DIFFERENTIAL EXPRESSION OF THE GLOBIN GENES IN HUMAN LEUKEMIA-K562(S) CELLS INDUCED TO DIFFERENTIATE BY HEMIN OR BUTYRIC-ACID

  • 1 January 1981
    • journal article
    • research article
    • Vol. 41  (1) , 237-243
Abstract
Human leukemia K562(S) cells were induced to differentiate by 50 .mu.M hemin or 1.4 mM butyric acid, and the types of Hb synthesized were compared. Butyric acid-treated K562(S) cells contained mostly Hb Gower 1 (.zeta.2.epsilon.2) and a Hb with the electrophoretic characteristics of Portland (.gamma.2.zeta.2). For hemin-treated K562(S), the most abundant Hb synthesized was Hb X (.zeta.2.gamma.2), followed by Bart''s (.gamma.4). Traces of Gower 1 were observed in nontreated K562(S) cells. Increased Hb synthesis was detected after only 24 h of hemin treatment, whereas 4 days were required in butyric acid-treated cells. Hemin and butyric acid were able to induce their respective patterns of Hb synthesis independent of the presence of serum in the K562(S) growth medium. With both inducers, adult .alpha.-, but not .beta.-globin chains, were present. Karyotype analysis of K562(S) cells revealed a nearly triploid chromosome complement with a modal number of 68 chromosomes. Three copies of chromosome 11, and 4 copies of chromosome 16 (coding for the .beta.-like and .alpha.-like globin genes, respectively) were present. A large marker chromosome, involving chromosome 7, and a Philadelphia chromosome were also seen.