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DMS footprinting?|DMS footprinting method?|how DMS footprinting works?

                    
                             DMS footprinting

-        Dimethyl sulphate (DMS) is one of the oldest and most versatile chemical reagents used to probe RNA structure.
-        It was introduced for RNA structure mapping in 1980. This early method allowed detection of methylation by DMS at N7 of guanosine and N3 of cytidine nucleotide because of modification facilitate cleavage of the chain.
-        The sites of the methylation were determined by polyacrylamide gel electrophoresis (PAGE) analysis of end-labelled RNA.
-        Analogous method was used to footprint the binding of protein to DNA.
-        DMS footprinting is performed by binding the protein to its end labelled DNA target then attacking the DNA protein complex with DMS.
-        DMS footprinting follows a similar principle as fingerprinting except that the DNA methylation agent DMS, instead of DNase.
-        DMS foot printing which starts in the same ways as DNase footprinting with end


                 DMS footprinting (Dimethyl sulphate)

In vitro DNA protein interaction
DMS footprinting starts with end labelling of DNA and the protein
                                         ↓
DNA-protein complex is methylated with DMS (Mild treatment) i.e. only one methylation event occurs per DNA molecule.

                                        ↓
                   Protein is dislodge (removed)
                                       ↓
DNA treated with piperalin (baser amine) which removes methylated purines.

                      ↓
                    Creating a purine site

                     ↓
       Gel autoradiography to detect labelled DNA (Increases protein destroys the DNA double helix such that it makes the base corresponding more vulnerable to methylation)



Application: -
-        DMS footprinting has proven to be tremendously versitable method and has been applied to large fraction known structure RNS`s.
-        Initial application of the method concern. 



 Reference: -
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