Abstract
Murine erythroleukemia cells are useful for studying the regulation of erythroid differentiation since these malignant pronormoblasts differentiate to orthochromatic normoblasts when treated with a variety of inducing agents. Changes in chromatin proteins have been described following inducer exposure. The significance of these changes, which are greatest in terminally differentiated cells remains unknown. Ubiquitin is a highly conserved 8.5 kilodalton peptide that is covalently linked to up to 10% of histone H2A. We demonstrate that following exposure of MEL cells to inducers of differentiation, a transient increase in ubiquitination of H2A occurs. This change is coincident with the onset of differentiation. This result suggests that ubiquitination of H2A may have a role in the nuclear changes necessary for erythroleukemic cell differentiation.
