Induction of Ubiquitin-Conjugating Enzymes During Terminal Erythroid Differentiation

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 92; no. 11; pp. 4982 - 4986
• Main Authors: Wefes, Inge, Mastrandrea, Lucy D., Haldeman, Margaret, Koury, Stephen T., Tamburlin, Judith, Pickart, Cecile M., Finley, Daniel
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 23.05.1995; National Acad Sciences; National Academy of Sciences
• Subjects: Amino Acid Sequence; Animals; Antibodies; Biology; Cattle; Cell Differentiation; Cellular differentiation; Chromatography, Ion Exchange; Complementary DNA; Deoxyribonucleic acid; DNA; Electrophoresis, Polyacrylamide Gel; Enzyme Induction; Enzymes; Epics; Erythroblasts - cytology; Erythroblasts - enzymology; Erythrocytes; Erythroid cells; Erythropoiesis; Female; Genes; Immunoblotting; Isoenzymes - biosynthesis; Isoenzymes - isolation & purification; Ligases - biosynthesis; Ligases - blood; Ligases - isolation & purification; Male; Mice; Mice, Inbred Strains; Molecular Sequence Data; Organ Specificity; Peptides - chemical synthesis; Peptides - immunology; Phenylhydrazines; Proteins; Rabbits; Recombinant Proteins - biosynthesis; Recombinant Proteins - isolation & purification; Reticulocytes; Reticulocytes - cytology; Reticulocytes - enzymology; Transcription, Genetic; Ubiquitin-Conjugating Enzymes; Ubiquitins; Ubiquitins - metabolism
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.92.11.4982

A global cellular reorganization occurs during the reticulocyte stage of erythroid differentiation. This reorganization is accomplished partly through programmed protein degradation. The selection of proteins for degradation can be mediated by covalent attachment of ubiquitin. We have cloned cDNAs encoding two ubiquitin-conjugating (E2) enzymes, E2-20K and E2-230K, and found their genes to be strongly induced during the differentiation of erythroblasts into reticulocytes. Induction of the E2-20K and E2-230K genes is specific, as transcript levels for at least two other ubiquitinating enzymes fall during erythroblast differentiation. In contrast to most proteins induced in reticulocytes, E2-20K and E2-230K enzymes are present at strongly reduced levels in erythrocytes and thus decline in abundance as reticulocyte maturation is completed. This result suggests that both enzymes function during the reticulocyte stage, when enhanced protein degradation has been observed. These data implicate regulated components of the ubiquitin conjugation machinery in erythroid differentiation.