Polyadenylation

Polyadenylation (pronounced: poh-lee-ad-uh-nuh-lay-shun) is a process in molecular biology that involves the addition of a poly(A) tail to a mRNA molecule.

Etymology

The term "Polyadenylation" is derived from the Greek words "poly" meaning many, and "adenylyl" referring to the adenosine molecule. The suffix "-ation" is used to denote the process.

Process

Polyadenylation occurs in the nucleus after the transcription process. The enzyme poly(A) polymerase adds a series of adenosine monophosphates to the 3' end of the mRNA molecule. This poly(A) tail protects the mRNA from degradation, aids in the export of the mature mRNA to the cytoplasm, and is involved in binding proteins involved in initiating translation (the process of synthesizing proteins from mRNA).

Related Terms

mRNA: Messenger RNA, a type of RNA that carries genetic information from DNA to the ribosome, where it specifies the amino acid sequence of the protein products of gene expression.
Transcription: The first step of gene expression, where a particular segment of DNA is copied into RNA by the enzyme RNA polymerase.
Translation: The process in which cellular ribosomes create proteins.
Nucleus: A membrane-bound organelle found in eukaryotic cells which contains most of the cell's genetic material.
Cytoplasm: The material within a living cell, excluding the cell nucleus. It comprises cytosol and the organelles – the cell's internal sub-structures.
Enzyme: A substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.