Small t intron
You must add a |reason= parameter to this Cleanup template – replace it with {{Cleanup|August 2005|reason=<Fill reason here>}}, or remove the Cleanup template.
There exists a small T intron in some plasmid vectors used for protein expression.
The function of this intron in the vectors is unknown, but some guess that it might be involved in splicing or translation efficiency.
Vectors contain it, such as pME18s.