| Start with 15 ml E. coli Culture containing 7.5* 109 cells (OD600= 0.2 Dilute cells or scale up) -
Pipet 30 ml of RNAProtect Bacteria Reagent (Qiagen) into a 50ml polypropylene conical tube. -
Pipet 15 ml culture into the tube. Mix immediately by vortexing for 5second. Incubate for 5min at room temperature. -
Centrifuge for 10min at 5800g( 4500rpm for H-6000A rotor in SORVALL RC-3B centrifuge) -
Decant the supernatant, and leave tubes inverted on a paper towel for 10s. -
Freeze the pellet with EtOH/Dye Ice mix. -
The pellet can be stored at -20°C up to 2 weeks, or -70°C for up to 4 weeks. -
Dilute 2ul of Proteinase K into 300ul of Tissue and Cell Lysis solution for each sample. -
Resuspend cell pellet by the Lysis solution and mix thoroughly. Transfer mix to 1.5ml tube. -
Incubate at 65°C for 45min, and vortex every 15min. -
Place the sample on ice for 5min. -
Add 150ul of MPC protein Precipitation Reagent to 300ul of lysed sample and vortex mix for 10sec. -
Spin for 10min 4°C at max speed in a microcentrifuge. Transfer the supernant to a clean tube. -
Add 50ul of MPC protein Precipitation Reagent and repeat above step. -
Add 500ul isopropanol to the recovered supernatant, invert the tube 30-40 times. -
Pellet the RNA by centrifugation at 4°C for 10min in a microcentrifuge. -
Carefully pour off the isopropanol without dislodging the RNA pellet. Remove all of the residual isopropanol with a pipet. Air dry 10-15min. Removal of contaminating DNA -
Dilute 10ul of RNAse-Free DNAse I up to 200ul with 1x DNAse Buffer for each sample. -
Completely resuspend the nucleic acid pellet in 200ul of DNAse I solution. -
Incubation at 37deg;C for 30min -
Add 200ul of 2x T and C lysis solution, vortex mix for 5 seconds -
Add 200ul of MPC reagent vortex mix 10seconds, place on ice 5min. -
Pellet the debris by centrifugation for 10min at 4°C, 10,000g in a microcentrifuge. -
Add 50ul of MPC reagent and repeat 5 and 6. -
Add 600ul isopropanol to the recovered supernatant, invert the tube 30-40 times. -
Pellet the RNA by centrifugation at 4°C for 10min in a microcentrifuge. -
Carefully pour off the isopropanol without dislodging the RNA pellet. -
Rinse with 75% EtOH (DEPC H2O), being careful to not dislodge the pellet. Centrifuge 5min at 4°C -
Remove all of the residual EtOH with a pipet. Air dry 10-15min. -
Resuspend the nucleic acid in 52ul RNAse-free water. Storage, Quantitation and Determination of Quality of RNA -
Electrophoresis on 1% Agarose gel with 1ul sample. -
Dilute 1ul sample to 100ul with TE(10mM Tris.HCl pH 8, 1mM EDTA), and measure A260 and A280. -
Concentration of RNA sample = 40 x A260 x 100 (Dilution factor) (ug/ml) -
A260/A280 Ratio = A260/A280, ranging from 1.7 to 2.1 -
Add 100ul EtOH and 5ul 3M NaOAC, store at -20°C Note: This protocol was adapted from the original Qiagen and Epicentre protocols. |