What radioactive compounds can be used to label RNA ? DNA?

Question

What radioactive compounds can be used to label RNA ? DNA?

Answer 1

C-14 uracil is used to label RNA and C-14 thymine is used to label DNA. Only uracil is present in RNA, and only thymine is present in DNA.

Answer 2

I work in a research lab and we regularly label RNA using S-35 and P-32.

We buy nucleotides (to synthesize a RNA strand) that are already labeled.

For the P-32 compound, one of the phosphates in the nucleotide is simply replaced with a isotope.

For the S-35 compound, one of the oxygens in a phosphate group is replaced with a sulfur isotope.