Modifications of the DNA base cytosine have important roles in biology and their levels are commonly measured using a technique known as mass spectrometry. In this method, the DNA is first broken down into individual bases using enzyme-driven digestion. The mass of these individual units can then be measured and used to distinguish between, and calculate the amount of, each type of modified cytosine. 5-carboxycytosine (5caC) is a low abundance cytosine modification. However, Fang Yuan and colleagues from Chunxiao Song’s laboratory have discovered that 5caC makes DNA resistant to a commonly used enzyme for DNA digestion called PDE1, which results in a dramatic underestimation of the 5caC level. In their publication in the journal RSC Advances, they optimise the digestion method to increase the amount of detectable 5caC.
Improving 5-carboxycytosine detection
17 September 2019
A finding from Chunxiao Song’s group has implications for the quantification of this epigenetic modification by mass spectrometry.