RBPed

RBPed is a bioinformatics pipeline to identify differential RNA editing events between eCLIP-seq and RNA-seq

Authors

Xiaolin Hu, Qin Zou, Li Yao and Xuerui Yang

1. python dependency

RBPed was compromised by samtools, REDItools V1, and R. Among those softwares, REDItools V1 depends on python2.7, besides, it depends on pysam 0.7.6. You can install with code:

• python -m pip install pysam==0.7.6

Also, it depends on some bioinformatics packages

• samtools

2. reference file

the reference genome (hg19) downloaded from GENCODE website. Known editing events downloaded from REDIportal database. Those data can be downloaded within this pipeline.

3. Run

• A. Downloading mapping files (bam) from ENCODE websites.

wget http://srv00.recas.ba.infn.it/webshare/ATLAS/donwload/TABLE1_hg19.txt.gz
gunzip TABLE1_hg19.txt.gz
grep -v 'Region' TABLE1_hg19.txt |awk '{print $1,$2,$5}' | sed 's/ /\t/g' | sed 's/chr//g' | sort -k1,1 -k2,2n  > REDIportals.forREDItools.txt

wget https://ftp.ebi.ac.uk/pub/databases/gencode/Gencode_human/release_40/GRCh37_mapping/GRCh37.primary_assembly.genome.fa.gz
gunzip GRCh37.primary_assembly.genome.fa.gz
sed 's/chr//g' GRCh37.primary_assembly.genome.fa > hg19.ref.fa

• B. Sort, index bam files

samtools  sort --threads 16  -o XXX.sorted.bam XXX.eCLIP.bam
samtools index XXX.sorted.ba

• C. Detection RNA editing events with REDItools.

Notice: if this code not work out properly, chromosome name (with chr or not) should be checked in bam, reference and REDIportals data.

python2.7 REDItoolKnown.py  -i XXX.sorted.bam -f hg19.ref.fa -l REDIportals.forREDItools.txt -t 16 -c 10 -T 6-0  -p -e -d -u -m20  -v 0 -n 0.0 -o outputDir

• D. Merge RNA editing events in different replicate and between different eCLIP and RNA-seq

• E. Using R to calculate delta editing levels and fisher test P-values. core code listed:

Pvalue=list()
i=1
while(i<=dim(data)[1]){
data2=data[i,]
#V7 is number of base I in eclip, V8 is total base covered this site in ECLIP, V11 is number of base I in RNA-seq ,V10 is total base covered this site in RNA-seq.
Pvalue[i]=fisher.test(matrix(c(data2$V7,data2$V11-data2$V7,data2$V8,data2$V10-data2$V8),nrow=2,ncol=2))$p.value
i=i+1 
}

delta=data$V7/data$V8-data$V11/data$V10
m2=cbind(data,unlist(Pvalue),delta,eclipEL=data$V7/data$V8,RNAEL=data$V11/data$V10)

License

RBPed is licensed under the MIT license