Cotranscriptional mRNP assembly: from the DNA to the nuclear pore.

Transcription is coupled with the concomitant assembly of RNA-binding proteins to the nascent mRNA to generate a stable and export-competent mRNP particle. RNA-binding factors recruited at active transcription sites specify the processing, nuclear export, subcellular localization, translation and stability of the mRNA. The assembly of the mRNP particle starts with the association of the cap-binding protein complex followed by the splicing-dependent assembly of the exon-junction complex in intron-containing genes and by the binding of RNA-export adaptor proteins. New findings suggest that mRNP assembly is a genetically controlled process that plays a key role in gene expression and other cellular processes, including the maintenance of genome integrity.