A transient increase in histone H2A ubiquitination is coincident with the onset of erythroleukemic cell differentiation

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.