The localization of mRNA to defined cytoplasmic sites in eukaryotic cells not 
only allows localized protein production but also determines the fate of mRNAs. 
For instance, translationally repressed mRNAs localize to P-bodies and stress 
granules where their decay and storage, respectively, are directed. Here, we 
find that several mRNAs are localized to granules in unstressed, actively 
growing cells. These granules play a key role in the stress-dependent formation 
of P-bodies. Specific glycolytic mRNAs are colocalized in multiple granules per 
cell, which aggregate during P-body formation. Such aggregation is still 
observed under conditions or in mutants where P-bodies do not form. In 
unstressed cells, the mRNA granules appear associated with active translation; 
this might enable a coregulation of protein expression from the same pathways or 
complexes. Parallels can be drawn between this coregulation and the advantage of 
operons in prokaryotic systems.