THREADS} -o "${OUT_DIR}/aligned/${SAMPLE}.bam"
samtools index "${OUT_DIR}/aligned/${SAMPLE}.bam"
done
# ==========================================================================
# STEP 4: Alignment statistics (samtools idxstats)
# ==========================================================================
log_step "Generating alignment statistics with samtools"
echo -e "sample\tref\tlength\tmapped\tunmapped" > "${RESULTS_DIR}/alignment_stats.tsv"
for SAMPLE in G1E_input_R1 G1E_input_R2 G1E_Tal1_R1 G1E_Tal1_R2 \
Mega_input_R1 Mega_input_R2 Mega_Tal1_R1 Mega_Tal1_R2; do
samtools idxstats "${OUT_DIR}/aligned/${SAMPLE}.bam" \
| awk -v s="${SAMPLE}" 'BEGIN{OFS="\t"} {print s, $1, $2, $3, $4}' \
>> "${RESULTS_DIR}/alignment_stats.tsv"
done
# ==========================================================================
# STEP 5: Peak calling with MACS2 — G1E cells
# ==========================================================================
log_step "Calling peaks for G1E with macs2"
macs2 callpeak \
-t "${OUT_DIR}/aligned/G1E_Tal1_R1.bam" "${OUT_DIR}/aligned/G1E_Tal1_R2.bam" \
-c "${OUT_DIR}/aligned/G1E_input_R1.bam" "${OUT_DIR}/aligned/G1E_input_R2.bam" \
-f BAM -g mm --call-summits \
-n G1E_TAL1 --outdir "${OUT_DIR}/peaks/"
# ==========================================================================
# STEP 6: Peak calling with MACS2 — Megakaryocytes
# ==========================================================================
log_step "Calling peaks for Megakaryocytes with macs2"
macs2 callpeak \
-t "${OUT_DIR}/aligned/Mega_Tal1_R1.bam" "${OUT_DIR}/aligned/Mega_Tal1_R2.bam" \
-c "${OUT_DIR}/aligned/Mega_input_R1.bam" "${OUT_DIR}/aligned/Mega_input_R2.bam" \
-f BAM -g mm --call-summits \
-n Mega_TAL1 --outdir "${OUT_DIR}/peaks/"
# ==========================================================================
# STEP 7: Compare peaks between cell types (bedtools intersect)
# ==========================================================================
log_step "Comparing peaks with bedtools"
# Common peaks (shared between G1E and Megakaryocytes)
bedtools intersect \
-a "${OUT_DIR}/peaks/G1E_TAL1_peaks.narrowPeak" \
-b "${OUT_DIR}/peaks/Mega_TAL1_peaks.narrowPeak" \
> "${OUT_DIR}/comparison/common_peaks.bed"
# G1E-unique peaks
bedtools intersect \
-a "${OUT_DIR}/peaks/G1E_TAL1_peaks.narrowPeak" \
-b "${OUT_DIR}/peaks/Mega_TAL1_peaks.narrowPeak" \
-v > "${OUT_DIR}/comparison/g1e_unique_peaks.bed"
# Megakaryocyte-unique peaks
bedtools intersect \
-a "${OUT_DIR}/peaks/Mega_TAL1_peaks.narrowPeak" \
-b "${OUT_DIR}/peaks/G1E_TAL1_peaks.narrowPeak" \
-v > "${OUT_DIR}/comparison/mega_unique_peaks.bed"
# ==========================================================================
# STEP 8: Normalized signal tracks (deeptools bamCompare)
# ==========================================================================
log_step "Computing normalized signal with deeptools bamCompare"
bamCompare \
-b1 "${OUT_DIR}/aligned/G1E_Tal1_R1.bam" \
-b2 "${OUT_DIR}/aligned/G1E_input_R1.bam" \
--operation log2 --binSize 50 \
-p ${THREADS} \
-o "${OUT_DIR}/comparison/G1E_R1_log2ratio.bw"
bamCompare \
-b1 "${OUT_DIR}/aligned/Mega_Tal1_R1.bam" \
-b2 "${OUT_DIR}/aligned/Mega_input_R1.bam" \
--operation log2 --binSize 50 \
-p ${THREADS} \
-o "${OUT_DIR}/comparison/Mega_R1_log2ratio.bw"
# ==========================================================================
# STEP 9: Generate final results CSV
# ==========================================================================
log_step "Generating final results"
# Main output: peak comparison summary with coordinates and scores
echo "chrom,start,end,name,score,strand,signal_value,pvalue,qvalue,peak,cell_type,status" \
> "${RESULTS_DIR}/peak_comparison.csv"
# G1E peaks — mark shared vs unique
awk 'BEGIN{OFS=","} {print $1,$2,$3,$4,$5,$6,$7,$8,$9,$10,"G1E","shared"}' \
"${OUT_DIR}/comparison/common_peaks.bed" >> "${RESULTS_DIR}/peak_comparison.csv"
awk 'BEGIN{OFS=","} {print $1,$2,$3,$4,$5,$6,$7,$8,$9,$10,"G1E","unique"}' \
"${OUT_DIR}/comparison/g1e_unique_peaks.bed" >> "${RESULTS_DIR}/peak_comparison.csv"
# Megakaryocyte peaks — shared vs unique
awk 'BEGIN{OFS=","} {print $1,$2,$3,$4,$5,$6,$7,$8,$9,$10,"Megakaryocyte","shared"}' \
"${OUT_DIR}/comparison/common_peaks.bed" >> "${RESULTS_DIR}/peak_comparison.csv"
awk 'BEGIN{OFS=","} {print $1,$2,$3,$4,$5,$6,$7,$8,$9,$10,"Megakaryocyte","unique"}' \
"${OUT_DIR}/comparison/mega_unique_peaks.bed" >> "${RESULTS_DIR}/peak_comparison.csv"
# Summary stats
TOTAL_G1E=$(wc -l < "${OUT_DIR}/peaks/G1E_TAL1_peaks.narrowPeak")
TOTAL_MEGA=$(wc -l < "${OUT_DIR}/peaks/Mega_TAL1_peaks.narrowPeak")
COMMON=$(wc -l < "${OUT_DIR}/comparison/common_peaks.bed")
G1E_UNIQUE=$(wc -l < "${OUT_DIR}/comparison/g1e_unique_peaks.bed")
MEGA_UNIQUE=$(wc -l < "${OUT_DIR}/comparison/mega_unique_peaks.bed")
echo "metric,value" > "${RESULTS_DIR}/peak_summary.csv"
echo "g1e_total_peaks,${TOTAL_G1E}" >> "${RESULTS_DIR}/peak_summary.csv"
echo "mega_total_peaks,${TOTAL_MEGA}" >> "${RESULTS_DIR}/peak_summary.csv"
echo "common_peaks,${COMMON}" >> "${RESULTS_DIR}/peak_summary.csv"
echo "g1e_unique_peaks,${G1E_UNIQUE}" >> "${RESULTS_DIR}/peak_summary.csv"
echo "mega_unique_peaks,${MEGA_UNIQUE}" >> "${RESULTS_DIR}/peak_summary.csv"
echo ""
echo "=== Pipeline complete ==="
echo "Results in: ${RESULTS_DIR}/"
ls -lh "${RESULTS_DIR}/"
cat "${RESULTS_DIR}/peak_summary.csv"
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