Rat9G cells are grown on microscope slides and immediate early HCMV mRNA expression is induced (in approximately 30% of the cells) by incubating cells with cycloheximide for 4-6 hours. After this:
- Wash cells shortly with PBS;
- Fix cells in 4% formaldehyde/5% acetic acid in PBS for 15 min;
- Wash cells 2 x 5 min with PBS;
- Treat cells with pepsin (0.1% in 10 mM HCl) for 1 min at 37ºC;
- Wash cells 2 times shortly with water;
- Dehydrate through 70%-, 90%- and 100% ethanol;
- Air dry.
- Put 10 μl of diluted probe (see below) on a slide and cover with a 18x18 mm
cover slip;
- Denature probe + slide at 80ºC for 75 sec;
- Hybridize for 30 min at 37ºC in a moist chamber;
- Wash off the cover slip by immersion in 2xSSC, 0.1% Tween-20;
- Wash 3 x 5 min with 0.1xSSC at 65ºC;
- Dehydrate through 70%-, 90%- and 100% ethanol;
- Air dry;
- Bring on 20 μl of DAPI + antifade and cover with a 24x50 mm coverslip.