E2A-PBX1 Interacts Directly with the KIX Domain of CBP/p300 in the Induction of Proliferation in Primary Hematopoietic Cells

Abstract

The E2A gene encodes DNA-binding transcription factors, called E12 and E47, involved in cell specification and maturation. E2A is also involved in a chromosomal translocation that leads to the expression of an oncogenic transcription factor called E2A-PBX1 in cases of acute leukemia. In the work described here, we elucidate the interaction between E2A-PBX1 and transcriptional co-activators. We confirm that the E2A portion can interact with CBP and PCAF and map required elements on E2A and CBP. On CBP, the interaction involves the KIX domain, a well characterized domain that mediates interactions with several other oncogenic transcription factors. On E2A, the interaction with CBP requires conserved ␣-helical domains that reside within activation domains 1 and 2 (AD1 and AD2, respectively). Using purified, recombinant proteins, we show that the E2A-CBP interaction is direct. Notwithstanding the previously demonstrated ability of AD1 and AD2 to function independently, some of our findings suggest functional cooperativity between these two domains. Finally, we show that the CBP/p300-interactive helical domains of E2A are important in the induction of proliferation in cultured primary bone marrow cells retrovirally transduced with E2A-PBX1. Our findings suggest that some aspects of E2A-PBX1 oncogenesis involve a direct interaction with the KIX domain of CBP/p300.

Human T-Cell Leukemia Virus Type 1 Tax Protein Down-Regulates Pre-T-Cell Receptor Alpha Gene Transcription in Human Immature Thymocytes

“…These observations are in line with previous results, showing that the interaction of Tax with p300 represses the transcriptional activity of bHLH proteins (33,38). It has been reported that Tax binds to the KIX domain of p300, with which E2A interacts directly (2,15,33). Interestingly, we have observed that cotransfection of a plasmid encompassing this region is also able to restore the activation of the pT␣ promoter (data not shown).…”

“…Thus, Id proteins block the transcriptional activity of the E proteins by sequestering them away from the E-boxes (3). Finally, E proteins, like other bHLH proteins, have been shown to bind to the p300/CREB binding protein (CBP) coactivators (2,16,34).…”

Molecular functions of the transcription factors E2A and E2-2 in controlling germinal center B cell and plasma cell development

“…Moreover, few repressed target genes were highly regulated by the two E-proteins in contrast to a large proportion of the activated target genes. In support of transcriptional activation, E-proteins contain 3 activation domains (AD1, AD2, and AD3), which interact with the coactivators p300 and CBP (Bradney et al, 2003;Bayly et al, 2004) and the promoter recognition factor TFI ID (Chen et al, 2013). At the chromatin level, we identified a novel role for E-proteins in shaping the enhancer landscape at its activated target genes, as E2A and E2-2 are responsible for the induction and maintenance of DHS sites containing E2A-binding sites.…”

“…Within the lymphoid system, E-proteins function as homodimers or heterodimers with a different E-protein (Bain et al, 1993;Shen and Kadesch, 1995). E-proteins are thought to mainly function as transcriptional activators, as they interact with the co-activators p300 and CBP (Bradney et al, 2003;Bayly et al, 2004), as well as the promoter recognition factor TFI ID (Chen et al, 2013). The activity of E-proteins is controlled by the inhibitor of DNA binding proteins, which are HLH proteins lacking the basic DNA-binding domain, and are thus capable of sequestering E-proteins into DNA-bindingincompetent heterodimers (Kee, 2009).…”

Detecting reliable gene interactions by a hierarchy of Bayesian network classifiers

“…Lee et al [50] describes a physiological regulation of [beta]-catenin stability by TCF3 and CKlepsilon. Moreover, another of the reported genes, CBFB encodes a protein that belongs to the beta subunit of a heterodimeric core-binding transcription factor belonging to the PEBP2/CBF transcription factor family which master-regulates a host of genes specific to hematopoiesis [51](e.g. RUNX1) and osteogenesis (e.g.…”