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  • Proceedings of the National Academy of Sciences  (8)
  • 2010-2014  (8)
  • 1
    Online Resource
    Online Resource
    Conditionals by inversion provide a universal method for the generation of conditional alleles
    Proceedings of the National Academy of Sciences ; 2013
    In:  Proceedings of the National Academy of Sciences Vol. 110, No. 34 ( 2013-08-20)
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 110, No. 34 ( 2013-08-20)
    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.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1217812110
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2013
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
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  • 2
    Online Resource
    Online Resource
    Precise and in situ genetic humanization of 6 Mb of mouse immunoglobulin genes
    Proceedings of the National Academy of Sciences ; 2014
    In:  Proceedings of the National Academy of Sciences Vol. 111, No. 14 ( 2014-04-08), p. 5147-5152
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 111, No. 14 ( 2014-04-08), p. 5147-5152
    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.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1323896111
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2014
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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  • 3
    Online Resource
    Online Resource
    Essential role for mast cell tryptase in acute experimental colitis
    Proceedings of the National Academy of Sciences ; 2011
    In:  Proceedings of the National Academy of Sciences Vol. 108, No. 1 ( 2011-01-04), p. 290-295
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 108, No. 1 ( 2011-01-04), p. 290-295
    Abstract: Patients with inflammatory bowel disease (IBD) have increased numbers of human tryptase-β (hTryptase-β)-positive mast cells (MCs) in the gastrointestinal tract. The amino acid sequence of mouse mast cell protease (mMCP)-6 is most similar to that of hTryptase-β. We therefore hypothesized that this mMCP, or the related tryptase mMCP-7, might have a prominent proinflammatory role in experimental colitis. The dextran sodium sulfate (DSS) and trinitrobenzene sulfonic acid (TNBS) colitis models were used to evaluate the differences between C57BL/6 (B6) mouse lines that differ in their expression of mMCP-6 and mMCP-7 with regard to weight loss, colon histopathology, and endoscopy scores. Microarray analyses were performed, and confirmatory real-time PCR, ELISA, and/or immunohistochemical analyses were carried out on a number of differentially expressed cytokines, chemokines, and matrix metalloproteinases (MMPs). The mMCP-6–null mice that had been exposed to DSS had significantly less weight loss as well as significantly lower pathology and endoscopy scores than similarly treated mMCP-6–expressing mice. This difference in colitis severity was confirmed endoscopically in the TNBS-treated mice. Evaluation of the distal colon segments revealed that numerous proinflammatory cytokines, chemokines that preferentially attract neutrophils, and MMPs that participate in the remodeling of the ECM were all markedly increased in the colons of DSS-treated WT mice relative to untreated WT mice and DSS-treated mMCP-6–null mice. Collectively, our data show that mMCP-6 (but not mMCP-7) is an essential MC-restricted mediator in chemically induced colitis and that this tryptase acts upstream of many of the factors implicated in IBD.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1005758108
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2011
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
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  • 4
    Online Resource
    Online Resource
    Human thrombopoietin knockin mice efficiently support human hematopoiesis in vivo
    Proceedings of the National Academy of Sciences ; 2011
    In:  Proceedings of the National Academy of Sciences Vol. 108, No. 6 ( 2011-02-08), p. 2378-2383
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 108, No. 6 ( 2011-02-08), p. 2378-2383
    Abstract: Hematopoietic stem cells (HSCs) both self-renew and give rise to all blood cells for the lifetime of an individual. Xenogeneic mouse models are broadly used to study human hematopoietic stem and progenitor cell biology in vivo. However, maintenance, differentiation, and function of human hematopoietic cells are suboptimal in these hosts. Thrombopoietin (TPO) has been demonstrated as a crucial cytokine supporting maintenance and self-renewal of HSCs. We generated RAG2 −/− γ c −/− mice in which we replaced the gene encoding mouse TPO by its human homolog. Homozygous humanization of TPO led to increased levels of human engraftment in the bone marrow of the hosts, and multilineage differentiation of hematopoietic cells was improved, with an increased ratio of myelomonocytic verus lymphoid lineages. Moreover, maintenance of human stem and progenitor cells was improved, as demonstrated by serial transplantation. Therefore, RAG2 −/− γ c −/− TPO-humanized mice represent a useful model to study human hematopoiesis in vivo.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1019524108
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2011
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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  • 5
    Online Resource
    Online Resource
    Human IL-3/GM-CSF knock-in mice support human alveolar macrophage development and human immune responses in the lung
    Proceedings of the National Academy of Sciences ; 2011
    In:  Proceedings of the National Academy of Sciences Vol. 108, No. 6 ( 2011-02-08), p. 2390-2395
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 108, No. 6 ( 2011-02-08), p. 2390-2395
    Abstract: Mice with a functional human immune system have the potential to allow in vivo studies of human infectious diseases and to enable vaccine testing. To this end, mice need to fully support the development of human immune cells, allow infection with human pathogens, and be capable of mounting effective human immune responses. A major limitation of humanized mice is the poor development and function of human myeloid cells and the absence of human immune responses at mucosal surfaces, such as the lung. To overcome this, we generated human IL-3/GM-CSF knock-in (hIL-3/GM-CSF KI) mice. These mice faithfully expressed human GM-CSF and IL-3 and developed pulmonary alveolar proteinosis because of elimination of mouse GM-CSF. We demonstrate that hIL-3/GM-CSF KI mice engrafted with human CD34 + hematopoietic cells had improved human myeloid cell reconstitution in the lung. In particular, hIL-3/GM-CSF KI mice supported the development of human alveolar macrophages that partially rescued the pulmonary alveolar proteinosis syndrome. Moreover, human alveolar macrophages mounted correlates of a human innate immune response against influenza virus. The hIL-3/GM-CSF KI mice represent a unique mouse model that permits the study of human mucosal immune responses to lung pathogens.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1019682108
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2011
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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    Online Resource
  • 6
    Online Resource
    Online Resource
    Mice with megabase humanization of their immunoglobulin genes generate antibodies as efficiently as normal mice
    Proceedings of the National Academy of Sciences ; 2014
    In:  Proceedings of the National Academy of Sciences Vol. 111, No. 14 ( 2014-04-08), p. 5153-5158
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 111, No. 14 ( 2014-04-08), p. 5153-5158
    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.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1324022111
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2014
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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  • 7
    Online Resource
    Online Resource
    PACAP receptor gene polymorphism impacts fear responses in the amygdala and hippocampus
    Proceedings of the National Academy of Sciences ; 2014
    In:  Proceedings of the National Academy of Sciences Vol. 111, No. 8 ( 2014-02-25), p. 3158-3163
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 111, No. 8 ( 2014-02-25), p. 3158-3163
    Abstract: We have recently found higher circulating levels of pituitary adenylate cyclase-activating polypeptide (PACAP) associated with posttraumatic stress disorder (PTSD) symptoms in a highly traumatized cohort of women but not men. Furthermore, a single nucleotide polymorphism in the PACAP receptor gene ADCYAP1R1 , adenylate cyclase activating polypeptide 1 receptor type 1, was associated with individual differences in PTSD symptoms and psychophysiological markers of fear and anxiety. The current study outlines an investigation of individual differences in brain function associated with ADCYAP1R1 genotype. Forty-nine women who had experienced moderate to high levels of lifetime trauma participated in a functional MRI task involving passive viewing of threatening and neutral face stimuli. Analyses focused on the amygdala and hippocampus, regions that play central roles in the pathophysiology of PTSD and are known to have high densities of PACAP receptors. The risk genotype was associated with increased reactivity of the amygdala and hippocampus to threat stimuli and decreased functional connectivity between the amygdala and hippocampus. The findings indicate that the PACAP system modulates medial temporal lobe function in humans. Individual differences in ADCYAP1R1 genotype may contribute to dysregulated fear circuitry known to play a central role in PTSD and other anxiety disorders.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1318954111
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2014
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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  • 8
    Online Resource
    Online Resource
    The role of intracellular calcium phosphate in osteoblast-mediated bone apatite formation
    Proceedings of the National Academy of Sciences ; 2012
    In:  Proceedings of the National Academy of Sciences Vol. 109, No. 35 ( 2012-08-28), p. 14170-14175
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 109, No. 35 ( 2012-08-28), p. 14170-14175
    Abstract: Mineralization is a ubiquitous process in the animal kingdom and is fundamental to human development and health. Dysfunctional or aberrant mineralization leads to a variety of medical problems, and so an understanding of these processes is essential to their mitigation. Osteoblasts create the nano-composite structure of bone by secreting a collagenous extracellular matrix (ECM) on which apatite crystals subsequently form. However, despite their requisite function in building bone and decades of observations describing intracellular calcium phosphate, the precise role osteoblasts play in mediating bone apatite formation remains largely unknown. To better understand the relationship between intracellular and extracellular mineralization, we combined a sample-preparation method that simultaneously preserved mineral, ions, and ECM with nano-analytical electron microscopy techniques to examine osteoblasts in an in vitro model of bone formation. We identified calcium phosphate both within osteoblast mitochondrial granules and intracellular vesicles that transported material to the ECM. Moreover, we observed calcium-containing vesicles conjoining mitochondria, which also contained calcium, suggesting a storage and transport mechanism. Our observations further highlight the important relationship between intracellular calcium phosphate in osteoblasts and their role in mineralizing the ECM. These observations may have important implications in deciphering both how normal bone forms and in understanding pathological mineralization.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1208916109
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2012
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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