What is the primary function of the polyA tail in eukaryotic mRNA?

The primary function of the polyA tail in eukaryotic mRNA is stabilization of the mRNA. The polyA tail, a long stretch of adenine nucleotides added to the 3' end of the mRNA molecule, plays a crucial role in protecting the mRNA from degradation by exonucleases in the cytoplasm. This stabilization contributes to the overall lifespan of the mRNA, ensuring that it remains intact long enough to be translated into protein.

In addition to stabilization, the polyA tail also assists in the regulation of translation and the export of the mRNA from the nucleus to the cytoplasm. It is recognized by protein factors that enhance translation efficiency and play a role in initiating the translation process by aiding the assembly of the ribosome on the mRNA strand.

The misconception that the function of the polyA tail is unknown overlooks its well-established roles in mRNA stability and regulation during gene expression. The polyA tail is a key feature that contributes to the integrity and functionality of eukaryotic mRNA.