What structure is important for mRNA stability in eukaryotes?

The cap and tail are crucial for mRNA stability in eukaryotes. The 5' cap is a modified guanine nucleotide that is added to the beginning of the mRNA transcript. This cap protects the mRNA from degradation by exonucleases, enzymes that can degrade RNA molecules from their ends. Additionally, the cap assists in ribosome binding during the initiation of translation, which is essential for protein synthesis.

At the 3' end of the mRNA, a poly-A tail, consisting of a long chain of adenine nucleotides, is added. This tail also plays a significant role in stability, as it further protects the mRNA from degradation and is involved in the termination of transcription and the export of mRNA from the nucleus to the cytoplasm. Both the cap and the poly-A tail work together to ensure that mRNA remains intact long enough to be translated into proteins, making them vital for proper gene expression in eukaryotic cells.