The 2A peptides are a family of 18 to 22 amino acid self-cleaving peptides. Their common core sequence motif is DxExNPGP, and they are found in many viral families. They are 18 to 22 amino acid long and induce ribosomal skipping during translation.
The 2A peptide is a versatile tool for genetic engineering. It has been used to express multiple proteins at the same time in eukaryotic cells. To use the 2A peptide in gene expression systems, it must be inserted between the coding sequences of two or more genes. There are four variants of the peptide that have been tested for gene expression in a range of applications.
Td and GFP-tagged constructs are bi-cistronic, affecting the expression of the gene at the second position. They are designed to target Mef2c (M) and GFP (G). These constructs contain four 2As, and their positions differ by two to four.
The 2A peptide mediates a translational recoding event in which the ribosome elongates and skips formation of a specific glycylprolyl peptide bond. This enables the synthesis of two proteins from a single open reading frame.
As a self-cleavage peptide, T2A is also a useful subpart of a dual reporter system. It can be used between eGFP (BBa_K2807005) and mCherry (BBa_K2807006).