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2.  Randomized Phase 3 Trial of Abiraterone Acetate in Men with Metastatic Castration-Resistant Prostate Cancer and No Prior Chemotherapy 
The New England journal of medicine  2012;368(2):138-148.
Background
Abiraterone acetate, an androgen biosynthesis inhibitor, improves overall survival (OS) in metastatic castration-resistant prostate cancer (mCRPC) post-chemotherapy. Many mCRPC patients never receive chemotherapy and thus cannot benefit from abiraterone acetate; we evaluated this agent in mCRPC patients who had not received chemotherapy.
Methods
In this double-blind study, 1088 patients were randomized 1:1 to abiraterone acetate (1000 mg) plus prednisone (5 mg twice daily) or placebo plus prednisone. Co-primary end points were radiographic progression-free survival (rPFS) and OS. Secondary end points measured clinically relevant landmarks of mCRPC progression. Patient-reported outcomes included pain progression and quality of life.
Results
The study was unblinded after a planned interim analysis (IA) at 43% of OS events. Treatment with abiraterone acetate-prednisone resulted in a 57% reduction in the risk of radiographic progression or death (hazard ratio [HR], 0.43; 95% confidence interval [CI]: 0.35 to 0.52; P<0.001; 13% OS events IA) and an estimated 25% decrease in the risk of death (HR, 0.75; 95% CI: 0.61 to 0.93; P=0.009; 43% OS events IA). Secondary end points supported superiority of abiraterone acetate-prednisone: time to cytotoxic chemotherapy initiation, opiate use for cancer-related pain, prostate-specific antigen progression (all P<0.001) and performance status deterioration (P=0.005). Self-reported time to pain progression and patient functional status degradation favored abiraterone acetate-prednisone (P=0.05 and P=0.003). Grade 3/4 mineralocorticoid-related adverse events and liver function test abnormalities were more common with abiraterone acetate-prednisone.
Conclusions
Abiraterone acetate produces OS and rPFS benefits, as well as significant delays in clinical deterioration and initiation of chemotherapy, in mCRPC.
doi:10.1056/NEJMoa1209096
PMCID: PMC3683570  PMID: 23228172
Abiraterone acetate; prednisone; metastatic castration-resistant prostate cancer; androgen; CYP17
3.  Consensus Treatments for Moderate Juvenile Dermatomyositis: Beyond the First Two Months 
Arthritis care & research  2012;64(4):546-553.
Objectives
To use consensus methods and the considerable expertise contained within the Children’s Arthritis and Rheumatology Research Alliance (CARRA) organization, to extend the 3 previously developed treatment plans for moderate juvenile dermatomyositis (JDM) to span the full course of treatment.
Methods
A consensus meeting was held in Chicago on April 23–24, 2010 involving 30 pediatric rheumatologists and 4 lay participants. Nominal group technique was used to achieve consensus on treatment plans which represented typical management of moderate JDM. A pre-conference survey of CARRA, completed by 151/272 (56%) members, was used to provide additional guidance to discussion.
Results
Consensus was reached on timing and rate of steroid tapering, duration of steroid therapy, and actions to be taken if patients were unchanged, worsening, experiencing medication side effects or disease complications. Of particular importance, a single, consensus steroid taper was developed.
Conclusions
We were able to develop consensus treatment plans which describe therapy for moderate JDM throughout the treatment course. These treatment plans can now be used clinically, and data collected prospectively regarding treatment effectiveness and toxicity. This will allow comparison of these treatment plans and facilitate the development of evidence-based treatment recommendations for moderate JDM.
doi:10.1002/acr.20695
PMCID: PMC3315594  PMID: 22076847
4.  Treatment of scleromyxedema with IVIg 
doi:10.1186/1546-0096-10-S1-A97
PMCID: PMC3403064
5.  Identification of a Novel C16orf57 Mutation in Athabaskan Patients with Poikiloderma with Neutropenia 
Poikiloderma with Neutropenia (PN), Clericuzio-Type (OMIM #604173) is characterized by poikiloderma, chronic neutropenia, recurrent sinopulmonary infections, bronchiectasis, and nail dystrophy. First described by Clericuzio in 1991 in 14 patients of Navajo descent, it has since also been described in non-Navajo patients. C16orf57 has recently been identified as a causative gene in PN. The purpose of our study was to describe a spectrum of C16orf57 mutations in a cohort of PN patients including five patients of Athabaskan (Navajo and Apache) ancestry. Eleven patients from eight kindreds were enrolled in an IRB-approved study at Baylor College of Medicine. Five patients were of Athabaskan ancestry. PCR amplification and sequencing of the entire coding region of the C16orf57 gene was performed on genomic DNA. We identified biallelic C16orf57 mutations in all eleven PN patients in our cohort. The seven new deleterious mutations consisted of deletion (2), nonsense (3), and splice site (2) mutations. The patients of Athabaskan ancestry all had a common deletion mutation (c.496delA) which was not found in the six non-Athabaskan patients. Mutations in the C16orf57 gene have been identified thus far in all patients studied with a clinical diagnosis of PN. We have identified seven new mutations in C16orf57 in PN patients. One of these is present in all patients of Athabaskan descent, suggesting that c.496delA represents the PN-causative mutation in this subpopulation.
doi:10.1002/ajmg.a.33807
PMCID: PMC3069503  PMID: 21271650
Poikiloderma; Neutropenia; C16orf57; Athabaskan; Navajo; Bronchiectasis; Rothmund-Thomson Syndrome; RECQL4; Mutation
6.  Biologic similarities based on age at onset in oligoarticular and polyarticular subtypes of juvenile idiopathic arthritis 
Arthritis and rheumatism  2010;62(11):3249-3258.
Objective
To explore biologic correlates to age at onset in patients with juvenile idiopathic arthritis (JIA) using peripheral blood mononuclear cell (PBMC) gene expression analysis.
Methods
PBMCs were isolated from 56 healthy controls and 104 patients with recent-onset JIA (39 with persistent oligoarticular JIA, 45 with rheumatoid factor–negative polyarticular JIA, and 20 with systemic JIA). RNA was amplified and labeled using NuGEN Ovation, and gene expression was assessed with Affymetrix HG-U133 Plus 2.0 GeneChips.
Results
A total of 832 probe sets revealed gene expression differences (false discovery rate 5%) in PBMCs from children with oligoarticular JIA whose disease began before age 6 years (early-onset disease) compared with those whose disease began at or after age 6 years (late-onset disease). In patients with early-onset disease, there was greater expression of genes related to B cells and less expression of genes related to cells of the myeloid lineage. Support vector machine analyses identified samples from patients with early- or late-onset oligoarticular JIA (with 97% accuracy) or from patients with early- or late-onset polyarticular JIA (with 89% accuracy), but not from patients with systemic JIA or healthy controls. Principal components analysis showed that age at onset was the major classifier of samples from patients with oligoarticular JIA and patients with polyarticular JIA.
Conclusion
PBMC gene expression analysis reveals biologic differences between patients with early-and late-onset JIA, independent of classification based on the number of joints involved. These data suggest that age at onset may be an important parameter to consider in JIA classification. Furthermore, pathologic mechanisms may vary with age at onset, and understanding these processes may lead to improved treatment of JIA.
doi:10.1002/art.27657
PMCID: PMC3018072  PMID: 20662067
7.  Gene Expression Profiles from Peripheral Blood Mononuclear Cells Are Sensitive to Short Processing Delays 
Biopreservation and biobanking  2010;8(3):153-162.
In the analysis of peripheral blood gene expression, timely processing of samples is essential to ensure that measurements reflect in vivo biology, rather than ex vivo sample processing variables. The effect of processing delays on global gene expression patterns in peripheral blood mononuclear cells (PBMCs) was assessed by isolating and stabilizing PBMC-derived RNA from 3 individuals either immediately after phlebotomy or after a 4 h delay. RNA was labeled using NuGEN Ovation labeling and probed using the Affymetrix HG U133 Plus 2.0 GeneChip®. Comparison of gene expression levels (≥2-fold expression change and P < 0.05) identified 307 probe sets representing genes with increased expression and 46 indicating decreased expression after 4 h. These differentially expressed genes include many that are important to inflammatory, immunologic, and cancer pathways. Among others, CCR2, CCR5, TLR10, CD180, and IL-16 have decreased expression, whereas VEGF, IL8, SOCS2, SOCS3, CD69, and CD83 have increased expression after a 4 h processing delay. The trends in expression patterns associated with delayed processing were also apparent in an independent set of 276 arrays of RNA from human PBMC samples with varying processing times. These data indicate that the time between sample acquisition, initiation of processing, and when the RNA is stabilized should be a prime consideration when designing protocols for translational studies involving PBMC gene expression analysis.
doi:10.1089/bio.2010.0009
PMCID: PMC3129811  PMID: 21743826
8.  Gene Expression Profiles from Peripheral Blood Mononuclear Cells Are Sensitive to Short Processing Delays 
Biopreservation and Biobanking  2010;8(3):153-162.
In the analysis of peripheral blood gene expression, timely processing of samples is essential to ensure that measurements reflect in vivo biology, rather than ex vivo sample processing variables. The effect of processing delays on global gene expression patterns in peripheral blood mononuclear cells (PBMCs) was assessed by isolating and stabilizing PBMC-derived RNA from 3 individuals either immediately after phlebotomy or after a 4 h delay. RNA was labeled using NuGEN Ovation labeling and probed using the Affymetrix HG U133 Plus 2.0 GeneChip®. Comparison of gene expression levels (≥2-fold expression change and P < 0.05) identified 307 probe sets representing genes with increased expression and 46 indicating decreased expression after 4 h. These differentially expressed genes include many that are important to inflammatory, immunologic, and cancer pathways. Among others, CCR2, CCR5, TLR10, CD180, and IL-16 have decreased expression, whereas VEGF, IL8, SOCS2, SOCS3, CD69, and CD83 have increased expression after a 4 h processing delay. The trends in expression patterns associated with delayed processing were also apparent in an independent set of 276 arrays of RNA from human PBMC samples with varying processing times. These data indicate that the time between sample acquisition, initiation of processing, and when the RNA is stabilized should be a prime consideration when designing protocols for translational studies involving PBMC gene expression analysis.
doi:10.1089/bio.2010.0009
PMCID: PMC3129811  PMID: 21743826
9.  Curcuminoids Activate p38 Map Kinases and Promote UVB-Dependent Signaling in Keratinocytes 
Experimental dermatology  2010;19(6):493-500.
Curcuminoids exhibit anti-proliferative properties in many cell lines by modulating signaling pathways to inhibit cell growth. However, the specific effects of curcuminoids on human keratinocytes are not well defined, and this situation impairs mechanistic thinking regarding potential therapeutic uses. We hypothesized that curcuminoids would modulate key growth regulatory pathways in keratinocytes to inhibit cell proliferation. To test this hypothesis, the effects of curcumin and tetrahydrocurcumin (THC) on MAP kinase signaling in keratinoctyes were determined.
Primary human keratinocytes treated with curcumin or THC demonstrated decreased activation of p44/42 MAP kinases but increased levels of activated p38 MAP kinases. These data suggest that curcuminoids specifically activate stress-induced MAP kinases while inhibiting mitogen-induced MAP kinases. Curcuminoids also promote the phosphorylation of p53 on serine 15 in a dose-dependent and p38-dependent manner, suggesting that these compounds may activate p53. The effects of curcuminoids on keratinocytes mirrored some aspects of UVB and could be inhibited by N-acetylcysteine, suggesting that these compounds activate p38 through a mechanism that involves glutathione depletion. Both curcuminoids induced G2/M block and inhibited keratinocyte growth, and THC increased cellular levels of p21, a known p53 transcriptional target.
These data demonstrate that curcuminoids can differentially regulate MAP kinases to inhibit keratinocyte growth while inducing p21. Curcuminoids also synergize with UVB to enhance p53 phosphorylation. The findings provide a rationale for testing curcuminoids in disorders associated with impaired p53 function or in which UVB-treatment is efficacious.
doi:10.1111/j.1600-0625.2010.01081.x
PMCID: PMC3099406  PMID: 20456495
Curcumin; keratinocytes; MAP kinases; p53; UVB
10.  Unexpected Role for the Immunoproteasome Subunit LMP2 in Antiviral Humoral and Innate Immune Responses 
Proteasomes are multisubunit proteases that initiate degradation of many Ags presented by MHC class I molecules. Vertebrates express alternate forms of each of the three catalytic proteasome subunits: standard subunits, and immunosubunits, which are constitutively expressed by APCs and are induced in other cell types by exposure to cytokines. The assembly of mixed proteasomes containing standard subunits and immunosubunits is regulated in a tissue specific manner. In this study, we report that the presence of mixed proteasomes in immune cells in LMP2−/− mice compromises multiple components that contribute to the generation of antiviral Ab responses, including splenic B cell numbers, survival and function of adoptively transferred B cells, Th cell function, and dendritic cell secretion of IL-6, TNF-α, IL-1β, and type I IFNs. These defects did not result from compromised overall protein degradation, rather they were associated with altered NF-κB activity. These findings demonstrate an important role for immunoproteasomes in immune cell function beyond their contribution to Ag processing.
doi:10.4049/jimmunol.0903003
PMCID: PMC2941094  PMID: 20228196
11.  Srcasm inhibits Fyn-induced cutaneous carcinogenesis with modulation of Notch 1 and p53 
Cancer research  2009;69(24):9439-9447.
Src-family tyrosine kinases (SFKs) regulate cell proliferation, and increased SFK activity is common in human carcinomas, including cutaneous squamous cell carcinomas and its precursors. The elevated SFK activity in cutaneous SCCs was modeled using keratin 14-Fyn Y528F transgenic mice, which spontaneously form punctate keratotic lesions, scaly plaques, and large tumors resembling actinic keratoses (AKs), carcinoma in situ (SCIS), and SCCs, respectively.
Lesional tissue demonstrated increased levels of activated SFKs, PDK-1, STAT-3, and Erk1/2 while Notch 1/NICD protein and transcript levels were decreased. p53 levels also were decreased in SCIS and SCCs.
Raising Srcasm levels using a K14-Fyn Y528F/K14-Srcasm double transgenic model markedly inhibited cutaneous neoplasia. In contrast, increased expression of a non-phosphorylatable Srcasm mutant maintained the neoplastic phenotype. Raising Srcasm levels decreased levels of Fyn, activated SFKs, Erk 1/2, PDK-1, and phospho-STAT3, and raised Notch 1/NICD and p53 levels.
Analysis of human specimens revealed that levels of Fyn and activated SFKs were elevated in SCCs compared with adjacent non-lesional epidermis. In addition, Notch 1 and Srcasm protein and transcript levels were decreased in human SCCs compared to non-lesional epidermis. Therefore, the SCCs produced by the Fyn Y528F mice resemble their human counterparts at the molecular level.
K14-Fyn Y528F mice represent a robust model of cutaneous carcinogenesis that manifests precancerous lesions and SCCs resembling human disease. The Fyn/Srcasm signaling nexus modulates activity of STAT-3, PDK-1, Erk 1/2, Notch 1 and p53. Further study of Fyn and Srcasm should provide insights into the mechanisms regulating keratinocyte proliferation and skin carcinogenesis.
doi:10.1158/0008-5472.CAN-09-2976
PMCID: PMC2794931  PMID: 19934324
12.  Gene Expression Signatures in Polyarticular Juvenile Idiopathic Arthritis Demonstrate Disease Heterogeneity and Offer a Molecular Classification of Disease Subsets 
Arthritis and rheumatism  2009;60(7):2113-2123.
Objective
Microarray analysis was used to determine whether children with recent onset polyarticular juvenile idiopathic arthritis (JIA) exhibit biologically or clinically informative gene expression signatures in peripheral blood mononuclear cells (PBMC).
Methods
Peripheral blood samples were obtained from 59 healthy children and 61 children with polyarticular JIA prior to treatment with second-line medications, such as methotrexate or biological agents. RNA was extracted from Ficoll-isolated mononuclear cells, fluorescently labeled and hybridized to Affymetrix U133 Plus 2.0 GeneChips. Data were analyzed using ANOVA at a 5% false discovery rate threshold after Robust Multi-Array Average pre-processing and Distance Weighted Discrimination normalization.
Results
Initial analysis revealed 873 probe sets for genes that were differentially expressed between polyarticular JIA and controls. Hierarchical clustering of these probe sets distinguished three subgroups within polyarticular JIA. Prototypical subjects within each subgroup were identified and used to define subgroup-specific gene expression signatures. One of these signatures was associated with monocyte markers, another with transforming growth factor β-inducible genes, and a third with immediate-early genes. Correlation of gene expression signatures with clinical and biological features of JIA subgroups suggests relevance to aspects of disease activity and supports the division of polyarticular JIA into distinct subsets.
Conclusions
PBMC gene expression signatures in recent onset polyarticular JIA reflect discrete disease processes and offer a molecular classification of disease.
doi:10.1002/art.24534
PMCID: PMC2741130  PMID: 19565504
13.  Immature cell populations and an erythropoiesis gene-expression signature in systemic juvenile idiopathic arthritis: implications for pathogenesis 
Arthritis Research & Therapy  2010;12(3):R123.
Introduction
Previous observations suggest that active systemic juvenile idiopathic arthritis (sJIA) is associated with a prominent erythropoiesis gene-expression signature. The aim of this study was to determine the association of this signature with peripheral blood mononuclear cell (PBMC) subpopulations and its specificity for sJIA as compared with related conditions.
Methods
The 199 patients with JIA (23 sJIA and 176 non-sJIA) and 38 controls were studied. PBMCs were isolated and analyzed for multiple surface antigens with flow cytometry and for gene-expression profiles. The proportions of different PBMC subpopulations were compared among sJIA, non-sJIA patients, and controls and subsequently correlated with the strength of the erythropoiesis signature. Additional gene-expression data from patients with familial hemophagocytic lymphohistiocytosis (FHLH) and from a published sJIA cohort were analyzed to determine whether the erythropoiesis signature was present.
Results
Patients with sJIA had significantly increased proportions of immature cell populations, including CD34+ cells, correlating highly with the strength of the erythropoiesis signature. The erythropoiesis signature strongly overlapped with the gene-expression pattern in purified immature erythroid precursors. The expansion of immature cells was most prominently seen in patients with sJIA and anemia, even in the absence of reticulocytosis. Patients with non-sJIA and anemia did not exhibit the erythropoiesis signature. The erythropoiesis signature was found to be prominent in patients with FHLH and in a published cohort of patients with active sJIA, but not in patients with inactive sJIA.
Conclusions
An erythropoiesis signature in active sJIA is associated with the expansion of CD34+ cells, also is seen in some patients with FHLH and infection, and may be an indicator of ineffective erythropoiesis and hemophagocytosis due to hypercytokinemia.
doi:10.1186/ar3061
PMCID: PMC2911917  PMID: 20576155
14.  Emerging Role of the CB2 Cannabinoid Receptor in Immune Regulation and Therapeutic Prospects 
There is now a large body of data that indicates that the CB2 cannabinoid receptor type 2 (CB2) is linked to a variety of immune functional events. This functional relevance appears to be most salient in the course of inflammation, a process during which there is an increased number of receptors that are available for activation. Studies aimed at elucidating signal transductional events resulting from CB2 interaction with its native ligands, and of the role of exogenous cannabinoids in modulating this process, are providing novel insights into the role of the CB2 in maintaining a homeostatic immune balance within the host. Furthermore, these studies suggest that the CB2 may serve as a selective molecular target for therapeutic manipulation of untoward immune responses including those associated with a variety of neuropathies that exhibit a hyperinflammatory component.
doi:10.1017/S1462399409000957
PMCID: PMC2768535  PMID: 19152719
AIDS; Alzheimer’s disease; ALS; amyotrophic lateral sclerosis; anandamide; 2-arachidonoylglycerol; cannabinoid receptors; CB2; delta-9-tetrahydrocannabinol; Δ9-THC; endocannabinoids; granulomatous amebic encephalitis; HIV encephalitis; multiple sclerosis; neuroinflammation
15.  Cannabinoids as Therapeutic Agents for Ablating Neuroinflammatory Disease 
Cannabinoids have been reported to alter the activities of immune cells in vitro and in vivo. These compounds may serve as ideal agents for adjunct treatment of pathological processes that have a neuroinflammatory component. As highly lipophilic molecules, they readily access the brain. Furthermore, they have relatively low toxicity and can be engineered to selectively target cannabinoid receptors. To date, two cannabinoid receptors have been identified, characterized and designated CB1 and CB2. CB1 appears to be constitutively expressed within the CNS while CB2 apparently is induced during inflammation. The inducible nature of CB2 extends to microglia, the resident macrophages of the brain that play a critical role during early stages of inflammation in that compartment. Thus, the cannabinoid-cannabinoid receptor system may prove therapeutically manageable in ablating neuropathogenic disorders such as Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis, HIV encephalitis, closed head injury, and granulomatous amebic encephalitis.
PMCID: PMC2750822  PMID: 18782012
Alzheimer’s; amyotrophic lateral sclerosis; cannabinoids; cannabinoid receptors; granulomatous amebic encephalitis; HIV encephalitis; multiple sclerosis; neuroinflammation
16.  Differential intra-proteasome interactions involving standard and immunosubunits 
Animals with immune systems have two types of proteasomes, “standard proteasomes” and “immunoproteasomes” that respectively contain constitutively expressed catalytic subunits or interferon-γ-inducible catalytic subunits. Interestingly, proteasome assembly is biased against formation of most mixed proteasomes containing combinations of standard subunits and immunosubunits. We previously demonstrated that catalytic subunit propeptide differences contribute to this assembly specificity. In the current study, we investigated the contributions of catalytic subunit propeptides and C-terminal extensions to intra-proteasome protein-protein interactions that are potentially involved in mediating biased assembly of human proteasomes, and we found a number of interactions that differentially depended on these structures. For example, the C-terminal extension of standard subunit β2 is required for β2’s interaction with adjacent β3, whereas the C-terminal extension of immunosubunit β2i is dispensable for β2i’s interaction with β3. Taken together, our results suggest mechanisms whereby differential intra-proteasome interactions could contribute to proteasome assembly specificity.
doi:10.1016/j.bbrc.2007.05.011
PMCID: PMC2680721  PMID: 17506986
Proteasome; Immunoproteasome; Proteasome assembly; Propeptide; Protein-protein interaction; Yeast two-hybrid interaction
17.  Potential Impact of Antiviral Drug Use during Influenza Pandemic 
Emerging Infectious Diseases  2005;11(9):1355-1362.
Impact of different antiviral treatment strategies on hospitalizations during an influenza pandemic is evaluated.
The recent spread of highly pathogenic strains of avian influenza has highlighted the threat posed by pandemic influenza. In the early phases of a pandemic, the only treatment available would be neuraminidase inhibitors, which many countries are considering stockpiling for pandemic use. We estimate the effect on hospitalization rates of using different antiviral stockpile sizes to treat infection. We estimate that stockpiles that cover 20%–25% of the population would be sufficient to treat most of the clinical cases and could lead to 50% to 77% reductions in hospitalizations. Substantial reductions in hospitalization could be achieved with smaller antiviral stockpiles if drugs are reserved for persons at high risk.
doi:10.3201/eid1109.041344
PMCID: PMC3371825  PMID: 16229762
Epidemic Modeling; Antiviral treatment; Pandemic Influenza; Public Health Planning; Real Time Modeling; research
18.  In Vitro Transposition System for Efficient Generation of Random Mutants of Campylobacter jejuni 
Journal of Bacteriology  2001;183(7):2384-2388.
Campylobacter jejuni is the most common cause of food-borne illnesses in the United States. Despite the fact that the entire nucleotide sequence of its genome has recently become available, its mechanisms of pathogenicity are poorly understood. This is in part due to the lack of an efficient mutagenesis system. Here we describe an in vitro transposon mutagenesis system based on the Staphylococcus aureus transposable element Tn552 that allows the efficient generation of insertion mutants of C. jejuni. Insertions occur randomly and throughout the entire bacterial genome. We have tested this system in the isolation of nonmotile mutants of C. jejuni. Demonstrating the utility of the system, six nonmotile mutants from a total of nine exhibited insertions in genes known to be associated with motility. An additional mutant had an inactivating insertion in sigma 54, implicating this transcription factor in flagellum regulation. The availability of this efficient system will greatly facilitate the study of the mechanisms of pathogenesis of this important pathogen.
doi:10.1128/JB.183.7.2384-2388.2001
PMCID: PMC95150  PMID: 11244083
19.  Identification of Genes Encoding Exported Mycobacterium tuberculosis Proteins Using a Tn552′phoA In Vitro Transposition System 
Journal of Bacteriology  2000;182(10):2732-2740.
Secreted and cell envelope-associated proteins are important to both Mycobacterium tuberculosis pathogenesis and the generation of protective immunity to M. tuberculosis. We used an in vitro Tn552′phoA transposition system to identify exported proteins of M. tuberculosis. The system is simple and efficient, and the transposon inserts randomly into target DNA. M. tuberculosis genomic libraries were targeted with Tn552′phoA transposons, and these libraries were screened in M. smegmatis for active PhoA translational fusions. Thirty-two different M. tuberculosis open reading frames were identified; eight contain standard signal peptides, six contain lipoprotein signal peptides, and seventeen contain one or more transmembrane domains. Four of these proteins had not yet been assigned as exported proteins in the M. tuberculosis databases. This collection of exported proteins includes factors that are known to participate in the immune response of M. tuberculosis and proteins with homologies, suggesting a role in pathogenesis. Nine of the proteins appear to be unique to mycobacteria and represent promising candidates for factors that participate in protective immunity and virulence. This technology of creating comprehensive fusion libraries should be applicable to other organisms.
PMCID: PMC101980  PMID: 10781540
20.  Immunoproteasome Assembly: Cooperative Incorporation of Interferon γ (IFN-γ)–inducible Subunits  
LMP2, LMP7, and MECL are interferon γ–inducible catalytic subunits of vertebrate 20S proteasomes, which can replace constitutive catalytic subunits (delta, X, and Z, respectively) during proteasome biogenesis. We demonstrate that MECL requires LMP2 for efficient incorporation into preproteasomes, and preproteasomes containing LMP2 and MECL require LMP7 for efficient maturation. The latter effect depends on the presequence of LMP7, but not on LMP7 catalytic activity. This cooperative mechanism favors the assembly of homogeneous “immunoproteasomes” containing all three inducible subunits, suggesting that these subunits act in concert to enhance proteasomal generation of major histocompatibility complex class I–binding peptides.
PMCID: PMC2199179  PMID: 9419215

Results 1-21 (21)