31 research outputs found

    IL6Myc mouse is an immunocompetent model for the development of aggressive multiple myeloma

    Get PDF
    Multiple Myeloma (MM) is a plasma cell neoplasm originating in the bone marrow and is the second most common blood cancer in the United States. One challenge in understanding the pathogenesis of MM and improving treatment is a lack of immunocompetent mouse models. We previously developed the IL6Myc mouse that generates plasmacytomas at 100% penetrance that phenotypically resemble aggressive MM. Using comprehensive genomic analysis, we found that the IL6Myc tumors resemble aggressive MM by RNA and protein expression. We also found that IL6Myc tumors accumulated fusions and missense mutations in genes that overlap significantly with human myeloma, indicating that the mouse is good model for studying disease etiology. Lastly, we derived cell lines from IL6Myc tumors that express cell surface markers typical of MM and readily engraft into mice, home to the bone marrow, and induce osteolytic disease. The cell lines may be useful in developing immunotherapies directed against BAFF-R and TACI, though not BCMA, and may also be a good model for studying dexamethasone resistance. These data indicate that the IL6Myc model is useful for studying development of aggressive MM and for developing new treatments against such forms of the disease

    Transcriptional Regulation of Human Dual Specificity Protein Phosphatase 1 (DUSP1) Gene by Glucocorticoids

    Get PDF
    Background: Glucocorticoids are potent anti-inflammatory agents commonly used to treat inflammatory diseases. They convey signals through the intracellular glucocorticoid receptor (GR), which upon binding to ligands, associates with genomic glucocorticoid response elements (GREs) to regulate transcription of associated genes. One mechanism by which glucocorticoids inhibit inflammation is through induction of the dual specificity phosphatase-1 (DUSP1, a.k.a. mitogen-activated protein kinase phosphatase-1, MKP-1) gene. Methodology/Principal Findings: We found that glucocorticoids rapidly increased transcription of DUSP1 within 10 minutes in A549 human lung adenocarcinoma cells. Using chromatin immunoprecipitation (ChIP) scanning, we located a GR binding region between 21421 and 21118 upstream of the DUSP1 transcription start site. This region is active in a reporter system, and mutagenesis analyses identified a functional GRE located between 21337 and 21323. We found that glucocorticoids increased DNase I hypersensitivity, reduced nucleosome density, and increased histone H3 and H4 acetylation within genomic regions surrounding the GRE. ChIP experiments showed that p300 was recruited to the DUSP1 GRE, and RNA interference experiments demonstrated that reduction of p300 decreased glucocorticoid-stimulated DUSP1 gene expression and histone H3 hyperacetylation. Furthermore, overexpression of p300 potentiated glucocorticoid-stimulated activity of a reporter gene containing the DUSP1 GRE, and this coactivation effect was compromised when the histone acetyltransferase domain was mutated. ChIP-reChIP experiments using GR followed by p300 antibodies showed significant enrichment of the DUSP1 GRE upon glucocorticoid treatment, suggesting that GR and p300 are in the same protein complex recruited to the DUSP1 GRE. Conclusions/Significance: Our studies identified a functional GRE for the DUSP1 gene. Moreover, the transcriptional activation of DUSP1 by glucocorticoids requires p300 and a rapid modification of the chromatin structure surrounding the GRE. Overall, understanding the mechanism of glucocorticoid-induced DUSP1 gene transcription could provide insights into therapeutic approaches against inflammatory diseases. © 2010 Shipp et al

    The effects of sequence and mismatches on Cas9 activity

    No full text
    Non UBCUnreviewedAuthor affiliation: University of IowaFacult

    PhD

    No full text
    dissertationAutoinhibitory domains are increasingly being recognized as important means for proteins to regulate their activity in cis based on cellular cues. The transcription factor Ets-1 is regulated by an autoinhibitory module that represses the DNA binding of the ETS domain by hindering the structural rearrangement that accompanies DNA binding. However, the autoinhibitory module does not simply inhibiting binding; it serves as a versatile integrator of cell signals, including Ca2+-induced phosphorylation. This thesis explores the mechanism of autoinhibition of DNA binding in Ets-1, particularly in response to phosphorylation. Initial structural studies define the interface between the autoinhibitory module and the ETS domain. A purified multiply phosphorylated Ets-1 fragment, ?N2445P, is used to demonstrate that phosphorylation induced stabilization of the ETS domain and inhibitory module are correlated with a reduction in DNA-binding affinity. NMR spectrometry experiments reveal a dynamic hydrophobic network that connects the inhibitory module to the DNA-binding interface to form a concerted, regulatable unit. Together, these data support an allosteric model of Ets-1 DNA binding in which a dynamic hydrophobic network translates the level of phosphorylation into DNA-binding affinity by modulating the equilibrium between active and inactive conformations. Mutational analysis of the phosphorylated serine rich region indicates that multiple phosphates contribute additively to the inhibition, allowing variable control of DNA binding depending on phosphorylation state. Surprisingly, the serine rich region, which serves as an allosteric effector, is unstructured and highly mobile. Thus, rather than forming a simple on/off switch, this allosteric mechanism allows adjustable control of activity by combining flexible and folded modules. These results suggest that conformation coupling to transient interactions may provide a general mechanism of action of flexible regulatory segments

    Structural Analysis of the Autoinhibition of Ets-1 and Its Role in Protein Partnerships

    Full text link
    corecore