What is the significance of the untranslated region (UTR)?

UTRs are essential for post-transcriptional regulation of gene expression, influencing mRNA transport from the nucleus, maintaining mRNA stability, determining subcellular localization and regulating translation efficiency. UTRs contain specific sequences and structural elements that can affect the transport of mRNA molecules from the nucleus to the cytoplasm. These elements interact with various proteins and RNA-binding factors involved in mRNA export, ensuring that only mature, processed mRNAs are transported out of the nucleus for translation. The translation efficiency in mammalian cells is regulated by specific sequences found in the 5’- and 3-UTRs of mRNA molecules. These sequences serve as binding sites for regulatory proteins and RNAs. Examples of these regulatory elements include microRNA (miRNA) target sites, upstream open reading frames (uORFs), and polyadenylation elements. UTRs contain structural motifs which influence the stability of mRNA molecules. Certain elements within the UTRs, such as AU-rich elements (AREs) or GU-rich elements (GREs), can modulate the binding of RNA-binding proteins or microRNAs (miRNAs) that regulate mRNA degradation pathways.