Cooperative interaction of Ets-1 with USF-1 required for HIV-1 enhancer activity in T cells

Sieweke, Michael H.; Tekotte, Hille; Jarosch, Ursula; Graf, Thomas

doi:10.1093/emboj/17.6.1728

Cited by 125 publications

(106 citation statements)

References 57 publications

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“…This is supported by the finding that phosphorylation of Sp1 and PU.1 are increased as myeloid cells differentiate (52,59). A second mechanism suggested by Sieweke et al (56) suggests that ets-1 and USF-1 interact to form a complex, resulting in exposure of the respective DNA-binding domains of each factor. According to both of these models a ternary complex would exist that should be detectable by EMSA.…”

Section: Discussionmentioning

confidence: 82%

“…Although these factors are ubiquitously expressed, an increasing number of studies have appeared in the past several years demonstrating a role for USF in the regulation of tissue-specific genes. USF binding has been shown to be required for human immunodeficiency virus type-1 enhancer activity in T cells (56) and for regulation of expression of the surfactant protein-A gene (57). Involvement of USF in myeloid cell differentiation was suggested by Kreider et al (58) and Suzow and Friedman (25) reported that deletion of the E box in the myeloperoxidase gene reduced promoter activity by 5-fold.…”

Section: Discussionmentioning

confidence: 95%

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PU.1 and USF Are Required for Macrophage-specific Mannose Receptor Promoter Activity

Egan¹,

Lane²,

Shepherd

1999

Journal of Biological Chemistry

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In the current study we report the isolation of 854 base pairs of the rat mannose receptor promoter. Analysis of the sequence revealed one Sp1 site, three PU.1 sites, and a potential TATA box (TTTAAA) 33 base pairs 5 of the transcriptional start site. The tissue specificity of the promoter was determined using transient transfections. The promoter was most active in the mature macrophage cell line NR8383 although the promoter also showed activity in the monocytic cell line RAW. No activity was observed in pre-monocytic cell lines or epithelial cell lines. Mutation of the TTTAAA sequence to TTGGAA resulted in a 50% decrease in activity in transient transfection assays suggesting that the promoter contains a functional TATA box. Using electrophoretic mobility shift assays and mutagenesis we established that the transcription factors Sp1, PU.1, and USF bound to the mannose receptor promoter, but only PU.1 and USF contributed to activation. Transient transfections using a dominant negative construct of USF resulted in a 50% decrease in mannose receptor promoter activity, further establishing the role of USF in activating the rat mannose receptor promoter. Comparison of the rat, mouse, and human sequence demonstrated that some binding sites are not conserved. Gel shifts were performed to investigate differences in protein binding between species. USF bound to the rat and human promoter but not to the mouse promoter, suggesting that different mechanisms are involved in regulation of mannose receptor expression in these species. From these results we conclude that, similar to other myeloid promoters, transcription of the rat mannose receptor is regulated by binding of PU.1 and a ubiquitous factor at an adjacent site. However, unlike other myeloid promoters, we have identified USF as the ubiquitous factor, and demonstrated that the promoter contains a functional TATA box.

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Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 95%

PU.1 and USF Are Required for Macrophage-specific Mannose Receptor Promoter Activity

Egan¹,

Lane²,

Shepherd

1999

Journal of Biological Chemistry

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“…For example, interaction between Ets1 and USF-1 results in cooperative activation of the human immunodeficiency virus, type I, promoter. The consensus site for USF-1 and the transcriptional activation domain of Ets1 are both required for this effect, whereas a functional ETS-binding site is not (22). Thus ETS proteins can be recruited to promoters and contribute to transcriptional regulation without directly binding to DNA.…”

Section: Discussionmentioning

confidence: 99%

DNA Binding Domain-independent Pathways Are Involved in EWS/FLI1-mediated Oncogenesis

Welford¹,

Hebert²,

Deneen³

et al. 2001

Journal of Biological Chemistry

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Specific chromosomal translocations involving the ews gene and one of five members of the ets family of transcription factors create ews/ets fusion genes that are found in ϳ85% of Ewing's family of tumors. ews/ets fusion genes consistently maintain an intact and functional ets DNA binding domain (DBD) in all of these cases. We demonstrate here, however, that EWS/FLI1, the most prevalent EWS/ETS fusion, activates oncogenic pathways independent of its DBD. In in vivo tumor assays, EWS/FLI1 molecules with either point mutations or a large deletion in the ets DBD retain the ability to accelerate tumors in NIH 3T3 cells, whereas they lose the ability to bind DNA in vitro. Additionally, whereas inhibition of DBD functions of EWS/FLI1 with a dominant negative form of FLI1 is sufficient to inhibit anchorage-independent growth in NIH 3T3 cells, it is ineffective in inhibiting tumor growth in SCID mice. Usage of this dominant negative construct in a Ewing's tumor cell line, however, does reduce the rate of tumor formation, supporting the need for a functional DBD in this context. Together, these results suggest that EWS/FLI1 induces both DBD-dependent and DBD-independent oncogenic pathways.The production of chimeric fusion genes through chromosomal translocation is a common theme in the development of neoplasia. The resultant gene products often utilize domainassociated functions derived from the native participants of the fusions but in novel, atypical contexts. Such is the case for the Ewing's family of tumors, in which the ews gene on chromosome 22 is fused to one of five members of the ets family of transcription factors (FLI1, ERG, ETV1, E1AF, or FEV) (1). The consequent ews/ets fusion genes are thought to utilize amino-terminal EWS transactivation domains and intact carboxyl-terminal ets DNA binding domains (DBDs) 1 to form aberrant transcription factors that induce neoplastic phenotypes through altered gene regulation (2).EWS is a member of the TET family of RNA-binding proteins, which also includes TLS and TAF II 68 (3). These genes are commonly involved in chromosomal translocations that lead to the development of cancer, particularly sarcomas. In addition to Ewing's sarcoma, TET translocations are associated with at least five other sarcomas including desmoplastic small round cell tumors, clear cell sarcoma, and myxoid liposarcoma (1). A pervasive feature of all of the TET translocations is that a TET family member is fused to an intact DBD of a transcription factor. This observation supports the hypothesis that TET translocation products, including EWS/ETS fusions, utilize their DBDs to bind DNA and directly alter transcriptional activity.Although the physiological functions of wild type EWS are not well defined, EWS may have a role in coupling transcription and RNA processing. The amino-terminal transcriptional activation domain of EWS includes protein-protein interaction domains that direct binding to RNA polymerase II subunits (4, 5). In addition, an interaction with splicing factor U1C has been mapped to ...

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“…Some of these factors are induced by CD28 signaling, and can bind sites within the HIV-1 long terminal repeat (LTR) and activate HIV-1 transcription (29,(32)(33)(34). Furthermore, the viral transcriptional trans activator Tat is necessary for efficient transcription.…”

Section: P Roductive Infection Of Cd4mentioning

confidence: 99%

Recruitment of Phosphatidylinositol 3-Kinase to CD28 Inhibits HIV Transcription by a Tat-Dependent Mechanism

Cook¹,

August

Henderson

2002

The Journal of Immunology

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Activation through the TCR and the costimulatory molecule CD28 influences the susceptibility of T cells to HIV-1 infection and regulates proviral gene expression. Signaling events initiated by CD28 that directly impact HIV-1 transcription have not been fully characterized. T cell lines expressing CD8α/28 chimeric receptors containing a mutation in tyrosine 173 to phenylalanine, which inhibits the recruitment of phosphatidylinositol 3-kinase (PI3K) to CD28, expressed higher levels of HIV-1 following T cell activation. Whereas constitutively active PI3K decreased provirus transcription, inhibiting endogenous PI3K with specific inhibitors or by overexpressing PTEN phosphatase enhanced HIV-1 expression. PI3K-dependent inhibition required the viral Tat protein and a trans activation response region element. Tat pull-down and coimmunoprecipitation experiments indicate that PI3K affects the formation of the Tat-associated kinase trans-activating complex. These studies demonstrate that PI3K negatively impacts HIV-1 transcription and that Tat activity is sensitive to T cell signaling events.

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Cooperative interaction of Ets-1 with USF-1 required for HIV-1 enhancer activity in T cells

Cited by 125 publications

References 57 publications

PU.1 and USF Are Required for Macrophage-specific Mannose Receptor Promoter Activity

PU.1 and USF Are Required for Macrophage-specific Mannose Receptor Promoter Activity

DNA Binding Domain-independent Pathways Are Involved in EWS/FLI1-mediated Oncogenesis

Recruitment of Phosphatidylinositol 3-Kinase to CD28 Inhibits HIV Transcription by a Tat-Dependent Mechanism

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