Sodium Chloride → 5'-Thymidylic acid

Participants

Reaction Steps

To 300 μl of a solution comprising 10 mM Tris-HCl (pH 7.5), 6 mM MgCl2 and 10 mM NaCl, there was added 400 μg of pCDV1 [Okayama & Berg: Mol. Cell. Biol., 3, 280 (1983)] and, after further addition of 500 units of KpnI, the reaction was carried out at 37° C. for 6 hours, whereby the plasmid was cleaved at the KpnI site. The DNA recovered by phenol-chloroform extraction followed by ethanol precipitation. About 200 μg of the KpnI-cleaved DNA was added to 200 μl of a solution prepared by adding dTTP in a concentration of 0.25 mM to TdT buffer and, after further addition of 81 units of TdT (P-L Biochemicals), the reaction was carried out at 37° C. for 11 minutes, whereby a poly(dT) chain (about 67 dT residues) was added to each 3' end of the KpnI cleavage site of pCDV1. About 100 μg of the poly(dT) chain tailed pCDV1 DNA was recovered from the solution by ethanol precipitation following phenol-chloroform extraction. The DNA was added to 150 μl of a solution comprising 10 mM Tris-HCl (pH 7.5), 6 mM MgCl2 and 100 mM NaCl and, after further addition of 360 units of EcoRI, the reaction was carried out at 37° C. for 2 hours. The reaction mixture was treated by the LGT method, and a DNA fragment of about 3.1 kb was recovered. About 60 μg of the poly(dT) chain-tailed pCDV1 was thus obtained. The DNA was dissolved in and 1 mM EDTA, the solution was incubated at 65° C. for 5 minutes and then cooled with ice, and 50 μl of 5 M NaCl was added. The mixture was subjected to oligo(dA)-cellulose column (Collaborative Research) chromatography. Molecules having a sufficient poly(dT) chain length were adsorbed on the column and they were eluted with a solution comprising 10 mM Tris-HCl (pH 8.0) and 1 mM EDTA to give 27 μg of the poly(dT) chain-tailed pCDV1 (hereinafter referred to as vector primer).

Provenance & Evidence