The genome of the marine medaka Oryzias melastigma

Marine medaka (Oryzias melastigma) is considered to be a useful fish model for marine and estuarine ecotoxicology studies and has good potential for field‐based population genomics because of its geographical distribution in Asian estuarine and coastal areas. In this study, we present the first whole‐genome draft of O. melastigma. The genome assembly consists of 8,602 scaffolds (N50 = 23.737 Mb) and a total genome length of 779.4 Mb. A total of 23,528 genes were predicted, and 12,670 gene families shared with three teleost species (Japanese medaka, mangrove killifish and zebrafish) were identified. Genome analyses revealed that the O. melastigma genome is highly heterozygous and contains a large number of repeat sequences. This assembly represents a useful genomic resource for fish scientists.     

Apoptosis signal-regulating kinase 1 regulates the expression of caspase-11

Caspase-11 is an inducible caspase involved in the regulation of cell death and inflammation. In the present study, we examined whether apoptosis signal-regulating kinase 1 (Ask1)-mediated signaling pathway is involved in the expression of caspase-11 induced by lipopolysaccharide (LPS). We found that the induction of caspase-11 was suppressed by the inhibitors of NADPH oxidase (Nox) or knockdown of Nox4 that acts downstream of toll-like receptor 4 and generates Ask1-activating reactive oxygen species. Overexpression of dominant negative tumor necrosis factor receptor associate factor 6 also suppressed the induction of caspase-11. Importantly, knockdown or dominant negative form of Ask1 suppressed the induction of caspase-11 following LPS stimulation. Taken together, our results show that Ask1 regulates the expression of caspase-11 following LPS stimulation.     

Enhancement in the viability and biosensing activity of freeze-dried recombinant bioluminescent bacteria

The genetically-engineeredEscherichia coli strain, DPD2540, which contains afabA::luxCDABE fusion gene, gives a bioluminescent output when membrane fatty acid synthesis is needed. For more practical application of this strain in the field as biosensor, freeze-drying was adopted. A 12% sucrose solution with Luria-Bertani (LB) broth, as determined by the viability after freeze-drying, was found to be the most effective composition for lyophilization solution among various compositions tested. Rapid freezing with liquid nitrogen also gave the best viability after freeze-drying as compared to samples frozen at −70°C and −20°C. The biosensing activities of the cells showed a greater sensitivity when the cells from the exponential phase were freeze-dried. Finally, the optimum temperature for use of the freeze-dried cells in the biosensor field was determined.     

Kaposi's sarcoma-associated herpesvirus OX2 glycoprotein activates myeloid-lineage cells to induce inflammatory cytokine production

Kaposi's sarcoma is an inflammatory cytokine-mediated angioproliferative disease which is triggered by infection by Kaposi's sarcoma-associated herpesvirus (KSHV). KSHV contains an open reading frame, K14, that has significant homology with cellular OX2, designated viral OX2 (vOX2). In this report, we demonstrate that vOX2 encodes a glycosylated cell surface protein with an apparent molecular mass of 55 kDa. Purified glycosylated vOX2 protein dramatically stimulated primary monocytes, macrophages, and dendritic cells to produce the inflammatory cytokines interleukin 1beta (IL-1beta), IL-6, monocyte chemoattractant protein 1, and TNF-alpha. Furthermore, expression of vOX2 on B lymphocytes stimulated monocytes to produce inflammatory cytokines in mixed culture. These results demonstrate that like its cellular counterpart, vOX2 targets myeloid-lineage cells, but unlike cellular OX2, which delivers a restrictive signal, KSHV vOX2 provides an activating signal, resulting in the production of inflammatory cytokines. Thus, this is a novel viral strategy where KSHV has acquired the cellular OX2 gene to induce inflammatory cytokine production, which potentially promotes the cytokine-mediated angiogenic proliferation of KSHV-infected cells.     

Organization and assembly of the TRAPPII complex

Current models suggest that TRAPP tethering complexes exist in two forms. Whereas the seven-subunit TRAPPI complex mediates ER-to-Golgi transport, TRAPPII contains three additional subunits (Trs65, Trs120 and Trs130) and is required for distinct tethering events at Golgi membranes. It is not clear how TRAPPII assembly is regulated. Here, we show that Tca17 is a fourth TRAPPII-specific component, and that Trs65 and Tca17 interact with distinct domains of Trs130 and make different contributions to complex assembly. Whereas Tca17 promotes the stable association of TRAPPII-specific subunits with the core complex, Trs65 stabilizes TRAPPII in an oligomeric form. We show that Trs85, which was previously reported to be a subunit of both TRAPPI and TRAPPII, is not associated with the TRAPPII complex in yeast. However, we find that proteins related to Trs85, Trs65 and Tca17 are part of the same TRAPP complex in mammalian cells. These findings have implications for models of TRAPP complex formation and suggest that TRAPP complexes may be organized differently in yeast and mammals.     

The MHC class I-like IgG receptor controls perinatal IgG transport,IgG homeostasis,and fate of IgG-Fc-coupled drugs

Abs of the IgG isotype are efficiently transported from mother to neonate and have an extended serum t(1/2) compared with Abs of other isotypes. Circumstantial evidence suggests that the MHC class I-related protein, the neonatal FcR (FcRn), is the FcR responsible for both in vivo functions. To understand the phenotypes imposed by FcRn, we produced and analyzed mice with a defective FcRn gene. The results provide direct evidence that perinatal IgG transport and protection of IgG from catabolism are mediated by FcRn, and that the latter function is key to IgG homeostasis, essential for generating a potent IgG response to foreign Ags, and the basis of enhanced efficacy of Fc-IgG-based therapeutics. FcRn is therefore a promising therapeutic target for enhancing protective humoral immunity, treating autoimmune disease, and improving drug efficacy.     

Interaction of Par-6 and Crumbs complexes is essential for photoreceptor morphogenesis in Drosophila

Apicobasal cell polarity is crucial for morphogenesis of photoreceptor rhabdomeres and adherens junctions (AJs) in the Drosophila eye. Crumbs (Crb) is specifically localized to the apical membrane of photoreceptors, providing a positional cue for the organization of rhabdomeres and AJs. We show that the Crb complex consisting of Crb, Stardust (Sdt) and Discs-lost (Dlt) colocalizes with another protein complex containing Par-6 and atypical protein kinase C (aPKC) in the rhabdomere stalk of photoreceptors. Loss of each component of the Crb complex causes age-dependent mislocalization of Par-6 complex proteins, and ectopic expression of Crb intracellular domain is sufficient to recruit the Par-6 complex. We also show that the absence of Par-6 complex proteins results in severe mislocalization and loss of Crb complex. We further demonstrate that Dlt directly binds to Par-6, providing a molecular basis for the mutual dependence of the two complexes. These results suggest that the interaction of Crb and Par-6 complexes is required for the organization and maintenance of apical membranes and AJs of photoreceptors.     

Unique Behavioral Characteristics and microRNA Signatures in a Drug Resistant Epilepsy Model

Background

Pharmacoresistance is a major issue in the treatment of epilepsy. However, the mechanism underlying pharmacoresistance to antiepileptic drugs (AEDs) is still unclear, and few animal models have been established for studying drug resistant epilepsy (DRE). In our study, spontaneous recurrent seizures (SRSs) were investigated by video-EEG monitoring during the entire procedure.

Methods/Principal Findings

In the mouse pilocarpine-induced epilepsy model, we administered levetiracetam (LEV) and valproate (VPA) in sequence. AED-responsive and AED-resistant mice were naturally selected after 7-day treatment of LEV and VPA. Behavioral tests (open field, object exploration, elevated plus maze, and light-dark transition test) and a microRNA microarray test were performed. Among the 37 epileptic mice with SRS, 23 showed significantly fewer SRSs during administration of LEV (n = 16, LEV sensitive (LS) group) or VPA (n = 7, LEV resistant/VPA sensitive (LRVS) group), while 7 epileptic mice did not show any amelioration with either of the AEDs (n = 7, multidrug resistant (MDR) group). On the behavioral assessment, MDR mice displayed distinctive behaviors in the object exploration and elevated plus maze tests, which were not observed in the LS group. Expression of miRNA was altered in LS and MDR groups, and we identified 4 miRNAs (miR-206, miR-374, miR-468, and miR-142-5p), which were differently modulated in the MDR group versus both control and LS groups.

Conclusion

This is the first study to identify a pharmacoresistant subgroup, resistant to 2 AEDs, in the pilocarpine-induced epilepsy model. We hypothesize that modulation of the identified miRNAs may play a key role in developing pharmacoresistance and behavioral alterations in the MDR group.