The mature mRNA transcribed from the human β-globin gene is considerably longer than the sequence needed to encode the 146–amino acid polypeptide. Give the names of three sequences located on the mature β-globin mRNA but not translated.

Key Concepts

mRNA Structure

Messenger RNA (mRNA) is a single-stranded molecule that carries genetic information from DNA to the ribosome for protein synthesis. It consists of coding sequences (exons) that are translated into proteins and non-coding sequences (introns and untranslated regions) that play regulatory roles. Understanding the structure of mRNA is essential for identifying which parts are translated and which are not.

Untranslated Regions (UTRs)

Untranslated regions (UTRs) are segments of mRNA that are not translated into protein. They are found at both the 5' and 3' ends of the mRNA molecule and are crucial for regulating translation efficiency, stability, and localization of the mRNA. The 5' UTR often contains regulatory elements that influence ribosome binding, while the 3' UTR can affect mRNA stability and degradation.

Post-Transcriptional Modifications

Post-transcriptional modifications are processes that occur after the initial transcription of mRNA from DNA. These modifications include the addition of a 5' cap, polyadenylation at the 3' end, and splicing to remove introns. These changes are vital for mRNA stability, transport out of the nucleus, and proper translation, and they help define the mature mRNA that is ultimately translated into protein.