In one to two sentences each, describe the three processes that commonly modify eukaryotic pre-mRNA.

Key Concepts

Capping

Capping is the addition of a modified guanine nucleotide to the 5' end of the pre-mRNA transcript. This cap protects the mRNA from degradation, assists in ribosome binding during translation, and plays a role in the export of the mRNA from the nucleus.

Polyadenylation

Polyadenylation involves the addition of a poly(A) tail, a sequence of adenine nucleotides, to the 3' end of the pre-mRNA. This modification enhances the stability of the mRNA, facilitates its export from the nucleus, and is crucial for translation initiation.

Splicing

Splicing is the process of removing non-coding sequences, known as introns, from the pre-mRNA and joining the coding sequences, called exons. This modification is essential for producing a mature mRNA that can be translated into a functional protein, allowing for the expression of specific genes.