Interactome profiling of Crimean-Congo hemorrhagic fever virus glycoproteins.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a biosafety level-4 pathogen requiring urgent research and development efforts. The glycoproteins of CCHFV, Gn and Gc, are considered to play multiple roles in the viral life cycle by interactions with host cells; however, these interactions remain largely unclear to date. Here, we analyzed the cellular interactomes of CCHFV glycoproteins and identified 45 host proteins as high-confidence Gn/Gc interactors. These host molecules are involved in multiple cellular biological processes potentially associated with the physiological actions of the viral glycoproteins. Then, we elucidated the role of a representative cellular protein, HAX1. HAX1 interacts with Gn by its C-terminus, while its N-terminal region leads to mitochondrial localization. By the strong interaction, HAX1 sequestrates Gn to mitochondria, thus depriving Gn of its normal Golgi localization that is required for functional glycoprotein-mediated progeny virion packaging. Consistently, the inhibitory activity of HAX1 against viral packaging and hence propagation was further elucidated in the contexts of pseudotyped and authentic CCHFV infections in cellular and animal models. Together, the findings provide a systematic CCHFV Gn/Gc-cell protein-protein interaction map, but also unravel a HAX1/mitochondrion-associated host antiviral mechanism, which may facilitate further studies on CCHFV biology and therapeutic approaches.

A Novel Software and Method for the Efficient Development of Polymorphic SSR Loci Based on Transcriptome Data.

Traditional methods for developing polymorphic microsatellite loci without reference sequences are time-consuming and labor-intensive, and the polymorphisms of simple sequence repeat (SSR) loci developed from expressed sequence tag (EST) databases are generally poor. To address this issue, in this study, we developed a new software (PSSRdt) and established an effective method for directly obtaining polymorphism details of SSR loci by analyzing diverse transcriptome data. The new method includes three steps, raw data processing, PSSRdt application, and loci extraction and verification. To test the practicality of the method, we successfully obtained 1940 potential polymorphic SSRs from the transcript dataset combined with 44 pea aphid transcriptomes. Fifty-two SSR loci obtained by the new method were selected for validating the polymorphic characteristics by genotyping in pea aphid individuals. The results showed that over 92% of SSR loci were polymorphic and 73.1% of loci were highly polymorphic. Our new software and method provide an innovative approach to microsatellite development based on RNA-seq data, and open a new path for the rapid mining of numerous loci with polymorphism to add to the body of research on microsatellites.

Identification and Functional Characterization of Two Sigma Glutathione S-Transferase Genes From Bird Cherry-Oat Aphid (Hemiptera: Aphididae).

The bird cherry-oat aphid, Rhopalosiphum padi (L.), is an insect pest that persistently attacks wheat crops worldwide. Glutathione S-transferases (GSTs) are important detoxification enzymes that play roles in insecticide resistance. In this study, we identified two GST genes (RpGSTS1 and RpGSTS2) from R. padi. Phylogenetic analysis indicated that the genes are associated with the sigma class of insect GSTs. The RpGSTS1 and RpGSTS2 contain nine α-helices and five ß-sheets connected by loops, and had 60 and 50% homology with the 3D structure of the Blattella germanica GST5. We tested the toxicity of chlorpyrifos, imidacloprid, isoprocarb, sulfoxaflor, and λ-cyhalothrin to R. padi, and found that the toxicity of five insecticides to the aphid varied. The detoxification activity of GSTs and the expression patterns of RpGSTS1 and RpGSTS2 after insecticide treatments were also analyzed. Compared to the control, the GST activity was increased by 23, 18.5, 13, and 11.5% in aphids treated by LC50 concentrations of chlorpyrifos, isoprocarb, imidacloprid, and sulfoxaflor, respectively. Exposure to different chemical insecticides showed different effects on the expression of RpGSTS1 and RpGSTS2. These results indicate that RpGSTS1 and RpGSTS2 have unique biochemical characteristics and may play roles in resistance to insecticides in R. padi.