{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T16:58:02Z","timestamp":1781110682915,"version":"3.54.1"},"reference-count":0,"publisher":"National Academy of Sciences","issue":"5","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[1972,5]]},"abstract":"<jats:p>\n                    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 D\n                    <jats:sub>0<\/jats:sub>\n                    value of 28 \u03bcg 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 \u00d7 10\n                    <jats:sup>-4<\/jats:sup>\n                    ; 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.\n                  <\/jats:p>","DOI":"10.1073\/pnas.69.5.1244","type":"journal-article","created":{"date-parts":[[2006,5,31]],"date-time":"2006-05-31T02:35:42Z","timestamp":1149042942000},"page":"1244-1248","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":81,"title":["Chemical Mutagenesis at the Phosphoribosyltransferase Locus in Cultured Human Lymphoblasts"],"prefix":"10.1073","volume":"69","author":[{"given":"Koki","family":"Sato","sequence":"first","affiliation":[{"name":"Genetics Unit, Children's Service, Massachusetts General Hospital, Boston, Mass. 02114"},{"name":"Department of Pediatrics, Harvard Medical School, Boston, Mass. 02114"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ronald S.","family":"Slesinski","sequence":"additional","affiliation":[{"name":"Genetics Unit, Children's Service, Massachusetts General Hospital, Boston, Mass. 02114"},{"name":"Department of Pediatrics, Harvard Medical School, Boston, Mass. 02114"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John W.","family":"Littlefield","sequence":"additional","affiliation":[{"name":"Genetics Unit, Children's Service, Massachusetts General Hospital, Boston, Mass. 02114"},{"name":"Department of Pediatrics, Harvard Medical School, Boston, Mass. 02114"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[1972,5]]},"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.69.5.1244","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T10:34:38Z","timestamp":1649846078000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.69.5.1244"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1972,5]]},"references-count":0,"journal-issue":{"issue":"5","published-print":{"date-parts":[[1972,5]]}},"alternative-id":["10.1073\/pnas.69.5.1244"],"URL":"https:\/\/doi.org\/10.1073\/pnas.69.5.1244","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[1972,5]]},"assertion":[{"value":"1972-05-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}