A role for the budding yeast separase, Esp1, in Ty1 element retrotransposition

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Separase (Esp1) is a protease crucial for sister chromatid separation during anaphase and mitotic exit.
• Its other cellular functions beyond cell cycle regulation are not fully understood.

Purpose of the Study:

• To identify novel roles of separase (Esp1) by conducting genome-wide genetic interaction screens.
• To investigate the potential involvement of Esp1 in Ty1 element retrotransposition.

Main Methods:

• Genome-wide genetic interaction screens were performed using a budding yeast esp1-1 mutant.
• Mass spectrometry and co-immunoprecipitation were used to identify interactions between Esp1 and Ty1 integrase.
• Ty1 transposition and insertion were analyzed in esp1-1 and cohesin mutant strains.

Main Results:

• Genetic screens identified genes involved in cell cycle, segregation, and notably, Ty1 retrotransposition.
• A direct interaction between Esp1 and Ty1 integrase was confirmed.
• Esp1 deficiency reduced Ty1 mobility and insertion, while cohesin mutations increased it.
• Securin (Pds1) is also required for efficient Ty1 transposition.

Conclusions:

• Separase (Esp1) plays a dual role in mediating Ty1 transposition.
• Esp1 facilitates Ty1 transposition by cohesin removal and by targeting Ty1 integrase to chromatin.
• These findings reveal a novel link between cell cycle machinery and retrotransposon activity.