Abstract
In eukaryotes, the messenger RNA (mRNA), the blueprint of a protein-coding gene, is processed and packaged into a messenger ribonucleoprotein particle (mRNP) by mRNA-binding proteins in the nucleus. The steps of mRNP formation - transcription, processing, packaging, and the orchestrated release of the export-competent mRNP from the site of transcription for nuclear mRNA export - are tightly coupled to ensure a highly efficient and regulated process. The importance of highly accurate nuclear mRNP formation is illustrated by the fact that mutations in components of this pathway lead to cellular inviability or to severe diseases in metazoans. We hypothesize that efficient mRNP formation is realized by a molecular mRNP packaging station, which is built by several recruitment platforms and coordinates the individual steps of mRNP formation.