Equine Rhinitis A Virus 2A (E2A) Self-Cleaving Peptide
Self-cleaving 2A peptide from equine rhinitis A virus, third in efficiency among the four viral 2A peptides. Used in multi-cistronic constructs where P2A and T2A are unsuitable due to sequence context constraints or repeated element concerns.
Origin: Equine rhinitis A virus 2A region
Characteristics
Core 20 aa peptide (QCTNYALLKLAGDVESNPGP), 60 bp coding sequence. Cleavage efficiency is lower than P2A and T2A but higher than F2A in head-to-head comparisons across human cell lines and in vivo models. Uses the same ribosomal skipping mechanism. Provides a useful alternative when sequence diversity among 2A sites is needed to avoid recombination in vectors containing multiple 2A elements. Often combined with P2A or T2A in tricistronic constructs.
Applications: Tricistronic constructs requiring a third distinct 2A sequence to minimize recombination risk between repeated elements. Situations where sequence diversity across multiple 2A sites in a single vector is required. Alternative when P2A or T2A show context-dependent cleavage issues.
Limitations: Lower cleavage efficiency than P2A and T2A. More residual uncleaved fusion protein detectable by western blot compared to P2A. Less commonly used as a primary 2A element; mainly chosen for sequence diversity purposes.
Sequence
References
- Kim et al. (2011). High cleavage efficiency of a 2A peptide derived from porcine teschovirus-1 in human cell lines, zebrafish and mice. PLoS ONE - Kim 2011 P2A Cleavage