Simultaneous Transport of Different Localized mRNA Species Revealed by Live-Cell Imaging

Traffic, 2008, 9 (doi:10.1111/j.1600-0854.2008.00763.x), 1256 published on 09.05.2008
Traffic, online article
Intracellular mRNA localization is a common mechanism to achieve asymmetric distributions of proteins. Previous studies have revealed that in a number of cell types, differentmRNA species are localized by the same transport machinery. However, it has been unclear if these individual mRNA species are specifically sorted into separate or common ribonucleoprotein (RNP) particles before or during transport. Using budding yeast as a model system, we analyzed the intracellular movement of individual pairs of localized mRNA in live cells. Yeast cells localize more than 20 differentmRNAs to the bud with the help of theMyo4p/She3p/She2p protein complex. For live cell imaging, mRNA pairs were tagged with tandem repeats of either bacteriophage MS2 or lambda boxB RNA sequences and fluorescently labeled by fusion protein constructs that bind to the RNAtag sequences.Using three-dimensional, single-particle tracking with dual-color detection, we have tracked the transport of two different localized mRNA species in real time. Our observations show that different localized mRNAs are coassembled into common RNP particles andcotransported in a directional manner to the target site. Nonlocalized mRNAs or mutant mRNAs that lack functional localization signals form separate particles that are not transported to the bud. This study reveals a high degree of co-ordination of mRNA trafficking in budding yeast.

CIPSM Movie
LMUexcellent
TU München
MPG
Helmholtz München
MPI of Neurobiology
MPI of Biochemistry