Yeast Colony Transformations

Protocol based on Morita & Takegawa 2004

Fast and convenient transformation protocol for fission yeast. This method is not as efficient as the Yeast Chemical Transformations or the Yeast Electoporation Transformation. The cells are grown on a plate to form a colony that is then scraped of the medium, resuspended in transformation medium and immediately used for transformation.

1. Suspend cells of the to-be-transformed strain in sterile saline or water
2. Pipette the cells on YES in 10µl droplets
3. Incubate the plate for 24-48 hours at 32°C to form a fat colony of about 5mm
4. Prepare a tube with 50µl PLATE mixture.
   • 50% Polyethylene glycol (PEG)‐4000
   • Lithium Acetate 100mM
   • 10 mM Tris-HCl
   • 1mM EDTA
5. Scrape the cells of the plate with a sterile toothpick and suspend in the PLATE
6. Add 5µl ssDNA and mix
7. Add plasmid and/or Homologous DNA (about 1 µg) and mix
8. Incubate for 4h at 32°C
9. Place on ice for 15 min
10. Heatshock the mix at 42°C for 15 minutes
11. Centrifuge the cells at 1600 x g for 3 min at room temperature (RT).
12. Remove supernatant and re-suspend the cells in 1 ml
    • EMM-N or
    • EMM when working with h⁹⁰ or an other homothallic strain

    Reduce the added supplements (e.g. leucine, adenine etc) to 10% of the standard amount.

13. Incubate at RT for ~16h
14. Spin down the cells at 1600 x g for 3 min, RT and remove supernatant
15. Resuspend cells in 100 μl water and spread them on YES plates with appropriate selective agent (1 in 1000 Nourseothricin (100 μg/μl) or 1 in 500 G418 (50mg/ml)).
16. Incubate at 32°C for at least 3 days (but more likely 4 to 5)