A comparison of the large-scale gene expression patterns in summer and fall migratory Pantala flavescens (Fabricius) in northern China.

Pantala flavescens (Fabricius) is the most well-known seasonal migratory insect. This research focused on the molecular response of P. flavescens migration in summer and fall. A total of 17,810 assembled unigenes were obtained and 624 differentially expressed genes (DEGs) were identified in summer migration compared to fall migration. A number of DEGs, including cpr49Ae, itm2b, chitinase, cpr11B, laccase2, nd5, vtg2 and so on, had previously been reported to be involved in cold- and high-temperature resistance. Functional enrichment analysis showed three pathways 'that antibacterial humoral response, response to bacterial, and lipid transporter activity' were significantly enriched in summer migration while that six pathways 'structural constituent of cuticle, chitin binding, mitochondrion, propanoate metabolism, citrate cycle, hypertrophic cardiomyopathy' were significantly enriched in fall migration. These results will provide a valuable baseline for further understanding of the molecular mechanisms of insect adaptation to different climate migrations.

Genetic Diversity and Demographic History of Globe Skimmers (Odonata: Libellulidae) in China Based on Microsatellite and Mitochondrial DNA Markers.

To analyze genetic characters of migratory dragonflies, we used 10 microsatellite markers and a partial sequence of the mitochondrial gene Cytb to investigate genetic diversity and demographic history among 19 populations of P. flavescens in eastern the monsoon region of China. In a Bayesian clustering analysis of the microsatellite data, three distinct clades were present, and each population consisted of a mixture of individuals from the three clusters. An AMOVA of the data from both the microsatellite loci and Cytb revealed that genetic variation was mainly within each population. For the 543 individuals from the 19 regions, 77 unique haplotypes were obtained by DnaSP 4.0, and a median-joining network showed no obvious geographical pattern and displayed high gene flow and minimal population genetic structure among the 19 populations. According to a Mantel test, there was no significant association between genetic distance and geographic distribution and no isolation by distance. Mismatch distribution and neutrality tests showed no demographic expansion for the 19 populations. Microsatellite and mitochondrial DNA data suggested there was high gene flow and low differentiation among the populations. These results will help provide valuable information to study the migratory route of insects, especially important agricultural pests.

TARBP2 inhibits IRF7 activation by suppressing TRAF6-mediated K63-linked ubiquitination of IRF7.

Interferon regulatory factor 7 (IRF7), a crucial regulator of type I interferons (IFNs), plays a crucial role in resistance to viral infection. The abnormal production of type I IFNs is associated with many types of disease, such as cancer and inflammatory disorders. Thus, understanding the post-translational modifications of IRF7 is essential to promoting an appropriate immune response. We have recently showed that the TAR RNA binding protein 2 (TARBP2) suppresses IFN-ß production and the innate antiviral response by targeting MAVS. Here, we further identified TARBP2 as a novel inhibitor of IRF7, which inhibits IRF7-mediated IFN-ß production triggered by the Sendai virus in 293 T cells. Overexpression of TARBP2 inhibits the phosphorylation as well as the K63-linked ubiquitination of IRF7, whilst TARBP2 also impairs the stability of endogenous TRAF6. Furthermore, TARBP2 participates in the interaction between IRF7 and TRAF6, thereby suppressing TRAF6-mediated K63-linked ubiquitination of IRF7, which is a prerequisite of IRF7 phosphorylation. Our findings further reveal the mechanism by which TARBP2 regulates the antiviral signaling pathways of the innate immune system.

THO Complex Subunit 7 Homolog Negatively Regulates Cellular Antiviral Response against RNA Viruses by Targeting TBK1.

RNA virus invasion induces a cytosolic RIG-I-like receptor (RLR) signaling pathway by promoting assembly of the Mitochondrial antiviral-signaling protein (MAVS) signalosome and triggers the rapid production of type I interferons (IFNs) and proinflammatory cytokines. During this process, the pivotal kinase TANK binding kinase 1 (TBK1) is recruited to the MAVS signalosome to transduce a robust innate antiviral immune response by phosphorylating transcription factors interferon regulatory factor 3 (IRF3) and nuclear factor (NF)-κB and promoting their nuclear translocation. However, the molecular mechanisms underlying the negative regulation of TBK1 are largely unknown. In the present study, we found that THO complex subunit 7 homolog (THOC7) negatively regulated the cellular antiviral response by promoting the proteasomal degradation of TBK1. THOC7 overexpression potently inhibited Sendai virus- or polyI:C-induced IRF3 dimerization and phosphorylation and IFN-ß production. In contrast, THOC7 knockdown had the opposite effects. Moreover, we simulated a node-activated pathway to show that THOC7 regulated the RIG-I-like receptors (RLR)-/MAVS-dependent signaling cascade at the TBK1 level. Furthermore, THOC7 was involved in the MAVS signalosome and promoted TBK1 degradation by increasing its K48 ubiquitin-associated polyubiquitination. Together, these findings suggest that THOC7 negatively regulates type I IFN production by promoting TBK1 proteasomal degradation, thus improving our understanding of innate antiviral immune responses.

The complete mitochondrial genome sequence of Acisoma panorpoides Rambur, 1842 (Odonate: Libellulidae).

The phylogenetic relationships of dragonflies have received great attention all the time. For a better understanding the phylogenies among odonate insects, the paper presented the complete mitochondrial genome of Acisoma panorpoides based on next generation sequencing data of total genomic DNA. The total length comprised 15,249 bp and the 37 genes (2 rRNA genes, 13 protein coding genes and 22 tRNA genes). Gene content and gene arrangement were identical to other odonate mitogenomes. Phylogenetic analyses using the whole sequences of the mitochondrial genome placed A. panorpoides as a sister species to Hydrobasileus croceus in Libellulidae.

RACK1 attenuates RLR antiviral signaling by targeting VISA-TRAF complexes.

Virus-induced signaling adaptor (VISA), which mediates the production of type I interferon, is crucial for the retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) signaling pathway. Upon viral infection, RIG-I recognizes double-stranded viral RNA and interacts with VISA to mediate antiviral innate immunity. However, the mechanisms underlying RIG/VISA-mediated antiviral regulation remain unclear. In this study, we confirmed that receptor for activated C kinase 1 (RACK1) interacts with VISA and attenuates the RIG/VISA-mediated antiviral innate immune signaling pathway. Overexpression of RACK1 inhibited the interferon-ß (IFN-ß) promoter; interferon-stimulated response element (ISRE); nuclear factor kappa B (NF-κB) activation; and dimerization of interferon regulatory factor 3 (IRF3) mediated by RIG-I, VISA, and TANK-binding kinase 1 (TBK1). A reduction in RACK1 expression level upon small interfering RNA knockdown increased RIG/VISA-mediated antiviral transduction. Additionally, RACK1 disrupted formation of the VISA-tumor necrosis factor receptor-associated factor 2 (TRAF2), VISA-TRAF3, and VISA-TRAF6 complexes during RIG-I/VISA-mediated signal transduction. Additionally, RACK1 enhanced K48-linked ubiquitination of VISA, attenuated its K63-linked ubiquitination, and decreased VISA-mediated antiviral signal transduction. Together, these results indicate that RACK1 interacts with VISA to repress downstream signaling and downregulates virus-induced IFN-ß production in the RIG-I/VISA signaling pathway.

FKBP8 inhibits virus-induced RLR-VISA signaling.

The mitochondrial antiviral signal protein mitochondrial antiviral signaling protein, also known as virus-induced signaling adaptor (VISA), plays a key role in regulating host innate immune signaling pathways. This study identifies FK506 binding protein 8 (FKBP8) as a candidate interacting protein of VISA through the yeast two-hybrid technique. The interaction of FKBP8 with VISA, retinoic acid inducible protein 1 (RIG-I), and IFN regulatory factor 3 (IRF3) was confirmed during viral infection in mammalian cells by coimmunoprecipitation. Overexpression of FKBP8 using a eukaryotic expression plasmid significantly attenuated Sendai virus-induced activation of the promoter interferons ß (IFN-ß), and transcription factors nuclear factor κ-light chain enhancer of activated B cells (NF-κB) and IFN-stimulated response element (ISRE). Overexpression of FKBP8 also decreased dimer-IRF3 activity, but enhanced virus replication. Conversely, knockdown of FKBP8 expression by RNA interference showed opposite effects. Further studies indicated that FKBP8 acts as a negative interacting partner to regulate RLR-VISA signaling by acting on VISA and TANK binding kinase 1 (TBK1). Additionally, FKBP8 played a negative role on virus-induced signaling by inhibiting the formation of TBK1-IRF3 and VISA-TRAF3 complexes. Notably, FKBP8 also promoted the degradation of TBK1, RIG-I, and TRAF3 resulting from FKBP8 reinforced Sendai virus-induced endogenous polyubiquitination of RIG-I, TBK1, and TNF receptor-associated factor 3 (TRAF3). Therefore, a novel function of FKBP8 in innate immunity antiviral signaling regulation was revealed in this study.

TARBP2 negatively regulates IFN-ß production and innate antiviral response by targeting MAVS.

MAVS as an essential receptor protein for anti-virus innate immunity plays an important role in the production of virus-induced typeⅠ interferon and regulation of interferon regulatory factor 3/7. Understanding the MAVS-mediated antiviral signaling pathway can provide detailed insights. In this study, we identify transactivation response element RNA-binding protein (TARBP2), as an inhibitor of the cellular protein kinase PKR, negatively regulates virus -induced IFN-ß production by targets MAVS. Overexpression of TARBP2 inhibits virus-induced IFN-ß production as well as cellular antiviral response. Then knockdown of TARBP2 inhibited virus-induced IFN-ß signaling. Further studies demonstrated that TARBP2 interacted with MAVS and targeted MAVS to abrogate MAVS-RIG-I and MAVS-TRAF3 association. Our findings suggest that TARBP2 is an important non-redundant virus-mediated negative regulator of typeⅠ interferon.

Seasonal Migration of Pantala flavescens Across the Bohai Strait in Northern China.

Pantala flavescens (Fabricius 1798) (Odonata: Libellulidae) is one of the most common species of migratory dragonflies. P. flavescens adults were captured by a searchlight trap on Beihuang Island (BH Island; 38°24'N, 120°55'E) from 2003 to 2016, where there is no freshwater. This inspired our research to analyze the pattern of seasonal migration and population dynamics. Stable hydrogen isotope measurement and the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) were used to simulate the migration pathway of P. flavescens between different breeding habitats. The results showed that there was no significant difference among population numbers of this overseas migration across years (F13, 2161 = 0.85, P = 0.604); however, the numbers were significantly different across months (F5, 2161 = 3.91, P = 0.003). Our geospatial natal assignment model suggested that P. flavescens trapped on BH were originated in different geographical regions and might have three movement strategies: wandering around northern China and north-bound (positive) and south-bound (negative) movements. Among them, the majority were engaged in wandering around northern China. Model simulations suggested that P. flavescens toured around BH. The results contribute to the knowledge of P. flavescens population ecology in a large-scale geographic region and will aid in the prediction and interpretation of insect migration patterns in response to climate change.

Complete mitochondrial genome of the Trichogaster trichopterus (Anabantoidei: Osphronemidae).

The complete mitochondrial genome of Trichogaster trichopterus was determined in this study. It is 16,452 bp in size and consists of 2 rRNA genes, 13 protein-coding genes, 22 tRNA genes and 1 non-coding control regions (D-loop). The overall base composition of the heavy strand of the T. trichopterus mitochondrial genome is A: 29.50%, T: 28.36%, C: 26.62% and G: 15.49%. The total length of the 13 protein-coding genes was 11,427 bp. Analysis of the genes indicated the high genetic variability among Osphronemidae species.

Development of 10 microsatellite markers from Pantala flavescens and their applicability in studying genetics diversity.

Pantala flavescens (Fabricius 1798) is one of the most common species among migration dragonflies. It is often encountered in large swarms during migration or directed dispersal flights. For a better understanding of its gene flow, genetic structure and migration patterns throughout the world, 10 polymorphic microsatellite markers were isolated in this study. We respectively collected 32 P. flavescens from three places (Hunan, Liaoning and Heilongjiang) and 20 P. flavescens from Beijing. Partial genomic libraries containing microsatellite sequences were constructed with magnetic-bead enrichment method. By screening, sequence analysis, PCR amplification and so on, ten 10 polymorphic microsatellite markers were isolated. In order to assess their applicability, genetic diversity of these novel markers was tested in 96 individuals from three populations in China (Hunan, Liaoning and Heilongjiang). These markers were highly polymorphic, with 3-12 alleles per markers. The observed (Ho) and expected (He) heterozygosities ranged 0.321-0.667 and from 0.531 to 0.948 respectively. The genetic difference between Hunan and Liaoning is 0.429, while the genetic difference between Liaoning and Heilongjiang is 0.0508. These microsatellite markers for P. flavescens were developed for the first time, and will be a powerful tool for studying population genetic diversity and dispersal behavior of P. flavescens in China and worldwide.

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 August 2009-30 September 2009.

This article documents the addition of 238 microsatellite marker loci and 72 pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Adelges tsugae, Artemisia tridentata, Astroides calycularis, Azorella selago, Botryllus schlosseri, Botrylloides violaceus, Cardiocrinum cordatum var. glehnii, Campylopterus curvipennis, Colocasia esculenta, Cynomys ludovicianus, Cynomys leucurus, Cynomys gunnisoni, Epinephelus coioides, Eunicella singularis, Gammarus pulex, Homoeosoma nebulella, Hyla squirella, Lateolabrax japonicus, Mastomys erythroleucus, Pararge aegeria, Pardosa sierra, Phoenicopterus ruber ruber and Silene latifolia. These loci were cross-tested on the following species: Adelges abietis, Adelges cooleyi, Adelges piceae, Pineus pini, Pineus strobi, Tubastrea micrantha, three other Tubastrea species, Botrylloides fuscus, Botrylloides simodensis, Campylopterus hemileucurus, Campylopterus rufus, Campylopterus largipennis, Campylopterus villaviscensio, Phaethornis longuemareus, Florisuga mellivora, Lampornis amethystinus, Amazilia cyanocephala, Archilochus colubris, Epinephelus lanceolatus, Epinephelus fuscoguttatus, Symbiodinium temperate-A clade, Gammarus fossarum, Gammarus roeselii, Dikerogammarus villosus and Limnomysis benedeni. This article also documents the addition of 72 sequencing primer pairs and 52 allele specific primers for Neophocaena phocaenoides.