ACTIVE EXPRESSION OF G-GAMMA GLOBIN GENE ON CHROMOSOME-11 WITH YUNNANESE (A-GAMMA-DELTA-BETA)DEGREES-THALASSEMIA DELETION IN MEL CELLS

A permanent lymphocyte cell line of a heterozygote with Yunnanese (A g amma delta beta)(0)-thalassemia deletion, associated with an increased production of G gamma globin in adult, was founded using Epstein-Barr virus transformation. The hybrids of the lymphocyte cell and mouse er ythroleukemia cell (MEL) were achieved and the hybrids containing huma n chromosome 11 were selected with the monoclonal antibody 53/6. The s ubclones containing only either the normal or the abnormal human chrom osome 11 were separated and the expression of the human globin genes w as studied. Expression of the beta-globin gene, but not the G gamma an d A gamma, was observed in the hybrids containing only the normal huma n chromosome 11, while active expression of the G gamma globin gene wa s observed in the hybrids containing only the abnormal human chromosom e 11. These results have confirmed that the DNA deletion in the beta-g lobin gene cluster is the cause of persistent active expression of the G gamma globin gene in the Yunnanese mutant.