Physical interaction between retinoic acid receptor and the oncoprotein Myb inhibits retinoic acid-dependent transactivation

Edith Pfitzner, Jutta Kirfel, Peter Becker, Andreas Rolke, Roland Schüle*

*Corresponding author for this work
28 Citations (Scopus)


The c-myb protooncogene is predominantly expressed in hematopoietic cells and plays a vital role in hematopoiesis. Retinoic acid (RA) is able to induce differentiation of several hematopoietic cells. This differentiation is linked to decreased c-myb expression, suggesting that retinoid receptors (RAR/RXR) may down-regulate c-myb gene expression. Furthermore, recent data indicate that RAR inhibits the function of the Myb protein itself. In addition, the Myb-Ets oncogenic fusion protein has been shown to inhibit transcriptional activation by RAR and thyroid hormone receptor. Myb-Ets also antagonizes the biological response of erythrocytic progenitor cells to RA and thyroid hormone. This prompted us to investigate a possible cross talk between RAR and Myb. Here, we demonstrate that RA inhibits the expression of the endogenous Myb target gene tom-1. Conversely, Myb functions as a potent inhibitor of RA-induced biological responses. Functional analysis of Myb mutants in transfection studies revealed that the Myb DNA-binding domain (DBD) is necessary for repression whereas the transactivation domain is dispensable. Furthermore, we show that v-Myb and RAR interact in vitro and in vivo. This interaction requires the DBD of RAR. In contrast, glutathione S- transferase-pulldown assays with v-Myb mutants indicate that the DBD and the C terminus of Myb directly interact with RAR. Our results suggest that the physical interaction between Myb and RAR may play a role in the regulation of hematopoietic gene expression.

Original languageEnglish
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number10
Pages (from-to)5539-5544
Number of pages6
Publication statusPublished - 12.05.1998


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