How would you test the extent of the mRNA's/DNA's impact within the cell? Is it possible to do something like tagging the molecules with radioisotopes and foll

How would you test the extent of the mRNA's/DNA's impact within the cell? Is it possible to do something like tagging the molecules with radioisotopes and following their path? Here's an example: https://www.nejm.org/doi/full/10.1056/NEJM199001253220403 https://www.nejm.org/doi/full/10.1056/NEJM199001253220403