IGEM:University of Chicago/2009/Protocols

Media/Solutions

Solutions for LiAc Yeast Transformations

LiAc Mix (Store RT, Sterile filter), 500mL

• H2O--400mL
• 100mM LiAc--50mL of 1M LiAc
• TE (10mM Tris+1mM EDTA, pH8)-- 50mL of 10X TE

PEG Mix (Store RT, Sterile filter), 10mL

• 40% PEG mw 3350--8mL of 50% PEG Sterile filtered
• 100mM LiAc--1mL of 1M LiAc
• TE--1mL of 10X TE

SOS (make fresh), 10mL

• 33%YEP--3.4mL of YEP(or YPD)
• H2O--6.6mL of H2O
• 6.5mM CaCl--65µl of 1M CaCl

Yeast transformations

Pryciak Lab LiAc Yeast Transformation

• Standard Small Scale Protocol

• 50mL cµlture = 20 transformations
• 10mL cµlture = 4 transformations

1. Set up stocks of strains 3-4mL. Grow 30C overnight.
2. In morning, inocµlate 50mL (or 10mL) YPD with 1:50 dilution of stock culture.
3. Incubate cultures 3-4 hours @ 30C (OD600 of 0.5-1.0 = 1-2 X 107)
4. Transfer cultures to falcon tubes.
5. Spin down cells for 2-3 minutes @ 2-3,000 rpm at room temp. Decant.
6. Resuspend in 5mL (2mL) sterile TE. Spin 2-3 min @ 2-3,000 rpm. Decant.
7. Resuspend in 5mL (2mL) LiAc mix. Spin 2 min @ 2-3,000 rpm. Decant.
8. Resuspend in 500µl (100µl) LiAc mix.
9. Add 1.5µl boiled* ssSalmon Sperm DNA (10mg/ml) to eppendorf tube

before using: boil 10m in bead bath, then ice.

1. Add 0.1-5µg DNA to tube (1-2µl miniprep DNA is usually enough)
2. Add 25µl cell suspension to each tube, mix.
3. Add 200µl PEG mix to each tube then vortex.
4. Incubate at least 30 minutes @ 30C.
5. Heat shock 20 minutes @ 42C.
6. To pellet spin 30 seconds.
7. Resuspend in SOS (usually 20µl for plasmids, 200µl for integration).
8. Plate on selective media (streak out 10µl for plasmids, 20µl +180µl for integration).
9. Grow 30C 2-3 days.

Note: cells can be frozen at step 8 in TE + 15% glycerol and stored @ -70C. Thaw slowly, spin down and resuspend in LiAc. However this significantly reduces competence.

PCR

Taq Polymerase/beads

• illustra PuReTaq Ready to Go PCR beads (from GE Healthcare)
• Supplied by Chris Schonbaum

• Each bead is designed for use is a 25μL reaction. When resuspended, each reaction will contain 1.5mM MgCl2.
• Each bead also contains (after final volume)

200μM each dNTP in 10mM Tris-HCl (pH 9 at room temperature)
50μM KCl

• For each bead add

5-25 pmol forward primer
5-25pmol reverse primer
Template DNA (50pg for plasmid DNA, 50ng for complex template such as genomic DNA. Avoid amounts >1μg)

• Snap caps (provided) onto tubes. Mix by gently flicking tubes. Vortex then centrifuge for a few seconds. The reaction is fully dissoluved and mixed when it appears clear.

• For our 50μL reactions we used

2 beads
5μL of each primer (5μM stock, final amount is 25pmol)
.7μL template (plasmid, 30μM)

37.3 μL ddH2O

• Half all amounts for 25μL reactions.

• For cell-culture PCR, we replaced template DNA with a blot of cell culture.