| First Author | Querido E | Year | 2011 |
| Journal | J Cell Sci | Volume | 124 |
| Issue | Pt 10 | Pages | 1703-14 |
| PubMed ID | 21511730 | Mgi Jnum | J:182946 |
| Mgi Id | MGI:5317226 | Doi | 10.1242/jcs.073270 |
| Citation | Querido E, et al. (2011) Stochastic and reversible aggregation of mRNA with expanded CUG-triplet repeats. J Cell Sci 124(Pt 10):1703-14 |
| abstractText | Transcripts containing expanded CNG repeats, which are found in several neuromuscular diseases, are not exported from the nucleus and aggregate as ribonuclear inclusions by an unknown mechanism. Using the MS2-GFP system, which tethers fluorescent proteins to a specific mRNA, we followed the dynamics of single CUG-repeat transcripts and RNA aggregation in living cells. Single transcripts with 145 CUG repeats from the dystrophia myotonica-protein kinase (DMPK) gene had reduced diffusion kinetics compared with transcripts containing only five CUG repeats. Fluorescence recovery after photobleaching (FRAP) experiments showed that CUG-repeat RNAs display a stochastic aggregation behaviour, because individual RNA foci formed at different rates and displayed different recoveries. Spontaneous clustering of CUG-repeat RNAs was also observed, confirming the stochastic aggregation revealed by FRAP. The splicing factor Mbnl1 colocalized with individual CUG-repeat transcripts and its aggregation with RNA foci displayed the same stochastic behaviour as CUG-repeat mRNAs. Moreover, depletion of Mbnl1 by RNAi resulted in decreased aggregation of CUG-repeat transcripts after FRAP, supporting a direct role for Mbnl1 in CUG-rich RNA foci formation. Our data reveal that nuclear CUG-repeat RNA aggregates are labile, constantly forming and disaggregating structures, and that the Mbnl1 splicing factor is directly involved in the aggregation process. |
