NanoRNAs Prime Transcription Initiation In Vivo

作者：Goldman Seth R; Sharp Josh S; Vvedenskaya Irina O; Livny Jonathan; Dove Simon L^*; Nickels Bryce E

来源：Molecular Cell, 2011, 42(6): 817-825.

DOI：10.1016/j.molcel.2011.06.005

It is often presumed that, in vivo, the initiation of RNA synthesis by DNA-dependent RNA polymerases occurs using NTPs alone. Here, using the model Gram-negative bacterium Pseudomonas aeruginosa, we demonstrate that depletion of the small-RNA-specific exonuclease, Oligoribonuclease, causes the accumulation of oligoribonucleotides 2 to similar to 4 nt in length, "nanoRNAs," which serve as primers for transcription initiation at a significant fraction of promoters. Widespread use of nanoRNAs to prime transcription initiation is coupled with global alterations in gene expression. Our results, obtained under conditions in which the concentration of nanoRNAs is artificially elevated, establish that small RNAs can be used to initiate transcription in vivo, challenging the idea that all cellular transcription occurs using only NTPs. Our findings further suggest that nanoRNAs could represent a distinct class of functional small RNAs that can affect gene expression through direct incorporation into a target RNA transcript rather than through a traditional antisense-based mechanism.

• 出版日期2011-6-24