Team:Valencia/Safety

From 2010.igem.org

Sup35p

[PSI+] is a non-mendelian trait of Saccharomyces cerevisae that supress nonsense codons. This phenotype is due to a self-replication conformations of the protein Sup35p, a translation-termination factor. In [psi-] cells, the translation-termination factor Sup35 is soluble and functions with Sup45 to recognize stop codons and terminate translation.

The prion domain of Sup35 is Q/N Rich and has the ability to propogate the corresponding prion in the absence of the rest of the molecule. Source: Wickner et al. 2008.

In [PSI+] cells, most Sup35 is insoluble and nonfunctional, causing a reduction on translation fidelity. This trait is heritable because Sup35 protein in the [PSI+] conformation influences new Sup35 protein to adopt the same conformation and passes from mother cell to daughter to perpetuate the cycle of conversion. [PSI+] is, however, metaestable: [PSI+] cells occasionally give rise to [psi-] cells and viceversa, as the [PSI+] conformation is lost and gained.