Browsing by Subject "Fluorescent Antibody Technique"
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Item Open Access A novel, non-apoptotic role for Scythe/BAT3: a functional switch between the pro- and anti-proliferative roles of p21 during the cell cycle.(2012) Yong, Sheila T.Scythe/BAT3 is a member of the BAG protein family whose role in apoptosis, a form of programmed cell death, has been extensively studied. However, since the developmental defects observed in Bat3‐null mouse embryos cannot be explained solely by defects in apoptosis, I investigated whether BAT3 is also involved in regulating cell‐cycle progression. Using a stable‐inducible Bat3‐knockdown cellular system, I demonstrated that reduced BAT3 protein level causes a delay in both the G1/S transition and G2/M progression. Concurrent with these changes in cell‐cycle progression, I observed a reduction in the turnover and phosphorylation of the CDK inhibitor p21. p21 is best known as an inhibitor of DNA replication; however, phosphorylated p21 has also been shown to promote G2/M progression. Additionally, I observed that the p21 turnover rate was also reduced in Bat3‐knockdown cells released from G2/M synchronization. My findings indicate that in Bat3‐knockdown cells, p21 continues to be synthesized during cell‐cycle phases that do not normally require p21, resulting in p21 protein accumulation and a subsequent cell‐cycle delay. Finally, I showed that BAT3 co‐localizes with p21 during the cell cycle and is required for the translocation of p21 from the cytoplasm to the nucleus during the G1/S transition and G2/M progression. My study reveals a novel, non‐apoptoticrole for BAT3 in cell‐cycle regulation. By maintaining low p21 protein level during G1/S transition, BAT3 counteracts the inhibitory effect of p21 on DNA replication and thus enables the cells to progress from G1 into S phase. Conversely, during G2/M progression, BAT3 facilitates p21 phosphorylation, an event that promotes G2/M progression. BAT3 modulates these pro‐ and anti‐proliferative roles of p21 at least in part by regulating the translocation of p21 between the cytoplasm and nucleus of the cells to ensure proper functioning and regulation of p21 in the appropriate intracellular compartments during different cell‐cycle phases.Item Open Access A recessive variant of XRCC4 predisposes to non- BRCA1/2 breast cancer in chinese women and impairs the DNA damage response via dysregulated nuclear localization.(Oncotarget, 2014-12) He, Min; Hu, Xin; Chen, Li; Cao, A-Yong; Yu, Ke-Da; Shi, Ting-Yan; Kuang, Xia-Ying; Shi, Wen-Biao; Ling, Hong; Li, Shan; Qiao, Feng; Yao, Ling; Wei, Qingyi; Di, Gen-Hong; Shao, Zhi-MingXRCC4 plays a crucial role in the non-homologous end joining pathway that maintains genome stability. In this two-stage case-control study with 1,764 non-BRCA1/2 breast cancer patients and 1,623 cancer-free controls, we investigated the contribution of genetic variants of XRCC4 to breast cancer susceptibility in Chinese women. We identified a recessive missense variant, rs3734091 (c.739G>T, p.Ala247Ser), of XRCC4 that was significantly associated with an increased risk of breast cancer (odds ratio [OR] = 3.92, P = 0.007), particularly with the risk of developing triple-negative breast cancer (OR = 18.65, P < 0.0001). This p.Ala247Ser variant disturbed the nuclear localization of XRCC4 in cells homozygous for the rs3734091-T allele but not in heterozygous cells at both the cellular and tissue levels. In heterozygous cells, wild-type XRCC4 facilitated the nuclear localization of the XRCC4A247S mutant, thus compensating for the impaired localization of XRCC4A247S. This provided a biological mechanism by which rs3734091 conferred an increased susceptibility to non-BRCA1/2 breast cancer exclusively under a recessive model. Further functional analyses revealed that p.Ala247Ser impaired the DNA damage repair capacity and ultimately perturbed genomic stability. Taken together, our findings document the role of XRCC4 in non-BRCA1/2 breast cancer predisposition and reveal its underlying biological mechanism of action.Item Open Access Arc/Arg3.1 translation is controlled by convergent N-methyl-D-aspartate and Gs-coupled receptor signaling pathways.(The Journal of biological chemistry, 2008-01) Bloomer, Wendy AC; VanDongen, Hendrika MA; VanDongen, Antonius MJArc/Arg3.1 is an immediate early gene whose expression is necessary for the late-phase of long-term potentiation (LTP) and memory consolidation. Whereas pathways regulating Arc transcription have been extensively investigated, less is known about the role of post-transcriptional mechanisms in Arc expression. Fluorescence microscopy experiments in cultured hippocampal neurons revealed that Arc protein level was dramatically increased by activation of the cAMP-dependent protein kinase (PKA) pathway, which is implicated in long-term memory. A PKA-dependent increase in Arc protein level was observed after pharmacological or synaptic activation of N-methyl-D-aspartate (NMDA) receptors, which play a critical role in both LTP induction and learning. Arc protein was also up-regulated by activation of PKA through G(s)-coupled dopamine and beta-adrenergic receptors, which regulate the late-phase of LTP and memory. When agonists for the NMDA and G(s)-coupled receptors were co-applied, they had an additive effect on Arc protein expression. Interestingly, G(s)-coupled receptor stimulation was ineffective in the presence of an NMDA receptor antagonist, suggesting calcium influx through the NMDA receptor plays a gating role in this pathway. Stimulation of the cAMP/PKA pathway did not affect Arc mRNA level or protein stability, identifying translational efficacy as the main determinant of Arc protein expression level. It is concluded that efficient Arc translation requires NMDA receptor activity, whereas a further enhancement can be achieved with activation of G(s)-coupled receptors. These experiments have, therefore, revealed remarkable similarities in the signaling pathways that control Arc expression and those that regulate LTP, learning, and memory.Item Open Access Dual infection with Ehrlichia chaffeensis and a spotted fever group rickettsia: a case report.(Emerging infectious diseases, 1998-04) Sexton, DJ; Corey, GR; Carpenter, C; Kong, LQ; Gandhi, T; Breitschwerdt, E; Hegarty, B; Chen, SM; Feng, HM; Yu, XJ; Olano, J; Walker, DH; Dumler, SJWell-documented cases of simultaneous human infection with more than one tick-borne pathogen are rare. To our knowledge only two dual infections have been reported: simultaneous human infection with the agent of human granulocytic ehrlichiosis and Borrelia burgdorferi and simultaneous human infection with B. burgdorferi and Babesia microti (1-2). Rocky Mountain spotted fever has long been known to be endemic in North Carolina; cases of human ehrlichial infection were recognized there soon after Ehrlichia chaffeensis was recognized as an important cause of tick-borne disease in the southeastern United States. Because both Rocky Mountain spotted fever and ehrlichiosis are prevalent in North Carolina, occasional cases of simultaneous human infection by rickettsial and ehrlichial agents would not be surprising; however, no such cases seem to have been reported.Item Open Access Enhanced In Vivo Delivery of Stem Cells using Microporous Annealed Particle Scaffolds.(Small (Weinheim an der Bergstrasse, Germany), 2019-09) Koh, Jaekyung; Griffin, Donald R; Archang, Maani M; Feng, An-Chieh; Horn, Thomas; Margolis, Michael; Zalazar, David; Segura, Tatiana; Scumpia, Philip O; Di Carlo, DinoDelivery to the proper tissue compartment is a major obstacle hampering the potential of cellular therapeutics for medical conditions. Delivery of cells within biomaterials may improve localization, but traditional and newer void-forming hydrogels must be made in advance with cells being added into the scaffold during the manufacturing process. Injectable, in situ cross-linking microporous scaffolds are recently developed that demonstrate a remarkable ability to provide a matrix for cellular proliferation and growth in vitro in three dimensions. The ability of these scaffolds to deliver cells in vivo is currently unknown. Herein, it is shown that mesenchymal stem cells (MSCs) can be co-injected locally with microparticle scaffolds assembled in situ immediately following injection. MSC delivery within a microporous scaffold enhances MSC retention subcutaneously when compared to cell delivery alone or delivery within traditional in situ cross-linked nanoporous hydrogels. After two weeks, endothelial cells forming blood vessels are recruited to the scaffold and cells retaining the MSC marker CD29 remain viable within the scaffold. These findings highlight the utility of this approach in achieving localized delivery of stem cells through an injectable porous matrix while limiting obstacles of introducing cells within the scaffold manufacturing process.Item Open Access Human Non-neutralizing HIV-1 Envelope Monoclonal Antibodies Limit the Number of Founder Viruses during SHIV Mucosal Infection in Rhesus Macaques.(PLoS Pathog, 2015-08) Santra, Sampa; Tomaras, Georgia D; Warrier, Ranjit; Nicely, Nathan I; Liao, Hua-Xin; Pollara, Justin; Liu, Pinghuang; Alam, S Munir; Zhang, Ruijun; Cocklin, Sarah L; Shen, Xiaoying; Duffy, Ryan; Xia, Shi-Mao; Schutte, Robert J; Pemble Iv, Charles W; Dennison, S Moses; Li, Hui; Chao, Andrew; Vidnovic, Kora; Evans, Abbey; Klein, Katja; Kumar, Amit; Robinson, James; Landucci, Gary; Forthal, Donald N; Montefiori, David C; Kaewkungwal, Jaranit; Nitayaphan, Sorachai; Pitisuttithum, Punnee; Rerks-Ngarm, Supachai; Robb, Merlin L; Michael, Nelson L; Kim, Jerome H; Soderberg, Kelly A; Giorgi, Elena E; Blair, Lily; Korber, Bette T; Moog, Christiane; Shattock, Robin J; Letvin, Norman L; Schmitz, Joern E; Moody, MA; Gao, Feng; Ferrari, Guido; Shaw, George M; Haynes, Barton FHIV-1 mucosal transmission begins with virus or virus-infected cells moving through mucus across mucosal epithelium to infect CD4+ T cells. Although broadly neutralizing antibodies (bnAbs) are the type of HIV-1 antibodies that are most likely protective, they are not induced with current vaccine candidates. In contrast, antibodies that do not neutralize primary HIV-1 strains in the TZM-bl infection assay are readily induced by current vaccine candidates and have also been implicated as secondary correlates of decreased HIV-1 risk in the RV144 vaccine efficacy trial. Here, we have studied the capacity of anti-Env monoclonal antibodies (mAbs) against either the immunodominant region of gp41 (7B2 IgG1), the first constant region of gp120 (A32 IgG1), or the third variable loop (V3) of gp120 (CH22 IgG1) to modulate in vivo rectal mucosal transmission of a high-dose simian-human immunodeficiency virus (SHIV-BaL) in rhesus macaques. 7B2 IgG1 or A32 IgG1, each containing mutations to enhance Fc function, was administered passively to rhesus macaques but afforded no protection against productive clinical infection while the positive control antibody CH22 IgG1 prevented infection in 4 of 6 animals. Enumeration of transmitted/founder (T/F) viruses revealed that passive infusion of each of the three antibodies significantly reduced the number of T/F genomes. Thus, some antibodies that bind HIV-1 Env but fail to neutralize virus in traditional neutralization assays may limit the number of T/F viruses involved in transmission without leading to enhancement of viral infection. For one of these mAbs, gp41 mAb 7B2, we provide the first co-crystal structure in complex with a common cyclical loop motif demonstrated to be critical for infection by other retroviruses.Item Open Access Intrastromal Gene Therapy Prevents and Reverses Advanced Corneal Clouding in a Canine Model of Mucopolysaccharidosis I.(Molecular therapy : the journal of the American Society of Gene Therapy, 2020-06) Miyadera, Keiko; Conatser, Laura; Llanga, Telmo A; Carlin, Kendall; O'Donnell, Patricia; Bagel, Jessica; Song, Liujiang; Kurtzberg, Joanne; Samulski, R Jude; Gilger, Brian; Hirsch, Matthew LMucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disease characterized by severe phenotypes, including corneal clouding. MPS I is caused by mutations in alpha-l-iduronidase (IDUA), a ubiquitous enzyme that catalyzes the hydrolysis of glycosaminoglycans. Currently, no treatment exists to address MPS I corneal clouding other than corneal transplantation, which is complicated by a high risk for rejection. Investigation of an adeno-associated virus (AAV) IDUA gene addition strategy targeting the corneal stroma addresses this deficiency. In MPS I canines with early or advanced corneal disease, a single intrastromal AAV8G9-IDUA injection was well tolerated at all administered doses. The eyes with advanced disease demonstrated resolution of corneal clouding as early as 1 week post-injection, followed by sustained corneal transparency until the experimental endpoint of 25 weeks. AAV8G9-IDUA injection in the MPS I canine eye with early corneal disease prevented the development of advanced corneal changes while restoring clarity. Biodistribution studies demonstrated vector genomes in ocular compartments other than the cornea and in some systemic organs; however, a capsid antibody response was detected in only the highest dosed subject. Collectively, the results suggest that intrastromal AAV8G9-IDUA therapy prevents and reverses visual impairment associated with MPS I corneal clouding.Item Open Access Molecular imaging of a fluorescent antibody against epidermal growth factor receptor detects high-grade glioma.(Scientific reports, 2021-03) Zhou, Quan; Vega Leonel, Johana CM; Santoso, Michelle Rai; Wilson, Christy; van den Berg, Nynke S; Chan, Carmel T; Aryal, Muna; Vogel, Hannes; Cayrol, Romain; Mandella, Michael J; Schonig, Frank; Lu, Guolan; Gambhir, Sanjiv S; Moseley, Michael E; Rosenthal, Eben L; Grant, Gerald AThe prognosis for high-grade glioma (HGG) remains dismal and the extent of resection correlates with overall survival and progression free disease. Epidermal growth factor receptor (EGFR) is a biomarker heterogeneously expressed in HGG. We assessed the feasibility of detecting HGG using near-infrared fluorescent antibody targeting EGFR. Mice bearing orthotopic HGG xenografts with modest EGFR expression were imaged in vivo after systemic panitumumab-IRDye800 injection to assess its tumor-specific uptake macroscopically over 14 days, and microscopically ex vivo. EGFR immunohistochemical staining of 59 tumor specimens from 35 HGG patients was scored by pathologists and expression levels were compared to that of mouse xenografts. Intratumoral distribution of panitumumab-IRDye800 correlated with near-infrared fluorescence and EGFR expression. Fluorescence distinguished tumor cells with 90% specificity and 82.5% sensitivity. Target-to-background ratios peaked at 14 h post panitumumab-IRDye800 infusion, reaching 19.5 in vivo and 7.6 ex vivo, respectively. Equivalent or higher EGFR protein expression compared to the mouse xenografts was present in 77.1% HGG patients. Age, combined with IDH-wildtype cerebral tumor, was predictive of greater EGFR protein expression in human tumors. Tumor specific uptake of panitumumab-IRDye800 provided remarkable contrast and a flexible imaging window for fluorescence-guided identification of HGGs despite modest EGFR expression.Item Open Access Neuron-specific SUMO knockdown suppresses global gene expression response and worsens functional outcome after transient forebrain ischemia in mice.(Neuroscience, 2017-02) Zhang, Lin; Liu, Xiaozhi; Sheng, Huaxin; Liu, Shuai; Li, Ying; Zhao, Julia Q; Warner, David S; Paschen, Wulf; Yang, WeiSmall ubiquitin-like modifier (SUMO) conjugation (SUMOylation) plays key roles in neurologic function in health and disease. Neuronal SUMOylation is essential for emotionality and cognition, and this pathway is dramatically activated in post-ischemic neurons, a neuroprotective response to ischemia. It is also known from cell culture studies that SUMOylation modulates gene expression. However, it remains unknown how SUMOylation regulates neuronal gene expression in vivo, in the physiologic state and after ischemia, and modulates post-ischemic recovery of neurologic function. To address these important questions, we used a SUMO1-3 knockdown (SUMO-KD) mouse in which a Thy-1 promoter drives expression of 3 distinct microRNAs against SUMO1-3 to silence SUMO expression specifically in neurons. Wild-type and SUMO-KD mice were subjected to transient forebrain ischemia. Microarray analysis was performed in hippocampal CA1 samples, and neurologic function was evaluated. SUMOylation had opposite effects on neuronal gene expression before and after ischemia. In the physiological state, most genes regulated by SUMOylation were up-regulated in SUMO-KD compared to wild-type mice. Brain ischemia/reperfusion significantly modulated the expression levels of more than 400 genes in wild-type mice, with a majority of those genes upregulated. The extent of this post-ischemic transcriptome change was suppressed in SUMO-KD mice. Moreover, SUMO-KD mice exhibited significantly worse functional outcome. This suggests that suppression of global gene expression response in post-ischemic brain due to SUMO knockdown has a negative effect on post-ischemic neurologic function. Together, our data provide a basis for future studies to mechanistically link SUMOylation to neurologic function in health and disease.Item Open Access Neuron-specific Sumo1-3 knockdown in mice impairs episodic and fear memories.(Journal of psychiatry & neuroscience : JPN, 2014-07) Wang, Liangli; Rodriguiz, Ramona M; Wetsel, William C; Sheng, Huaxin; Zhao, Shengli; Liu, Xiaozhi; Paschen, Wulf; Yang, WeiBACKGROUND:Growing evidence suggests that small ubiquitin-like modifier (SUMO) conjugation plays a key role in brain plasticity by modulating activity-dependent synaptic transmission. However, these observations are based largely on cell culture experiments. We hypothesized that episodic and fear memories would be affected by silencing SUMO1-3 expression. METHODS:To investigate the role of SUMO conjugation in neuronal functioning in vivo, we generated a novel Sumo transgenic mouse model in which a Thy1 promoter drives expression of 3 distinct microRNAs to silence Sumo1-3 expression, specifically in neurons. Wild-type and Sumo1-3 knockdown mice were subjected to a battery of behavioural tests to elucidate whether Sumoylation is involved in episodic and emotional memory. RESULTS:Expression of Sumo1-3 microRNAs and the corresponding silencing of Sumo expression were particularly pronounced in hippocampal, amygdala and layer V cerebral cortex neurons. The Sumo knockdown mice displayed anxiety-like responses and were impaired in episodic memory processes, contextual and cued fear conditioning and fear-potentiated startle. LIMITATIONS:Since expression of Sumo1-3 was silenced in this mouse model, we need to verify in future studies which of the SUMO paralogues play the pivotal role in episodic and emotional memory. CONCLUSION:Our results indicate that a functional SUMO conjugation pathway is essential for emotionality and cognition. This novel Sumo knockdown mouse model and the technology used in generating this mutant may help to reveal novel mechanisms that underlie a variety of neuropsychiatric conditions associated with anxiety and impairment of episodic and emotional memory.Item Open Access Role of endocytosis in the activation of the extracellular signal-regulated kinase cascade by sequestering and nonsequestering G protein-coupled receptors.(Proc Natl Acad Sci U S A, 2000-02-15) Pierce, KL; Maudsley, S; Daaka, Y; Luttrell, LM; Lefkowitz, RJActing through a number of distinct pathways, many G protein-coupled receptors (GPCRs) activate the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) cascade. Recently, it has been shown that in some cases, clathrin-mediated endocytosis is required for GPCR activation of the ERK/MAPK cascade, whereas in others it is not. Accordingly, we compared ERK activation mediated by a GPCR that does not undergo agonist-stimulated endocytosis, the alpha(2A) adrenergic receptor (alpha(2A) AR), with ERK activation mediated by the beta(2) adrenergic receptor (beta(2) AR), which is endocytosed. Surprisingly, we found that in COS-7 cells, ERK activation by the alpha(2A) AR, like that mediated by both the beta(2) AR and the epidermal growth factor receptor (EGFR), is sensitive to mechanistically distinct inhibitors of clathrin-mediated endocytosis, including monodansylcadaverine, a mutant dynamin I, and a mutant beta-arrestin 1. Moreover, we determined that, as has been shown for many other GPCRs, both alpha(2A) and beta(2) AR-mediated ERK activation involves transactivation of the EGFR. Using confocal immunofluorescence microscopy, we found that stimulation of the beta(2) AR, the alpha(2A) AR, or the EGFR each results in internalization of a green fluorescent protein-tagged EGFR. Although beta(2) AR stimulation leads to redistribution of both the beta(2) AR and EGFR, activation of the alpha(2A) AR leads to redistribution of the EGFR but the alpha(2A) AR remains on the plasma membrane. These findings separate GPCR endocytosis from the requirement for clathrin-mediated endocytosis in EGFR transactivation-mediated ERK activation and suggest that it is the receptor tyrosine kinase or another downstream effector that must engage the endocytic machinery.Item Open Access SIV-induced terminally differentiated adaptive NK cells in lymph nodes associated with enhanced MHC-E restricted activity.(Nature communications, 2021-02-24) Huot, Nicolas; Rascle, Philippe; Petitdemange, Caroline; Contreras, Vanessa; Stürzel, Christina M; Baquero, Eduard; Harper, Justin L; Passaes, Caroline; Legendre, Rachel; Varet, Hugo; Madec, Yoann; Sauermann, Ulrike; Stahl-Hennig, Christiane; Nattermann, Jacob; Saez-Cirion, Asier; Le Grand, Roger; Keith Reeves, R; Paiardini, Mirko; Kirchhoff, Frank; Jacquelin, Beatrice; Müller-Trutwin, MichaelaNatural killer (NK) cells play a critical understudied role during HIV infection in tissues. In a natural host of SIV, the African green monkey (AGM), NK cells mediate a strong control of SIVagm infection in secondary lymphoid tissues. We demonstrate that SIVagm infection induces the expansion of terminally differentiated NKG2alow NK cells in secondary lymphoid organs displaying an adaptive transcriptional profile and increased MHC-E-restricted cytotoxicity in response to SIV Env peptides while expressing little IFN-γ. Such NK cell differentiation was lacking in SIVmac-infected macaques. Adaptive NK cells displayed no increased NKG2C expression. This study reveals a previously unknown profile of NK cell adaptation to a viral infection, thus accelerating strategies toward NK-cell directed therapies and viral control in tissues.Item Open Access Targeting A20 decreases glioma stem cell survival and tumor growth.(PLoS Biol, 2010-02-23) Hjelmeland, AB; Wu, Q; Wickman, S; Eyler, C; Heddleston, J; Shi, Q; Lathia, JD; Macswords, J; Lee, J; McLendon, RE; Rich, JNGlioblastomas are deadly cancers that display a functional cellular hierarchy maintained by self-renewing glioblastoma stem cells (GSCs). GSCs are regulated by molecular pathways distinct from the bulk tumor that may be useful therapeutic targets. We determined that A20 (TNFAIP3), a regulator of cell survival and the NF-kappaB pathway, is overexpressed in GSCs relative to non-stem glioblastoma cells at both the mRNA and protein levels. To determine the functional significance of A20 in GSCs, we targeted A20 expression with lentiviral-mediated delivery of short hairpin RNA (shRNA). Inhibiting A20 expression decreased GSC growth and survival through mechanisms associated with decreased cell-cycle progression and decreased phosphorylation of p65/RelA. Elevated levels of A20 in GSCs contributed to apoptotic resistance: GSCs were less susceptible to TNFalpha-induced cell death than matched non-stem glioma cells, but A20 knockdown sensitized GSCs to TNFalpha-mediated apoptosis. The decreased survival of GSCs upon A20 knockdown contributed to the reduced ability of these cells to self-renew in primary and secondary neurosphere formation assays. The tumorigenic potential of GSCs was decreased with A20 targeting, resulting in increased survival of mice bearing human glioma xenografts. In silico analysis of a glioma patient genomic database indicates that A20 overexpression and amplification is inversely correlated with survival. Together these data indicate that A20 contributes to glioma maintenance through effects on the glioma stem cell subpopulation. Although inactivating mutations in A20 in lymphoma suggest A20 can act as a tumor suppressor, similar point mutations have not been identified through glioma genomic sequencing: in fact, our data suggest A20 may function as a tumor enhancer in glioma through promotion of GSC survival. A20 anticancer therapies should therefore be viewed with caution as effects will likely differ depending on the tumor type.Item Restricted Tissue type-specific expression of the dsRNA-binding protein 76 and genome-wide elucidation of its target mRNAs.(PLoS One, 2010-07-23) Neplioueva, Valentina; Dobrikova, Elena Y; Mukherjee, Neelanjan; Keene, Jack D; Gromeier, MatthiasBACKGROUND: RNA-binding proteins accompany all steps in the life of mRNAs and provide dynamic gene regulatory functions for rapid adjustment to changing extra- or intracellular conditions. The association of RNA-binding proteins with their targets is regulated through changing subcellular distribution, post-translational modification or association with other proteins. METHODOLOGY: We demonstrate that the dsRNA binding protein 76 (DRBP76), synonymous with nuclear factor 90, displays inherently distinct tissue type-specific subcellular distribution in the normal human central nervous system and in malignant brain tumors of glial origin. Altered subcellular localization and isoform distribution in malignant glioma indicate that tumor-specific changes in DRBP76-related gene products and their regulatory functions may contribute to the formation and/or maintenance of these tumors. To identify endogenous mRNA targets of DRBP76, we performed RNA-immunoprecipitation and genome-wide microarray analyses in HEK293 cells, and identified specific classes of transcripts encoding critical functions in cellular metabolism. SIGNIFICANCE: Our data suggest that physiologic DRBP76 expression, isoform distribution and subcellular localization are profoundly altered upon malignant transformation. Thus, the functional role of DRBP76 in co- or post-transcriptional gene regulation may contribute to the neoplastic phenotype.