High-throughput assays for RNA polymerases using MALDI MS and PEAs

RNA polymerase enzymes are critical proteins involved in RNA stability and degradation and are implicated in regulating microRNAs, histone mRNAs, along with viral RNAs. Some RNA polymerases are important to restore degradation of oncogenic RNAs, offering a promising therapeutic strategy. Traditional biochemical assays that measure RNA activity rely on indirect measurements such as the generation of a pyrophosphate biproduct, or FRET assays that utilize a third component that binds to the newly synthesized strand to generate a FRET signal. Here, we demonstrate the use of MALDI mass spectrometry polymeric enrichment arrays (PEAs) to enable a direct readout of the RNA products, offering a robust and high-throughput assay to measure polymerase activity on any oligonucleotide.