FAQ: Do you have a protocol for separating small and large RNAs into separate fractions?
Yes, the Monarch RNA Cleanup Kit manual contains a protocol which will separate RNA into RNAs > 200 nt and < 200 nt. The protocol can also be accessed online. Following this protocol enriches RNA below 200 nt into the “small RNA” fraction, while RNA above 200 nt is enriched in the “large RNA” fraction. No fractionation protocol allows precise separation of similarly sized RNA based on length alone. We find RNA between 100–200 nt will preferentially partition to the different fractions based on various factors, including predicted secondary structure and interactions with other RNAs within the sample. Highly structured molecules between 100–200 nt typically fall into the small RNA fraction while unstructured RNA between 100–200 nt fall into the large RNA fraction.