AAUAAA signal sequence

Introduction

Identifies poly-A site.

Eukaryotic primary transcripts are cleaved* by a specific endonuclease (CPSF) that recognizes the AAUAAA signal sequence. After cleavage, a poly[A]polymerase adds about 250 A residues to the 3' end of the mRNA to create a poly A tail.

* An additional 20 nucleotides 3' to the AAUAAA signal sequence is necessary for cleavage to occur. Since some mature mRNA molecules contain internal AAUAAA sequences, other features of the poly-A site are important

More general terms

• mRNA motif

Additional terms

• messenger RNA
• poly-A site
• poly-A tail