Reverse transcriptase-primer extension mix

2.5 ml Tris-Cl (1 M, pH 8.3)

500 μl MnCl₂ (0.1 M)

2 ml actinomycin D (USB 10415; 2.5 mg/ml in H₂O)

132 μl dNTPs (0.1 M mixture of dATP, dGTP, dCTP, and dTTP; Promega U1240)

1 ml DTT (0.5 M)

Add the components in the order given. Add H₂O to bring the final volume to 40 ml. Store in 1-ml aliquots at -20ºC in the dark.