Activation of the Snail transcription factor induces Mdm2 gene expression.

Epithelial-like tumor cells can become metastatic by undergoing molecular and phenotypic reprogramming in a process referred to as epithelial-to-mesenchymal transition (EMT). In response to EMT genes that promote migration and condition the tumor microenvironment to permit intravasation into the bloodstream, dissemination and extravasation into new organs are induced. While the mutant p53 has been implicated in extravasation, one negative regulator of p53, the oncogene murine double minute-2 gene (Mdm2), is required in the early stages of metastasis and the driver of EMT.

Pharmacologic targeting of the p62 ZZ domain enhances both anti-tumor and bone-anabolic effects of bortezomib in multiple myeloma.

Multiple myeloma (MM) is a malignancy of plasma cells whose antibody secretion creates proteotoxic stress relieved by the N-end rule pathway, a proteolytic system that degrades N-arginylated proteins in the proteasome. When the proteasome is inhibited, protein cargo is alternatively targeted for autophagic degradation by binding to the ZZ-domain of p62/ sequestosome-1. Here, we demonstrate that XRK3F2, a selective ligand for the ZZ-domain, dramatically improved two major responses to the proteasome inhibitor bortezomib (Btz) by increasing: i) killing of human MM cells by stimulating both Btz-mediated apoptosis and necroptosis, a process regulated by p62; and ii) preservation of bone mass by stimulating osteoblast differentiation and inhibiting osteoclastic bone destruction.

Direct Detection of Isolevuglandins in Tissues using a D11 scFv-Alkaline Phosphatase Fusion Protein and Immunofluorescence.

Isolevuglandins (IsoLGs) are highly reactive gamma ketoaldehydes formed from H2-isoprostanes through lipid peroxidation and crosslink proteins leading to inflammation and various diseases including hypertension. Detection of IsoLG accumulation in tissues is crucial in shedding light on their involvement in the disease processes. However, measurement of IsoLGs in tissues is extremely difficult, and currently available tools, including mass spectrometry analysis, are laborious and extremely expensive.

LMO2 Oncoprotein Stability in T-Cell Leukemia Requires Direct LDB1 Binding.

LMO2 is a component of multisubunit DNA-binding transcription factor complexes that regulate gene expression in hematopoietic stem and progenitor cell development. Enforced expression of LMO2 causes leukemia by inducing hematopoietic stem cell-like features in T-cell progenitor cells, but the biochemical mechanisms of LMO2 function have not been fully elucidated. In this study, we systematically dissected the LMO2/LDB1-binding interface to investigate the role of this interaction in T-cell leukemia.

Hhex is Required at Multiple Stages of Adult Hematopoietic Stem and Progenitor Cell Differentiation.

Hhex encodes a homeodomain transcription factor that is widely expressed in hematopoietic stem and progenitor cell populations. Its enforced expression induces T-cell leukemia and we have implicated it as an important oncogene in early T-cell precursor leukemias where it is immediately downstream of an LMO2-associated protein complex. Conventional Hhex knockouts cause embryonic lethality precluding analysis of adult hematopoiesis.

Direct TFIIA-TFIID protein contacts drive budding yeast ribosomal protein gene transcription.

We have previously shown that yeast TFIID provides coactivator function on the promoters of ribosomal protein-encoding genes (RPGs) by making direct contact with the transactivator repressor activator protein 1 (Rap1). Further, our structural studies of assemblies generated with purified Rap1, TFIID, and TFIIA on RPG enhancer-promoter DNA indicate that Rap1-TFIID interaction induces dramatic conformational rearrangements of enhancer-promoter DNA and TFIID-bound TFIIA. These data indicate a previously unknown yet critical role for yeast TFIIA in the integration of activator-TFIID contacts with promoter conformation and downstream preinitiation complex formation and/or function.

TFIIA and the transactivator Rap1 cooperate to commit TFIID for transcription initiation.

Transcription of eukaryotic messenger RNA (mRNA) encoding genes by RNA polymerase II (Pol II) is triggered by the binding of transactivating proteins to enhancer DNA, which stimulates the recruitment of general transcription factors (TFIIA, B, D, E, F, H) and Pol II on the cis-linked promoter, leading to pre-initiation complex formation and transcription. In TFIID-dependent activation pathways, this general transcription factor containing TATA-box-binding protein is first recruited on the promoter through interaction with activators and cooperates with TFIIA to form a committed pre-initiation complex. However, neither the mechanisms by which activation signals are communicated between these factors nor the structural organization of the activated pre-initiation complex are known.

Direct transactivator-transcription factor IID (TFIID) contacts drive yeast ribosomal protein gene transcription.

Transcription factor IID (TFIID) plays a key role in regulating eukaryotic gene expression by directly binding promoters and enhancer-bound transactivator proteins. However, the precise mechanisms and outcomes of transactivator-TFIID interaction remain unclear. Transcription of yeast ribosomal protein genes requires TFIID and the DNA-binding transactivator Rap1.

Ubiquitous antisense transcription in eukaryotes: novel regulatory mechanism or byproduct of opportunistic RNA polymerase?

One of the more notable observations made in the last few years in gene regulation is that eukaryotic genomes appear to be pervasively transcribed. Recent transcriptome mapping studies have shown that much of the genome is transcribed, and in some instances transcripts from both strands of specific genomic loci are detectable. While some of these transcripts map to known RNA polymerase II transcription units [that is, protein encoding open reading frames (ORFs)], many are derived from regions of DNA thought to be non-genic.

Yeast TFIID serves as a coactivator for Rap1p by direct protein-protein interaction.

In vivo studies have previously shown that Saccharomyces cerevisiae ribosomal protein (RP) gene expression is controlled by the transcription factor repressor activator protein 1 (Rap1p) in a TFIID-dependent fashion. Here we have tested the hypothesis that yeast TFIID serves as a coactivator for RP gene transcription by directly interacting with Rap1p. We have found that purified recombinant Rap1p specifically interacts with purified TFIID in pull-down assays, and we have mapped the domains of Rap1p and subunits of TFIID responsible.