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Ca PO4, Transfection
(106 mm plates)
1. Remove old media from plates and add 10 mls fresh
2. Add 1/2 ml 2 X CaCl2 to 15 ml tube (can double reactions if desired)
3. Add 20 - 30 ug DNA to each tube
-optimal amount of DNA will vary with @ DNA prep.
-DNA should be very pure
-can use carrier DNA if specific DNA is limiting
ex: 20 ug calf thymus DNA (optimized to 25 ug) 5 ug SV2 CAT DNA
4. Add 1/2 ml 2 X BBS to each tube dropwise
-let each drop slowly down tube into CaCl2-DNA solution
5. Tap gently & let stand at R.T. 5-101
6. Add 1 ml mixtures to each plate of cells and put cells at 350C,
3.5% C02 - O.N.
7. Next day should have very fine pcpt. coverning bottom of plate
8. Wash cells 3 X w/serum free media
-for each wash leave media on cells for 1-51 before replacing
9. Add 10 mls fresh media w/serum and put at 370, 6% C02 until
ready to harvest
20 X CaCl.
2. 5 M CaCl2 in H20
18.3 g CaCl2 qs=50 ml
" X BBS
50 mM BES (KW 213) sigma Cat. #B-9879 10.65g
280 mM NACL 16.464g 1.5 nl4 Na2HP04 213mg
pH to 6.89 w/NaOH qs=l liter
10. Harvest the cells 48 hours after transfecting them. Aspirate media, and wash 2 times with PBS. Add 1 ml cold TEN buf f er and let set for 5 minutes. Remove cells with a rubber policeman or cell scraper, and transfer to Eppendorf tubes. Spin 5 min. in a microfuge. Aspirate the buffer, and add 150 ul (300 ul for 100 mm plates) cold 0.25 M TRIS, pH 7.8. Sonicate cells with 6-1 sec. bursts. Spin for 5 min. again in a microfuge. The size of the cell pellet should be smaller than after
spinning the whole cells. Transfer the supernatant to
Eppendorf tubes and store frozen at -200C.
11. CAT Assav Add .25 M TRIS to Eppendorf tubes so that the final volume of buffer plus cell extract will be 150 ul. Then add: 25 ul Acetyl Co-A (Lithium salt, from PL Biochemicals), 3.52 mg/ml 5 ul 14 C-Chloramphenicol (NEN) cell extract.
Vortex, and incubate for 60 min. at 370
Stop the reaction by extracting 2 X with 1 ml ethyl acetate.
Dry the extract, then resuspend in 30 ul ethyl acetate. Spot 10 ul onto TLC plates. Chromatograph in 200 ml of 95:5 chloroform: methanol (takes about 1.5-2 hrs.)
Expose to X-ray film O.N. at room temperature.
TEN Buffer
.4 ml TRIS pH 7.5 (lM) .2 ml EDTA (.5M) 3 ml NaCl (5M) 92.5 ml H20
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