July 18, 2023
Retrovirus-like retrotransposons help shape the genome evolution of their hosts and replicate within cytoplasmic particles. However, how their building blocks associate and assemble within the cell is poorly understood. A new study by Sean Beckwith and coworkers, recently published in PNAS, reports a prion-like domain (PrLD) in the Saccharomyces retrotransposon Ty1 Gag protein.
Gag, also found in retroviruses like HIV, is the structural protein that assembles virus-like particles (VLPs). The PrLD has similar sequence properties to prions and disordered protein domains that can drive the formation of assemblies that range from liquid to solid. The Ty1 PrLD acts like a prion when tested in a cell-based prionogenesis assay, and is essential for transposition (Ty1 doesn’t transpose without it!), but researchers were able to restore transposition by replacing the Ty1 PrLD with similar disordered sequences from yeast SUP35 and mouse PrP prions (how cool is that?!).
These findings from Beckwith et al. uncover a critical function for often overlooked disordered sequences, demonstrate greater flexibility in VLP assembly than previously appreciated, and establish an interchangeable “plug-and-play” platform to study disordered sequences in living cells – all by using the awesome power of yeast genetics (#APOYG!).
— Text from Sean Beckwith, with edits from SGD.
Categories: Research Spotlight