RT-PCR Procedure using frozen cells From Biotechniques:(1996) 21:1094-1100


Stocks:
Freezing Solution
: 0.15 M NaCI + 10 mM Tris, pH 8.0
2x RNase Inhibitor Stock: Add 2 uL of RNase inhibitor to 18 uL of 0.15 M NaCI + 10 mM Tris (pH 8.0) + 5 mM DTT(store at -200C in 10-uL aliquots). (This solution should not be repetitively frozen and thawed see Table 2.)

A-mixture:Pre-mixed, aliquoted and frozen solution that contains all reagents for the RT step except primers. (In this study, RNase inhibitor was deleted from the A-mixture formulation.)

T-mixture:Pre-mixed, aliquoted and frozen solution that contains all reagents for the PCR step except primers.

Primers:100 ng of sense primer and 100 ng of antisense primer/50-uL reaction.

Info on making forzen aliquots for RT and PCR step can be got from Chen.D et al PCR methods Appl. (1993) 2:351-353.

Procedure for a 50-uL RT-PCR:

1.Trypsinize and count cells
2.Add 105 cells to a culture tube and spin at ca. 400x g for 4 mm to gently pellet cells.
3.Resuspend cells in 0.5 mL Freezing Solution to adjust cell concentration to
2x 105 cells/mL.
4.Place 10 uL of resuspended cells in a 0.2-mL microcentrifuge tube and add
10 uL of 2x RNase inhibitor stock. Note: Final cell concentration is now 105 cells/mL
5.Freeze immediately in a pipet tip box (intended for 10-uL tips) containing 95% ethanol chilled to -70 oC. An empty 10-uL pipet tip box will allow a 0.2-mL tube to be about 50% submerged in ethanol.
6.To a new 0.2-mL PCR tube add 3.2 uL A-mixture + 0.5 uL antisense primer (200 nglitL); maintain at 4 oC until cells are added.
7.Thaw cells rapidly in a room temperature water bath, vortex mix for 10s and spin tubes for a few seconds to collect all liquid in the bottom of tubes.
8.Add desired number of cells to tubes. Bring volume to 10 uL with diethylpyrocarbonate-treated water.
9.Place tubes in a PCR thermal cycler preheated to 42 oC; incubate for 1 h to complete the RT step.
10.Add 39 uL of T-mixture and 1 uL of sense primer (100 ng/uL) to perform the PCR step at a 50-uL final volume.
11.Analyze PCR products on a 5% polyacrylamide gel.
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