We now know MicroRNAs (miRNAs) have big positive and negative impact on replication in DNA viruses, but what about RNA viruses like influenza? The authors of a new study just released by mBio went looking for miRNAs made by the flu virus, but they made an unexpected discovery that may provide insights that can help in the treatment of the flu.
Instead of miRNAs, Umbach et al. found that influenza virus generates tens of thousands of short (18-27 nt long) viral leader RNAs (leRNAs) that originate from the very 5’ end of all eight viral RNA segments. They detected around 100,000 leRNAs per cell. Why so many? The high level of expression of viral leRNAs suggests they play an important role in the virus replication cycle and they could represent a novel target for the treatment of flu.