The article reviews the structure, functions, and mechanisms of mRNA untranslated regions (UTRs) in gene regulation. UTRs play crucial roles in controlling mRNA translation efficiency, stability, and subcellular localization. The 5' UTR and 3' UTR have distinct lengths and compositions, with the 5' UTR typically containing upstream initiation codons, open reading frames (ORFs), and stable secondary structures that can inhibit translation. The 3' UTR contains cis-acting elements such as AU-rich elements (AREs) that promote mRNA decay. UTRs also contain various motifs and structures that interact with RNA-binding proteins, affecting translation initiation and mRNA stability. Additionally, UTRs can influence mRNA localization through specific sequences or elements. The article highlights the importance of UTRs in gene regulation and their potential involvement in diseases when altered.The article reviews the structure, functions, and mechanisms of mRNA untranslated regions (UTRs) in gene regulation. UTRs play crucial roles in controlling mRNA translation efficiency, stability, and subcellular localization. The 5' UTR and 3' UTR have distinct lengths and compositions, with the 5' UTR typically containing upstream initiation codons, open reading frames (ORFs), and stable secondary structures that can inhibit translation. The 3' UTR contains cis-acting elements such as AU-rich elements (AREs) that promote mRNA decay. UTRs also contain various motifs and structures that interact with RNA-binding proteins, affecting translation initiation and mRNA stability. Additionally, UTRs can influence mRNA localization through specific sequences or elements. The article highlights the importance of UTRs in gene regulation and their potential involvement in diseases when altered.