Recode2 is a database of genes that utilize non-standard translation for gene expression purposes. Recoding events described in the database include programmed ribosomal frameshifting, translational bypassing (aka hopping) and mRNA specific codon redefinition. Frameshifting at a particular site often yields two protein products from one coding sequence and sometimes serves a regulatory purpose by acting as a sensor of the level of product protein or of some external ligand. Bypassing (hopping) allows the coupling of two ORFs separated on an mRNA by a coding gap. Codon redefinition occurs when a stop codon is decoded as a standard amino acid (often glutamine or tryptophan), or the 21st amino acid selenocysteine.
These recoding events are in competition with standard decoding and are site specific. The efficiency of recoding is often modulated by cis-stimulators and sometimes by trans-factors. The sequences of the genes that use recoding for their expression are in the database. The recoding sites and the known stimulatory signals are annotated in the database together with notes on factors that are known to affect recoding efficiencies.