Untranslated region

The untranslated region (UTR) refers to the sections of an mRNA molecule that are not translated into protein. These regions are found on both the 5' and 3' ends of the mRNA and play crucial roles in the regulation of gene expression.

Structure

5' UTR

The 5' untranslated region (5' UTR) is located upstream of the start codon of the mRNA. It is involved in the regulation of translation initiation and can influence the efficiency of translation. The 5' UTR may contain regulatory elements such as ribosome binding sites, upstream open reading frames (uORFs), and internal ribosome entry sites (IRES).

3' UTR

The 3' untranslated region (3' UTR) is found downstream of the stop codon. It plays a role in the stability and localization of the mRNA, as well as in the regulation of translation. The 3' UTR often contains microRNA binding sites, polyadenylation signals, and other regulatory sequences that influence mRNA degradation and translation efficiency.

Function

Untranslated regions are critical for the post-transcriptional regulation of gene expression. They can affect mRNA stability, localization, and translation efficiency. The presence of specific sequences within UTRs can lead to the binding of regulatory proteins or non-coding RNAs, which modulate the fate of the mRNA.

Images

The central dogma of molecular biology, illustrating the flow of genetic information from DNA to RNA to protein.

Diagram of mRNA structure, showing the 5' cap, 5' UTR, coding sequence, 3' UTR, and poly(A) tail.

Related pages

• Messenger RNA
• Gene expression
• Translation (biology)
• MicroRNA