Somatic cell hybrids were generated by fusion of mouse erythroleukemic cells (clone 745) to mouse lymphoma cells or mouse bone marrow cells. The erythroleukemic cells have been shown previously to have a low basal level of erythroid differentiation which is markedly amplified when the cells are grown in medium containing dimethylsulfoxide (DMSO). Hybrid cells were examined for hemoglobin production by benzidine staining. Many hybrid clones were found in which hemoglobin production in response to DMSO was either abolished or greatly reduced. From these hybrids, subclones were isolated in which hemoglobin production was restored. Karyological and enzyme analysis showed that the restoration of hemoglobin production was associated with the loss of an X chromosome contributed by the nonerythroleukemic parent. Other subclones which retained an X chromosome continued to be inhibited for hemoglobin production. Analysis of other hybrid lines capable of a limited degree of erythroid differentiation indicated a quantitative inverse correlation between the proportion of cells bearing an X chromosome and the proportion of cells able to form hemoglobin. Finally, four hybrid lines having many cells without an X chromosome were grown in medium containing DMSO. This procedure led to the selection of hybrid sublines having a nondifferentiating phenotype and concomitantly having a greatly increased proportion of cells bearing an X chromosome. Thus three lines of evidence suggest that a locus (loci) on the X chromosome is capable of inhibiting the DMSO-inducible hemoglobin production of the erythroleukemic cells.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)