Rapid purification of DNA samples from dextran sodium sulfate (DSS) contaminants

Dextran sodium sulfate (DSS) is widely used to model colonic inflammation and colorectal cancer. However, it is a potent inhibitor of DNA polymerase, necessitating its removal prior to downstream analysis. Currently, there is no robust, widely applicable method of removing DSS from DNA samples. Here, we demonstrate that cetyltrimethylammonium bromide (CTAB) buffer enables rapid and efficient removal of DSS from mouse stool DNA. In the absence of CTAB, DSS inhibited PCR reactions at concentrations of 136 nM and above. CTAB effectively removed DSS from DNA samples processed by both phenol-chloroform extraction and column cleanup kits. 700 μL of CTAB was able to remove up to 93 nmol (4 mg) of DSS after one round of cleanup, while two rounds removed up to 465 nmol (20 mg) of DSS. Purified genomic DNA was suitable for subsequent quantitative PCR analysis.