Gene Expression is one of the fundamental processes of life. In eukaryotes, the mRNA is synthesized by RNA polymerase II transcribing the protein-coding genes. Already largely cotranscriptionally, the mRNA is processed, i.e. capped, spliced and polyadenylated, and packaged by binding of RNA-binding proteins (RBPs) into a messenger ribonucleprotein particle (mRNP). Binding of these nuclear RBPs to the mRNA determines essential steps during the later life of the mRNA such as its nuclear export, translation rate and stability. Thus, packaging of the mRNA into an mRNP is an essential step of gene expression.

We use the yeast S. cerevisiae to elucidate the mechanism and function of mRNP packaging because in this model organism all the nuclear mRNP components are – most likely – known. However, the coordinated assembly as well as the changing composition and structure of an mRNP has remained largely enigmatic despite a lot of research in this field. I will review our current knowledge of mRNP packaging and also report novel insights into this process from recent research of my laboratory.