Established from Human -Globin Locus Yeast Artificial

Identification of trans-acting factors or drugs capable of reacti-vating -globin gene expression is complicated by the lack of suita-ble cell lines. Human K562 cells co-express - and -globin but not -globin; transgenic mouse erythroleukemia 585 cells express pre-dominantly human -globin but also -globin; and transgenic murine GM979 cells co-express human -and -globin. Human -globin locus yeast artificial chromosome transgenic mice display correct developmental regulation of -like globin gene expression. We rationalized that cells established from the adult bone marrow of these mice might express exclusively -globin and therefore could be employed to select or screen inducers of -globin expres-sion. A thrombopoietin receptor derivative that brings the prolifer-ative status of primary mouse bone marrow cells under control of a chemical inducer of dimerization was employed to institute and maintain these cell populations. Human -globin was expressed