How Are Cellular RNAs Targeted For Maturation And Degradation?

Summary

The central dogma of molecular biology states that DNA makes RNA makes protein. The process of transcription, whereby DNA is "copied" into mRNA (messenger RNA) is the intermediate step in the production of proteins. However, the majority of transcription that takes place in a cell results in the production of RNA molecules that do not, in fact, encode for proteins.

These diverse RNA species fall into various categories which can be divided based upon their structure, function and the proteins with which they associate with. The multiple species of RNA carry out a plethora of functions in a cell from catalysing chemical reactions to controlling levels of protein expression. Many of these RNA species, including mRNA, are not transcribed in their final functional form, and are subject to processing events in order to achieve their mature state.

Further, these events are tightly regulated to ensure that the production of the RNA is accurate. If a fault in their production occurs, the aberrant RNA specie is subject to degradation, so as to prevent defective machinery engaging in the cell. One key factor that is implicated in both the maturation and degradation of almost all species of RNA is the exosome complex, which has the ability to remove specific regions of the RNA during processing or digest the complete RNA during degradation.

One of the great conundrums is how the exosome recognises and is targeted to its numerous different RNA species. This project will uncover how the different RNA species are recognised.