David M Valenzuela

Regeneron, Terryville, New York, United States

Are you David M Valenzuela?

Claim your profile

Publications (98)1274.46 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: G protein-coupled receptor 17 (GPR17) was recently reported to be a Foxo1 target in agouti-related peptide (AGRP) neurons. Intracerebroventricular injection of GPR17 agonists induced food intake, whereas administration of an antagonist to the receptor reduced feeding. These data lead to the conclusion that pharmacological modulation of GPR17 has therapeutic potential to treat obesity. Here we report that mice deficient in Gpr17 (Gpr17(-/-)) have similar food intake and body weight compared with their wild-type littermates. Gpr17(-/-) mice have normal hypothalamic Agrp mRNA expression, AGRP plasma levels, and metabolic rate. GPR17 deficiency in mice did not affect glucose homeostasis or prevent fat-induced insulin resistance. These data do not support a role for GPR17 in the control of food intake, body weight, or glycemic control.
    Proceedings of the National Academy of Sciences 01/2015; 112(6):1845-1849. DOI:10.1073/pnas.1424968112 · 9.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Despite antiretroviral therapy (ART), human immunodeficiency virus (HIV)-1 persists in a stable latent reservoir, primarily in resting memory CD4(+) T cells. This reservoir presents a major barrier to the cure of HIV-1 infection. To purge the reservoir, pharmacological reactivation of latent HIV-1 has been proposed and tested both in vitro and in vivo. A key remaining question is whether virus-specific immune mechanisms, including cytotoxic T lymphocytes (CTLs), can clear infected cells in ART-treated patients after latency is reversed. Here we show that there is a striking all or none pattern for CTL escape mutations in HIV-1 Gag epitopes. Unless ART is started early, the vast majority (>98%) of latent viruses carry CTL escape mutations that render infected cells insensitive to CTLs directed at common epitopes. To solve this problem, we identified CTLs that could recognize epitopes from latent HIV-1 that were unmutated in every chronically infected patient tested. Upon stimulation, these CTLs eliminated target cells infected with autologous virus derived from the latent reservoir, both in vitro and in patient-derived humanized mice. The predominance of CTL-resistant viruses in the latent reservoir poses a major challenge to viral eradication. Our results demonstrate that chronically infected patients retain a broad-spectrum viral-specific CTL response and that appropriate boosting of this response may be required for the elimination of the latent reservoir.
    Nature 01/2015; DOI:10.1038/nature14053 · 42.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Known examples of male to female sex reversal in mice are caused by either strain incompatibilities or mutations in genes required for male sex determination. The resultant XY females are often sterile or exhibit very poor fertility. We describe here embryonic stem (ES) cell growth conditions that promote the production of healthy, anatomically normal fertile and fecund female F0 generation mice completely derived from gene-targeted XY male ES cells. The sex reversal is a transient trait that is not transmitted to the F1 progeny. Growth media with low osmolality and reduced sodium bicarbonate, maintained throughout the gene targeting process, enhance the yield of XY females. As a practical application of the induced sex reversal, we demonstrate the generation of homozygous mutant mice ready for phenotypic studies by the breeding of F0 XY females with their isogenic XY male clonal siblings, thereby eliminating one generation of breeding and the associated costs.
    Transgenic Research 08/2014; 24(1). DOI:10.1007/s11248-014-9815-y · 2.28 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Genetic humanization, which involves replacing mouse genes with their human counterparts, can create powerful animal models for the study of human genes and diseases. One important example of genetic humanization involves mice humanized for their Ig genes, allowing for human antibody responses within a mouse background (HumAb mice) and also providing a valuable platform for the generation of fully human antibodies as therapeutics. However, existing HumAb mice do not have fully functional immune systems, perhaps because of the manner in which they were genetically humanized. Heretofore, most genetic humanizations have involved disruption of the endogenous mouse gene with simultaneous introduction of a human transgene at a new and random location (so-called KO-plus-transgenic humanization). More recent efforts have attempted to replace mouse genes with their human counterparts at the same genetic location (in situ humanization), but such efforts involved laborious procedures and were limited in size and precision. We describe a general and efficient method for very large, in situ, and precise genetic humanization using large compound bacterial artificial chromosome-based targeting vectors introduced into mouse ES cells. We applied this method to genetically humanize 3-Mb segments of both the mouse heavy and κ light chain Ig loci, by far the largest genetic humanizations ever described. This paper provides a detailed description of our genetic humanization approach, and the companion paper reports that the humoral immune systems of mice bearing these genetically humanized loci function as efficiently as those of WT mice.
    Proceedings of the National Academy of Sciences 03/2014; DOI:10.1073/pnas.1323896111 · 9.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Mice genetically engineered to be humanized for their Ig genes allow for human antibody responses within a mouse background (HumAb mice), providing a valuable platform for the generation of fully human therapeutic antibodies. Unfortunately, existing HumAb mice do not have fully functional immune systems, perhaps because of the manner in which their genetic humanization was carried out. Heretofore, HumAb mice have been generated by disrupting the endogenous mouse Ig genes and simultaneously introducing human Ig transgenes at a different and random location; KO-plus-transgenic humanization. As we describe in the companion paper, we attempted to make mice that more efficiently use human variable region segments in their humoral responses by precisely replacing 6 Mb of mouse Ig heavy and kappa light variable region germ-line gene segments with their human counterparts while leaving the mouse constant regions intact, using a unique in situ humanization approach. We reasoned the introduced human variable region gene segments would function indistinguishably in their new genetic location, whereas the retained mouse constant regions would allow for optimal interactions and selection of the resulting antibodies within the mouse environment. We show that these mice, termed VelocImmune mice because they were generated using VelociGene technology, efficiently produce human:mouse hybrid antibodies (that are rapidly convertible to fully human antibodies) and have fully functional humoral immune systems indistinguishable from those of WT mice. The efficiency of the VelocImmune approach is confirmed by the rapid progression of 10 different fully human antibodies into human clinical trials.
    Proceedings of the National Academy of Sciences 03/2014; DOI:10.1073/pnas.1324022111 · 9.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Diffuse infiltrative invasion is a major cause for the dismal prognosis of glioblastoma multiforme (GBM), but the underlying mechanisms remain incompletely understood. Using human glioma stem cells (GSCs) that recapitulate the invasive propensity of primary GBM, we find that EphA2 critically regulates GBM invasion in vivo. EphA2 was expressed in all seven GSC lines examined, and overexpression of EphA2 enhanced intracranial invasion. The effects required Akt-mediated phosphorylation of EphA2 on serine 897. In vitro the Akt-EphA2 signaling axis is maintained in the absence of ephrin-A ligands and is disrupted upon ligand stimulation. To test whether ephrin-As in tumor microenvironment can regulate GSC invasion, the newly established Efna1;Efna3;Efna4 triple knockout mice (TKO) were used in an ex vivo brain slice invasion assay. We observed significantly increased GSC invasion through the brain slices of TKO mice relative to wild-type (WT) littermates. Mechanistically EphA2 knockdown suppressed stem cell properties of GSCs, causing diminished self-renewal, reduced stem marker expression and decreased tumorigenicity. In a subset of GSCs, the reduced stem cell properties were associated with lower Sox2 expression. Overexpression of EphA2 promoted stem cell properties in a kinase-independent manner and increased Sox2 expression. Disruption of Akt-EphA2 cross-talk attenuated stem cell marker expression and neurosphere formation while having minimal effects on tumorigenesis. Taken together, the results show that EphA2 endows invasiveness of GSCs in vivo in cooperation with Akt and regulates glioma stem cell properties.Oncogene advance online publication, 3 February 2014; doi:10.1038/onc.2013.590.
    Oncogene 02/2014; DOI:10.1038/onc.2013.590 · 8.56 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Many studies are uncovering functional roles for long noncoding RNAs (lncRNAs), yet few have been tested for in vivo relevance through genetic ablation in animal models. To investigate the functional relevance of lncRNAs in various physiological conditions, we have developed a collection of 18 lncRNA knockout strains in which the locus is maintained transcriptionally active. Initial characterization revealed peri- and postnatal lethal phenotypes in three mutant strains (Fendrr, Peril, and Mdgt), the latter two exhibiting incomplete penetrance and growth defects in survivors. We also report growth defects for two additional mutant strains (linc-Brn1b and linc-Pint). Further analysis revealed defects in lung, gastrointestinal tract, and heart in Fendrr(-/-) neonates, whereas linc-Brn1b(-/-) mutants displayed distinct abnormalities in the generation of upper layer II-IV neurons in the neocortex. This study demonstrates that lncRNAs play critical roles in vivo and provides a framework and impetus for future larger-scale functional investigation into the roles of lncRNA molecules.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: eLife digest The mammalian genome is comprised of DNA sequences that contain the templates for proteins, and other DNA sequences that do not code for proteins. The coding DNA sequences are transcribed to make messenger RNA molecules, which are then translated to make proteins. Researchers have known for many years that some of the noncoding DNA sequences are also transcribed to make other types of RNA molecules, such as transfer and ribosomal RNA. However, the true breadth and diversity of the roles played by these other RNA molecules have only recently begun to be fully appreciated. Mammalian genomes contain thousands of noncoding DNA sequences that are transcribed. Recent in vitro studies suggest that the resulting long noncoding RNA molecules can act as regulators of transcription, translation, and cell cycle. In vitro studies also suggest that these long noncoding RNA molecules may play a role in mammalian development and disease. Yet few in vivo studies have been performed to support or confirm such hypotheses. Now Sauvageau et al. have developed several lines of knockout mice to investigate a subset of noncoding RNA molecules known as long intergenic noncoding RNAs (lincRNAs). These experiments reveal that lincRNAs have a strong influence on the overall viability of mice, and also on a number of developmental processes, including the development of lungs and the cerebral cortex. Given that the vast majority of the human genome is transcribed, the mouse models developed by Sauvageau et al. represent an important step in determining the physiological relevance, on a genetic level, of the noncoding portion of the genome in vivo. DOI: http://dx.doi.org/10.7554/eLife.01749.002
    eLife Sciences 12/2013; 2:e01749. DOI:10.7554/eLife.01749 · 8.52 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Nonalcoholic fatty liver disease is the most common chronic liver disorder in developed countries. Its pathogenesis is poorly understood, and therapeutic options are limited. Here, we show that SIRT7, an NAD(+)-dependent H3K18Ac deacetylase, functions at chromatin to suppress ER stress and prevent the development of fatty liver disease. SIRT7 is induced upon ER stress and is stabilized at the promoters of ribosomal proteins through its interaction with the transcription factor Myc to silence gene expression and to relieve ER stress. SIRT7-deficient mice develop chronic hepatosteatosis resembling human fatty liver disease. Myc inactivation or pharmacological suppression of ER stress alleviates fatty liver caused by SIRT7 deficiency. Importantly, SIRT7 suppresses ER stress and reverts the fatty liver disease in diet-induced obese mice. Our study identifies SIRT7 as a cofactor of Myc for transcriptional repression and delineates a druggable regulatory branch of the ER stress response that prevents and reverts fatty liver disease.
    Cell Reports 11/2013; DOI:10.1016/j.celrep.2013.10.007 · 7.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Angiopoietin-like protein (ANGPTL)8 (alternatively called TD26, RIFL, Lipasin, and Betatrophin) is a newly recognized ANGPTL family member that has been implicated in both triglyceride (TG) and glucose metabolism. Hepatic overexpression of ANGPTL8 causes hypertriglyceridemia and increased insulin secretion. Here we examined the effects of inactivating Angptl8 on TG and glucose metabolism in mice. Angptl8 knockout (Angptl8(-/-)) mice gained weight more slowly than wild-type littermates due to a selective reduction in adipose tissue accretion. Plasma levels of TGs of the Angptl8(-/-) mice were similar to wild-type animals in the fasted state but paradoxically decreased after refeeding. The lower TG levels were associated with both a reduction in very low density lipoprotein secretion and an increase in lipoprotein lipase (LPL) activity. Despite the increase in LPL activity, the uptake of very low density lipoprotein-TG is markedly reduced in adipose tissue but preserved in hearts of fed Angptl8(-/-) mice. Taken together, these data indicate that ANGPTL8 plays a key role in the metabolic transition between fasting and refeeding; it is required to direct fatty acids to adipose tissue for storage in the fed state. Finally, glucose and insulin tolerance testing revealed no alterations in glucose homeostasis in mice fed either a chow or high fat diet. Thus, although absence of ANGPTL8 profoundly disrupts TG metabolism, we found no evidence that it is required for maintenance of glucose homeostasis.
    Proceedings of the National Academy of Sciences 09/2013; DOI:10.1073/pnas.1315292110 · 9.81 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Conditional mutagenesis is becoming a method of choice for studying gene function, but constructing conditional alleles is often laborious, limited by target gene structure, and at times, prone to incomplete conditional ablation. To address these issues, we developed a technology termed conditionals by inversion (COIN). Before activation, COINs contain an inverted module (COIN module) that lies inertly within the antisense strand of a resident gene. When inverted into the sense strand by a site-specific recombinase, the COIN module causes termination of the target gene's transcription and simultaneously provides a reporter for tracking this event. COIN modules can be inserted into natural introns (intronic COINs) or directly into coding exons as part of an artificial intron (exonic COINs), greatly simplifying allele design and increasing flexibility over previous conditional KO approaches. Detailed analysis of over 20 COIN alleles establishes the reliability of the method and its broad applicability to any gene, regardless of exon-intron structure. Our extensive testing provides rules that help ensure success of this approach and also explains why other currently available conditional approaches often fail to function optimally. Finally, the ability to split exons using the COIN's artificial intron opens up engineering modalities for the generation of multifunctional alleles.
    Proceedings of the National Academy of Sciences 08/2013; DOI:10.1073/pnas.1217812110 · 9.81 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: AIMS: Given the impact of vascular injuries and oedema on brain damage caused during stroke, vascular protection represents a major medical need. We hypothesized that angiopoietin-like 4 (ANGPTL4), a regulator of endothelial barrier integrity, might exert a protective effect during ischaemic stroke. METHODS AND RESULTS: Using a murine transient ischaemic stroke model, treatment with recombinant ANGPTL4 led to significantly decreased infarct size and improved behaviour. Quantitative characteristics of the vascular network (density and branchpoints) were preserved in ANGPTL4-treated mice. Integrity of tight and adherens junctions was also quantified and ANGPTL4-treated mice displayed increased VE-cadherin and claudin-5-positive areas. Brain oedema was thus significantly decreased in ANGPTL4-treated mice. In accordance, vascular damage and infarct severity were increased in angptl4-deficient mice thus providing genetic evidence that ANGPTL4 preserves brain tissue from ischaemia-induced alterations. Altogether, these data show that ANGPTL4 protects not only the global vascular network, but also interendothelial junctions and controls both deleterious inflammatory response and oedema.Mechanistically, ANGPTL4 counteracted VEGF signalling and thereby diminished Src-signalling downstream from VEGFR2. This led to decreased VEGFR2-VE-cadherin complex disruption, increased stability of junctions and thus increased endothelial cell barrier integrity of the cerebral microcirculation. In addition, ANGPTL4 prevented neuronal loss in the ischaemic area. CONCLUSION: These results, therefore, show ANGPTL4 counteracts the loss of vascular integrity in ischaemic stroke, by restricting Src kinase signalling downstream from VEGFR2. ANGPTL4 treatment thus reduces oedema, infarct size, neuronal loss, and improves mice behaviour. These results suggest that ANGPTL4 constitutes a relevant target for vasculoprotection and cerebral protection during stroke.
    European Heart Journal 05/2013; DOI:10.1093/eurheartj/eht153 · 14.72 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Skin wound repair requires complex and highly coordinated interactions between keratinocytes, fibroblasts, and immune cells to restore the epidermal barrier and tissue architecture after acute injury. The cytokine IL-22 mediates unidirectional signaling from immune cells to epithelial cells during injury of peripheral tissues such as the liver and colon, where IL-22 causes epithelial cells to produce antibacterial proteins, express mucins, and enhance epithelial regeneration. In this study, we used IL-22(-/-) mice to investigate the in vivo role for IL-22 in acute skin wounding. We found that IL-22(-/-) mice displayed major defects in the skin's dermal compartment after full-thickness wounding. We also found that IL-22 signaling is active in fibroblasts, using in vitro assays with primary fibroblasts, and that IL-22 directs extracellular matrix (ECM) gene expression and myofibroblast differentiation both in vitro and in vivo. These data define roles of IL-22 beyond epithelial cross talk, and suggest that IL-22 has a previously unidentified role in skin repair by mediating interactions between immune cells and fibroblasts.Journal of Investigative Dermatology advance online publication, 6 December 2012; doi:10.1038/jid.2012.463.
    Journal of Investigative Dermatology 12/2012; 133(5). DOI:10.1038/jid.2012.463 · 6.37 Impact Factor
  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Angiopoietin-like proteins (ANGPTLs) play major roles in the trafficking and metabolism of lipids. Inactivation of ANGPTL3, a gene located in an intron of DOCK7, results in very low levels of LDL-cholesterol (C), HDL-C and triglyceride (TAG). We identified another ANGPTL family member, ANGPTL8, which is located in the corresponding intron of DOCK6. A variant in this family member (rs2278426, R59W) was associated with lower plasma LDL-C and HDL-C levels in three populations. ANGPTL8 is expressed in liver and adipose tissue, and circulates in plasma of humans. Expression of ANGPTL8 was reduced by fasting and increased by refeeding in both mice and humans. To examine the functional relationship between the two ANGPTL family members, we expressed ANGPTL3 at physiological levels alone or together with ANGPTL8 in livers of mice. Plasma TAG level did not change in mice expressing ANGPTL3 alone, whereas coexpression with ANGPTL8 resulted in hypertriglyceridemia, despite a reduction in circulating ANGPTL3. ANGPTL8 coimmunoprecipitated with the N-terminal domain of ANGPTL3 in plasma of these mice. In cultured hepatocytes, ANGPTL8 expression increased the appearance of N-terminal ANGPTL3 in the medium, suggesting ANGPTL8 may activate ANGPTL3. Consistent with this scenario, expression of ANGPTL8 in Angptl3(-/-) mice failed to promote hypertriglyceridemia. Thus, ANGPTL8, a paralog of ANGPTL3 that arose through duplication of an ancestral DOCK gene, regulates postprandial TAG and fatty acid metabolism by controlling activation of its progenitor, and perhaps other ANGPTLs. Inhibition of ANGPTL8 provides a new therapeutic strategy for reducing plasma lipoprotein levels.
    Proceedings of the National Academy of Sciences 11/2012; DOI:10.1073/pnas.1217552109 · 9.81 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Chronic mucosal inflammation and tissue damage predisposes patients to the development of colorectal cancer (CRC)1. This association could be explained by the hypothesis that the same factors and pathways important for wound healing also promote tumorigenesis. A sensor of tissue damage should induce these factors to promote tissue repair and regulate their action to prevent development of cancer. IL-22, a cytokine of the IL-10 superfamily, plays an important role for colonic epithelial cell repair, and is increased in the blood and intestine of IBD patients2, 3. This cytokine can be neutralized by the soluble IL-22 receptor, known as the IL-22 binding protein (IL-22BP, IL-22RA2), however the significance of endogenous IL-22BP in vivo and the pathways that regulate this receptor are unknown4, 5. We describe herein that IL-22BP plays a crucial role in controlling tumorigenesis and epithelial cell proliferation in the colon. IL-22BP is highly expressed by dendritic cells (DC) in the colon in steady state conditions. Sensing of intestinal tissue damage via the NLRP3 or NLRP6 inflammasomes led to an IL-18-dependent down regulation of IL-22BP, thereby increasing the ratio of IL-22/IL-22BP. IL-22, which is induced during intestinal tissue damage, exerted protective properties during the peak of damage, but promoted tumor development if uncontrolled during the recovery phase. Thus the IL-22-IL-22BP axis critically regulates intestinal tissue repair and tumorigenesis in the colon.
    Nature 10/2012; 491(7423). DOI:10.1038/nature11535 · 42.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In 2007, the International Knockout Mouse Consortium (IKMC) made the ambitious promise to generate mutations in virtually every protein-coding gene of the mouse genome in a concerted worldwide action. Now, 5 years later, the IKMC members have developed high-throughput gene trapping and, in particular, gene-targeting pipelines and generated more than 17,400 mutant murine embryonic stem (ES) cell clones and more than 1,700 mutant mouse strains, most of them conditional. A common IKMC web portal ( www.knockoutmouse.org ) has been established, allowing easy access to this unparalleled biological resource. The IKMC materials considerably enhance functional gene annotation of the mammalian genome and will have a major impact on future biomedical research.
    Mammalian Genome 09/2012; 23(9-10):580-6. DOI:10.1007/s00335-012-9422-2 · 2.88 Impact Factor
  • Zeitschrift für Gastroenterologie 08/2012; 50(08). DOI:10.1055/s-0032-1324117 · 1.67 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: T-cell immunoglobulin mucin-1 (Tim-1) is a transmembrane protein postulated to be a key regulator of Th2-type immune responses. This hypothesis is based in part upon genetic studies associating Tim-1 polymorphisms in mice with a bias toward airway hyperrespon-siveness (AHR) and the development of Th2-type CD4(+) T cells. Tim-1 expressed by Th2 CD4(+) T cells has been proposed to function as a co-stimulatory molecule. Tim-1 is also expressed by B cells, macrophages, and dendritic cells, but its role in responses by these cell types has not been firmly established. Here, we generated Tim-1-deficient mice to determine the role of Tim-1 in a murine model of allergic airway disease that depends on the development and function of Th2 effector cells and results in the generation of AHR. We found antigen-driven recruitment of inflammatory cells into airways is increased in Tim-1-deficient mice relative to WT mice. In addition, we observed increased antigen-specific cytokine production by splenocytes from antigen-sensitized Tim-1-deficient mice relative to those from controls. These data support the conclusion that Tim-1 functions in pathways that suppress recruitment of inflammatory cells into the airways and the generation or activity of CD4(+) T cells.
    European Journal of Immunology 03/2012; 42(3):651-61. DOI:10.1002/eji.201141581 · 4.52 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A r t i c l e s Proteasomes are vital in generating peptides for presentation on MHC class I molecules 1 . Each proteasome consists of 14 structural subunits and 6 catalytic subunits (two each of the β1, β2 and β5 subunits) 2 . In addition to these three catalytic subunits, three alternative catalytic subunits denoted β1i (LMP2 or Psmb9), β2i (MECL1 or Psmb10) and β5i (LMP7 or Psmb8) are constitutively expressed in a number of hematopoietic cells and are induced in other cell types by interferon-γ (IFN-γ) 2,3 . When expressed, these alternative subunits are preferen-tially incorporated into newly assembling complexes to form immuno-proteasomes 3 and change the catalytic activities of these complexes. Compared with the constitutive proteasomes, immunoproteasomes cleave more rapidly after hydrophobic and basic amino acid residues and less rapidly after acidic ones 4–6 . As peptides with hydrophobic or sometimes basic C termini preferentially bind to MHC class I mol-ecules 7 , it has long been suggested that immunoproteasomes have a specialized role in creating antigenic peptides. However, mice lacking individual immunoproteasome catalytic subunits have relatively modest changes in antigen presentation. For example, β5i-deficient mice have moderately (~50%) lower MHC class I surface expression 8 and lower or higher efficiency in presenting only a few epitopes, whereas the majority of immunogenic peptides examined are pre-sented normally 8–15 . The published analyses have examined only the presentation of known epitopes, and it is unknown whether and how often immunoproteasome-deficient mice present different peptides compared with wild-type mice. To determine whether the modest changes in these mice were due to some contribution from the remaining immunoproteasome catalytic subunits, we created a mouse that was triply deficient, lacking all three immune subunits. Because the genes encoding β1i (Psmb9) and β5i (Psmb8) are so close together on chromosome 17, which made the chance of generating a doubly deficient mouse by crossing β5i-null with β1i-null mice vanishingly small, we chose to create a new sequential deletion of these two genes. We then bred the β1i and β5i doubly deficient mice to β2i-deficient (Psmb10-null) mice to create the animal with a triple immunoproteasome deficiency. We found that the triply deficient mice had altered presentation of most of the epitopes we tested, both in vitro and in vivo, and that these changes in antigen presentation were sufficient to cause triply deficient mice to reject wild-type cells. RESULTS Generation of immunoproteasome–triply deficient mice To generate the β1i β5i doubly deficient animals, we designed a sequential deletion strategy (Fig. 1a). First a LacZ-FRT-neo-FRT construct was fused in frame to the start codon (27 base pairs (bp) downstream of the 5′ end of exon 1) of Psmb8 (which encodes β5i), removing the remainder of exon 1 plus exons 2 through 5 by homolo-gous recombination. The neo gene was then removed by enhanced FLP recombinase (FLPe) activity in the bacteria. An alkaline phosphatase–loxP-neo-loxP construct was then fused in frame to the
    Nature Immunology 02/2012; · 24.97 Impact Factor

Publication Stats

12k Citations
1,274.46 Total Impact Points


  • 1991–2015
    • Regeneron
      Terryville, New York, United States
  • 2012
    • Wellcome Trust Sanger Institute
      Cambridge, England, United Kingdom
  • 2011
    • Collège de France
      • Center for Interdisciplinary Research in Biology
      Lutetia Parisorum, Île-de-France, France
  • 2010
    • Centre d'Immunologie de Marseille-Luminy
      Marsiglia, Provence-Alpes-Côte d'Azur, France
  • 2007
    • Weill Cornell Medical College
      • Department of Genetic Medicine
      New York City, NY, United States
  • 2003
    • Technische Universität Dresden
      Dresden, Saxony, Germany
  • 1995
    • University of Chicago
      Chicago, Illinois, United States
    • University of Zurich
      • The KEY Institute for Brain-Mind Research
      Zürich, Zurich, Switzerland