Combining combing and secondary ion mass spectrometry to study DNA on chips using13C and15N labeling

摘要

Dynamic secondary ion mass spectrometry ( D-SIMS) imaging of combed DNA – the combing, imaging by SIMS or CIS method – has been developed previously using a standard NanoSIMS 50 to reveal, on the 50 nm scale, individual DNA fibers labeled with different, non-radioactive isotopes in vivo and to quantify these isotopes. This makes CIS especially suitable for determining the times, places and rates of DNA synthesis as well as the detection of the fine-scale re-arrangements of DNA and of molecules associated with combed DNA fibers. Here, we show how CIS may be extended to ¹³C-labeling via the detection and quantification of the ¹³C ¹⁴N ^- recombinant ion and the use of the ¹³C: ¹²C ratio, we discuss how CIS might permit three successive labels, and we suggest ideas that might be explored using CIS.