Targeted deletion of Ruvbl1 results in severe defects of epidermal development and perinatal mortality.
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ABSTRACT:
PROVIDER: S-EPMC7881068 | BioStudies |
REPOSITORIES: biostudies
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Project description:RUVBL1 and RUVBL2 (collectively RUVBL1/2) are essential AAA+ ATPases that function as co-chaperones and have been implicated in cancer. Here we investigated the molecular and phenotypic role of RUVBL1/2 ATPase activity in non-small cell lung cancer (NSCLC). We find that RUVBL1/2 are overexpressed in NSCLC patient tumors, with high expression associated with poor survival. Utilizing a specific inhibitor of RUVBL1/2 ATPase activity, we show that RUVBL1/2 ATPase activity is necessary for the maturation or dissociation of the PAQosome, a large RUVBL1/2-dependent multiprotein complex. We also show that RUVBL1/2 have roles in DNA replication, as inhibition of its ATPase activity can cause S-phase arrest, which culminates in cancer cell death via replication catastrophe. While in vivo pharmacological inhibition of RUVBL1/2 results in modest antitumor activity, it synergizes with radiation in NSCLC, but not normal cells, an attractive property for future preclinical development.
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Project description:RUVBL1 (RuvB-like1) and RUVBL2 (RuvB-like 2) are integral components of multisubunit protein complexes involved in processes ranging from cellular metabolism, transcription and chromatin remodeling to DNA repair. Here, we show that although RUVBL1 and RUVBL2 are known to form heterodimeric complexes in which they stabilize each other, the subunits separate during cytokinesis. In anaphase-to-telophase transition, RUVBL1 localizes to structures of the mitotic spindle apparatus, where it partially co-localizes with polo-like kinase 1 (PLK1). The ability of PLK1 to phosphorylate RUVBL1-but not RUVBL2-in vitro and their physical association in vivo suggest that this kinase differentially regulates the function of the RuvB-like proteins during mitosis. We further show that siRNA-mediated knock-down of RuvB-like proteins causes severe defects in chromosome alignment and segregation. In addition, we show that the ATPase activity of RUVBL1 is indispensable for cell proliferation. Our data thus demonstrate that RUVBL1 is essential for efficient mitosis and proliferation.
| S-EPMC4511761 | BioStudies
Project description:RUVBL1 and RUVBL2 (collectively RUVBL1/2) are essential AAA+ ATPases that function as co-chaperones and have been implicated in cancer. Here we investigated the molecular and phenotypic role of RUVBL1/2 ATPase activity in non-small cell lung cancer (NSCLC). We find that RUVBL1/2 are overexpressed in NSCLC patient tumors, with high expression prognostic of poor survival. Utilizing a highly specific inhibitor of RUVBL1/2 ATPase activity, we show that RUVBL1/2 ATPase activity is necessary for the maturation of the PAQosome, a large RUVBL1/2-dependent multiprotein complex. We also show that RUVBL1/2 have roles in DNA replication, as inhibition of their ATPase activity impedes RPA loading at replication forks, decreases fork stability, and ultimately results in replication catastrophe and cancer cell death. While in vivo pharmacological inhibition of RUVBL1/2 results in modest antitumor activity, it synergizes with radiation in NSCLC, but not normal cells, an attractive property for future preclinical development. Overall design: Analyze the transcriptomic response of RUVBL1 knockdown (siBL1) or RUVBL1 inhibition (compB) in two different non-small cell lung cancer cell lines (H2009 and H596)
2019-12-18 | GSE107637 | GEO
Project description:During development, a polarized sheet of epidermal cells undergoes stratification and differentiation to produce the skin barrier. Through mechanisms poorly understood, the process involves adhesion and Notch signaling. To elucidate how epidermal embryogenesis is governed, we conditionally targeted transcription factor serum response factor (SRF), which has been shown to be essential for proper epidermal differentiation in vitro and in vivo. Seeking mechanism, we identified actomyosin-related genes as well-known SRF targets downregulated shortly after ablation. We show that this results in a diminished cortical actomyosin network which fails to regulate the transition of cells from the basal proliferative layer to the suprabasal differentiating layer resulting in an inability of cells to properly execute stratification and differentiation. FACS purification of basal epidermal cells from E16.5 SRF fl/fl ROSA26 YFP fl/fl K14-Cre (cKO) or SRF fl/+ ROSA26 YFP fl/fl K14-Cre (WT) was performed on a FACS Vantage SE system equipped with FACS DiVa software (BD Biosciences). Cells were gated for single events and viability and then sorted according to α6 integrin-PE expression and YFP.
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Project description:Lung cancer is the common malignant tumor with the highest death rate in the world. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as a potential anticancer agent induces selective apoptotic death of human cancer cells. Unfortunately, approximately half of lung cancer cell lines are intrinsically resistant to TRAIL-induced cell death. In this study, we identified RuvBL1 as a repressor of c-Jun/AP-1 activity, contributing to TRAIL resistance in lung cancer cells. Knocking down RuvBL1 effectively sensitized resistant cells to TRAIL, and overexpression of RuvBL1 inhibited TRAIL-induced apoptosis. Moreover, there was a negative correlation expression between RuvBL1 and c-Jun in lung adenocarcinoma by Oncomine analyses. High expression of RuvBL1 inversely with low c-Jun in lung cancer was associated with a poor overall prognosis. Taken together, our studies broaden the molecular mechanisms of TRAIL resistance and suggest the application of silencing RuvBL1 synergized with TRAIL to be a novel therapeutic strategy in lung cancer treatment.
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Project description:The human BCL6 gene, which is involved in the pathogenesis of certain human lymphomas, encodes a transcriptional repressor that is needed for germinal center B cell development and T follicular helper cell differentiation. Our goal was to identify BCL6 target genes using a cell system in which BCL6 repressive effects are inhibited followed by subtractive hybridization, and we detected the RUVBL1 (Pontin, TIP49) gene as a potential target of BCL6 repression. Here we show that the BCL6 protein significantly represses RUVBL1 transcription (6.8-fold). Knockdown of endogenous BCL6 in a human B cell lymphoma line leads to significant upregulation of RUVBL1, and there is an inverse expression pattern between the BCL6 and RUVBL1 proteins in certain human lymphomas. RUVBL1 is part of the AAA+ superfamily and participates in multiple processes, including gene transcription regulation, chromatin remodeling, and DNA repair, which, if dysregulated, may promote lymphoma development. A further understanding of the relationship between RUVBL1 and BCL6 should improve our understanding of the pathogenesis of human lymphomas.
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Project description:DNAAF1 (LRRC50) is a cytoplasmic protein required for dynein heavy chain assembly and cilia motility, and DNAAF1 mutations cause primary ciliary dyskinesia (PCD; MIM 613193). We describe four families with DNAAF1 mutations and complex congenital heart disease (CHD). In three families, all affected individuals have typical PCD phenotypes. However, an additional family demonstrates isolated CHD (heterotaxy) in two affected siblings, but no clinical evidence of PCD. We identified a homozygous DNAAF1 missense mutation, p.Leu191Phe, as causative for heterotaxy in this family. Genetic complementation in dnaaf1-null zebrafish embryos demonstrated the rescue of normal heart looping with wild-type human DNAAF1, but not the p.Leu191Phe variant, supporting the conserved pathogenicity of this DNAAF1 missense mutation. This observation points to a phenotypic continuum between CHD and PCD, providing new insights into the pathogenesis of isolated CHD. In further investigations of the function of DNAAF1 in dynein arm assembly, we identified interactions with members of a putative dynein arm assembly complex. These include the ciliary intraflagellar transport protein IFT88 and the AAA+?(ATPases Associated with various cellular Activities) family proteins RUVBL1 (Pontin) and RUVBL2 (Reptin). Co-localization studies support these findings, with the loss of RUVBL1 perturbing the co-localization of DNAAF1 with IFT88. We show that RUVBL1 orthologues have an asymmetric left-sided distribution at both the mouse embryonic node and the Kupffer's vesicle in zebrafish embryos, with the latter asymmetry dependent on DNAAF1. These results suggest that DNAAF1-RUVBL1 biochemical and genetic interactions have a novel functional role in symmetry breaking and cardiac development.
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Project description:Fanconi anaemia (FA) is a genome instability disease caused by defects in the FA DNA repair pathway that senses and repairs damage caused by DNA interstrand crosslinks. At least 8 of the 16 genes found mutated in FA encode proteins that assemble into the FA core complex, a multisubunit monoubiquitin E3 ligase. Here, we show that the RuvBL1 and RuvBL2 AAA+ ATPases co-purify with FA core complex isolated under stringent but native conditions from a vertebrate cell line. Depletion of the RuvBL1-RuvBL2 complex in human cells causes hallmark features of FA including DNA crosslinker sensitivity, chromosomal instability and defective FA pathway activation. Genetic knockout of RuvBL1 in a murine model is embryonic lethal while conditional inactivation in the haematopoietic stem cell pool confers profound aplastic anaemia. Together these findings reveal a function for RuvBL1-RuvBL2 in DNA repair through a physical and functional association with the FA core complex. Surprisingly, depletion of RuvBL1-RuvBL2 leads to co-depletion of the FA core complex in human cells. This suggests that a potential mechanism for the role of RuvBL1-RuvBL2 in maintaining genome integrity is through controlling the cellular abundance of FA core complex.
| S-EPMC4267650 | BioStudies
Project description:Macrophages play an important role in the host defense mechanism. In response to infection, macrophages activate a genetic program of pro-inflammatory response to kill any invading pathogen, and initiate an adaptive immune response. We have identified RUVBL2 - an ATP-binding protein belonging to the AAA+ (ATPase associated with diverse cellular activities) superfamily of ATPases - as a novel regulator in pro-inflammatory response of macrophages. Gene knockdown of <i>Ruvbl2</i>, or pharmacological inhibition of RUVBL1/2 activity, compromises type-2 nitric oxide synthase (<i>Nos2</i>) gene expression, nitric oxide production and anti-bacterial activity of mouse macrophages in response to lipopolysaccharides (LPS). RUVBL1/2 inhibitor similarly inhibits pro-inflammatory response in human monocytes, suggesting functional conservation of RUVBL1/2 in humans. Transcriptome analysis further revealed that major LPS-induced pro-inflammatory pathways in macrophages are regulated in a RUVBL1/2-dependent manner. Furthermore, RUVBL1/2 inhibition significantly reduced the level of histone H3K4me3 at the promoter region of <i>Nos2</i> and <i>Il6</i>, two prototypical pro-inflammatory genes, and diminished the recruitment of NF-kappaB to the corresponding enhancers. Our study reveals RUVBL1/2 as an integral component of macrophage pro-inflammatory responses through epigenetic regulations, and the therapeutic potentials of RUVBL1/2 inhibitors in the treatment of diseases caused by aberrant activation of pro-inflammatory pathways.
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Project description:Yin Yang 1 (YY1) is a transcription factor regulating proliferation and differentiation and is involved in cancer development. Oligomers of recombinant YY1 have been observed before, but their structure and DNA binding properties are not well understood. Here we find that YY1 assembles several homo-oligomeric species built from the association of a bell-shaped dimer, a process we characterized by electron microscopy. Moreover, we find that YY1 self-association also occurs in vivo using bimolecular fluorescence complementation. Unexpectedly, these oligomers recognize several DNA substrates without the consensus sequence for YY1 in vitro, and DNA binding is enhanced in the presence of RuvBL1-RuvBL2, two essential AAA+ ATPases. YY1 oligomers bind RuvBL1-RuvBL2 hetero-oligomeric complexes, but YY1 interacts preferentially with RuvBL1. Collectively, these findings suggest that YY1-RuvBL1-RuvBL2 complexes could contribute to functions beyond transcription, and we show that YY1 and the ATPase activity of RuvBL2 are required for RAD51 foci formation during homologous recombination.
| S-EPMC4132769 | BioStudies