Figure 7

Qualitative co-localization of DNA and RNA through simultaneous imaging of RNA and DNA. Rat embryo fibroblasts were pulsed with ¹⁵N-uridine and BrdU as markers of newly synthesized RNA and DNA, respectively. (a,b) Parallel mass images at (a) ¹²C¹⁵N^- and (b) ⁸¹Br^-. (c) Overlay of ¹²C¹⁵N^- and ⁸¹Br^- images. ¹²C¹⁵N^- is depicted as red (R) and ⁸¹Br^- as green (G); the overlap between them shows up as yellow. (d) Overlay of ¹²C¹⁴N^- and ¹²C¹⁵N^- images. ¹²C¹⁴N^- is depicted as red (R) and ¹²C¹⁵N^- as green (G); the overlap between them shows up as yellow. Conditions of MIMS analysis: beam current 2pA; beam diameter 100 nm; field 20 × 20 μm.