Incorporation of deoxynucleotides into DNA by diethylaminoethyldextran-treated lymphocytes

In the presence of diethylaminoethyldextran cultured human lymphocytes will utilize deoxynucleotides for the synthesis of DNA, whereas in the absence of diethylaminoethyldextran no incorporation of deoxynucleotides is detected. Labeled deoxynucleoside mono-, di-, and triphosphates are incorporated into DNA at approximately the same rate. Deoxynucleotide incorporation is essentially linear for 10 min but continues at a gradually diminishing rate for an additional 20 to 50 min. The initial rate of DNA synthesis is at least 20 to 40% of the in vivo rate, and in those cells that are in S phase 0.7-1.5% of the DNA is synthesized. By the three properties examined (restriction to S phase, semiconservative mode, and initial product in short chains), DNA synthesis in diethylaminoethyldextran-treated cells resembles DNA synthesis in vivo.