Open AccessChemical Mutagenesis at the Phosphoribosyltransferase Locus in Cultured Human Lymphoblasts
Author(s) -
Koki Sato,
R.S. Slesinski,
John W. Littlefield
Publication year - 1972
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.69.5.1244
Subject(s) - phosphoribosyltransferase , hypoxanthine guanine phosphoribosyltransferase , lymphoblast , mutant , adenine phosphoribosyltransferase , microbiology and biotechnology , mutagenesis , biology , biochemistry , chemistry , cell culture , genetics , enzyme , gene , purine
The presence of selectable genetic markers in long-term human lymphoblast cultures would facilitate cell hybridization experiments on the biosynthesis of immunoglobulins, as well as other studies. This work reports the induction with ethylmethane sulfonate of 6-thioguanine - resistant, phosphoribosyltransferase - deficient mutants in a lymphoblast line from a patient with infectious mononucleosis. These cells were unusually sensitive, with a D0 value of 28 μg of ethylmethane sulfonate per ml; the sensitivity curve followed a biphasic pattern suggesting the presence of 3% resistant cells. Ethylmethane sulfonate increased the frequency of mutants resistant to 6-thioguanine over 100-fold, to about 2 × 10-4 ; nitrosoguanidine was less effective. Almost all the mutants contained considerably less than 1% of the hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) activity of wild-type cells. The mutation did not appear to result from loss of an X chromosome.