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Sp3 is a member of the Sp family of transcription factors and binds to DNA with affinity and specificity comparable to that of Sp1. We demonstrate that Sp3 is a bifunctional transcription factor that can both activate and repress transcription. Gene fusion experiments in mammalian cells demonstrate that the Sp3 activation potential is distributed over an(More)
Sp1 is one of the very first cellular transcription factors to be identified and cloned in virtue of its binding to a G-rich motif in the SV40 early promoter. Sp1 protein binds to the G-rich sequences present in a variety of cellular and viral promoters and stimulates their transcriptional activity. Recently, a number of other GC and/or GT box-binding(More)
RAR and AML1 transcription factors are found in leukemias as fusion proteins with PML and ETO, respectively. Association of PML-RAR and AML1-ETO with the nuclear corepressor (N-CoR)/histone deacetylase (HDAC) complex is required to block hematopoietic differentiation. We show that PML-RAR and AML1-ETO exist in vivo within high molecular weight (HMW) nuclear(More)
The class A of basic helix-loop-helix (bHLH) proteins are ubiquitously expressed transcription factors playing a pivotal role in the regulation of cell growth and differentiation. We determined that enforced expression of all four different mammalian members of this family, E12, E47, E2-2, and HEB, suppresses the cell colony-forming efficiency of several(More)
While much experimental data shows that vaccination efficiently inhibits a subsequent challenge by a transplantable tumor, its ability to inhibit the progress of autochthonous preneoplastic lesions is virtually unknown. In this article, we show that a combined DNA and cell vaccine persistently inhibits such lesions in a murine HER-2/neu mammary(More)
The urokinase-type plasminogen activator receptor (uPAR) focuses at the cell surface the activation of pro-uPA and, hence, the formation of plasmin, thus enhancing directional extracellular proteolysis. To characterize the transcriptional regulatory mechanisms that control receptor expression, we have cloned an uPAR DNA segment containing upstream(More)
Mammalian homologues of Drosophila Seven in Absentia (SIAHs) target for proteasome-mediated degradation several factors involved in cell growth and tumorigenesis. Here we show that SIAH-1/2 binds and targets for proteasome-mediated degradation the putative tumor suppressor and tripartite motif (TRIM) family member PML, leading to the loss of its(More)
An increasing body of evidence suggests that eukaryotic activators stimulate polymerase II transcription by facilitating the assembly of the functional basal machinery at the promoter. Here we describe experiments that provide added support for the idea that recruitment of TATA-binding protein (TBP) is a rate-limiting step for transcription activation in(More)
Here we investigated mechanisms underlying the acclimation to light in the marine angiosperm Posidonia oceanica, along its bathymetric distribution (at -5 m and -25 m), combining molecular and photo-physiological approaches. Analyses were performed during two seasons, summer and autumn, in a meadow located in the Island of Ischia (Gulf of Naples, Italy),(More)
Recently, a family of transcription factors structurally related to Sp1 has been described; thus, more than one activator may bind to the GC boxes present in a number of viral and cellular promoters. We have compared the transactivation potentials of Sp1, Sp3 and Sp4 proteins on the human immunodeficiency virus type 1 (HIV-1) promoter. The long terminal(More)