Selective Expression Within the Human Alpha Globin Gene Complex Following Chromosome-dependent Transfer into Diploid Mouse Erythroleukaemia Cells

Human chromosome 16, which contains the alpha globin gene complex, has been introduced into mouse erythroleukaemia cells by means of cell fusion and selectively retained to the exclusion of other human chromosomes. After induction of haemoglobin synthesis in hybrid clones, evidence for expression of the human alpha globin genes was sought by mRNA and globin chain synthesis analyses. It was found that both the human alpha 1 and alpha 2 genes were similarly expressed and that the synthesis of human alpha globin chains was nearly half that of mouse alpha chains on a per gene basis. The pattern of human alpha gene expression was similar with different inducers and with donor chromosomes of either erythroid or non-erythroid origin. However, the closely linked human embryonic alpha gene (zeta) did not produce detectable levels of zeta globin mRNA in any of the hybrid clones. Thus, there is selective activation of adult genes in the human alpha globin gene complex in the mouse erythroleukaemia cell.