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How to check wether Chip-seq worked or not

Hello every one I have done the Chip analysis for illumina paired end reads(150 PE), aligned the reads to mm10 genome using bowtie2, and removed the duplicates using picard mark duplicates and peak calling using macs2 (Input, H3K4me3, c-Myc)

mac2 callpeak -t H3K4me3.bam -c Input.bam -f BAMPE -g mm -q 0.05 -n H3K4me3

mac2 callpeak -t c-Myc.bam -c Input.bam -f BAMPE -g mm -q 0.05 -n c-Myc

Incase of H3K4me3 i am getting around 20000 peaks and c-Myc only 10 peaks can any one suggest is there any fault in my pipeline or chip didnt work

please suggest me what are the possibilities I can check

Thank you

chip-seq sequencing alignment

2 answers

Easy way is to use plotFingerprint from deepTools to check if the antibody used gives any enrichment in your experiment.

Hi,

It looks like you have very minimal enrichment over input compared to IgG. I would always prefer Input over IgG for ChIP control. The peak numbers you mentioned above, was it over IgG or Input?

Also I am just wondering how you got 20,000 peaks for H3K4me3 since the enrichment was not that prominent. It is better to load the peaks in genome browser (IGV) and check some of the top and bottom enriched regions manually. Sometimes MACS doesn't work for antibody with minimal enrichment in the experiment (it just starts reporting random short regions).

Peak number mentioned is over Input, is there any necessary to make all sample with same library size.

Make a bigwig, e.g. with bamCoverage from deeptools and just look at the data. You will see whether there is signal (=peaks) or just noise. Ten peaks sounds like a failed ChIP.

yes, I tried your mentioned method, very less signal I am getting there is no significant peak I can see in that particular regions. Is there any other way I can improve macs2 peak calling with any parameters please let me know

Thank you

Not that I know, macs2 is awesomely robust. If you do not see peaks by eye then odds are good your ChIP is simply crappy.

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