"mRNA IMPRINTING": REGULATION OF GENE EXPRESSION BY CO-TRANSCRIPTIONALLY ASSOCIATING PROTEINS

Relatively little is known today about the coordination between the stages of the RNA life-cycle. Such coordination is of the utmost importance in the maintenance of an apt proteome. We propose that the coordination and communication between these stages directly affects the fate of the mRNA and gene expression. A number of studies have shown cases of cross-talks between mRNA synthesis, processing, export, and decay. However, these studies are incomplete. We propose that a decision making process whether to express a gene and the extent of its expression involves communication between all stages. Moreover, the fate of the mRNA is already determined during transcription, even before its synthesis is completed. We have ascertained a broad scope of the proteins that associate with the mRNA from transcription and accompany it throughout its life-cycle. Amongst those found are translation factors and ribosomal subunits as well as the ribonuclease XRN1. The presence of these proteins indicates that the mRNA`s translatability and stability may very well be imprinted during transcription. Under different conditions or stresses, these co-transcriptionally associated proteins are subject to change, indicating their role in regulation of gene expression. These new findings bring yet more complexity in the known interactions within the lifespan of mRNA.