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[Audrey CHAMPIER]

                                                                ChIP-Seq 

Methode used to analyse the interactions between proteins and DNA.

The technique consists in a chromatin  immunoprecipitation followed by a parallel DNA  sequencing in order to identify the binding sites of one protein on DNA. ( Before it, scientists used Chip on Chip : Chromatin immunoprecipitation + sequencing with  DNA -microarray technique )

Chromatin immunoprecipitation :   ( for more details see  : " Wet-Lab portion of the workflow in the following link" :  https://en.wikipedia.org/wiki/ChIP-on-chip#Workflow_of_a_ChIP-on-chip_experiment)

The protein of interest is first cross-linked with the  DNA site it binds,  thanks to formaldehyde for example.

Then the cells are lysed and the DNA , thanks to sonication, becomes small fragments.

After this , we introduce an antibody specific of  the protein that interests us.  This antibodies are bound to a surface and so we obtain,on this surface, all the sequence of DNA that bind the protein. In order to obtain only the DNA sequence, we reverse the cross-linking of DNA and proteins,  thanks to heat.

Sequencing:  

We use Parallel DNA sequencing method in order to obtain the sequence of all the fragments of DNA we just obtained with immunoprecipitation. 

For more informations see: 

https://en.wikipedia.org/wiki/ChIP-sequencing#ChIP