Biology subjects

Gu, Q.

Publications and source records attributed to Gu, Q..

63 records · Page 4Linked to original sources

bioRxiv2020

The therapeutic effects of intratumoral injection of IL12IL2GMCSF fusion protein on canine tumors

Regulating the immune system through tumor immunotherapy to defeat tumors is currently one of the most popular methods of tumor treatment. We previously found that the combinations of IL12, IL2 and GMCSF has superior antitumor activities. In this study, IL12IL2GMCSF fusion protein was produced from 293 cells transduced by expression lentiviral vector. IL12IL2GMCSF fusion protein was injected into canine tumors, and the efficacy was monitored to evaluate the potential of tumor immunotherapy. In 14 canines injected with IL12IL2GMCSF protein, 6 had a complete response (CR), 7 had a partial response (PR), and 1 had stable disease (SD). IL12IL2GMCSF fusion protein has great anti-tumor potential. Intratumoral injection of IL12IL2GMCSF can effectively treat tumors without severe adverse effects. It provides a promising immune therapeutics in canine cancers.

cancer biology↗

bioRxiv2020

SARS-CoV-2 detection with CRISPR diagnostics

The novel coronavirus (CoV) disease termed COVID-19 (Coronavirus Disease-19) caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) is causing a massive pandemic worldwide, threatening public health systems across the globe. During this ongoing COVID-19 outbreak, nucleic acid detection has played an important role in early diagnosis. Here we report a SARS-CoV-2 detection protocol using a CRISPR-based CRISPR diagnostic platform - CDetection (Cas12b-mediated DNA detection). By combining sample treatment protocols and nucleic acid amplification methods with CDetection, we have established an integrated viral nucleic acid detection platform - CASdetec (CRISPR-assisted detection). The detection limit of CASdetec for SARS-CoV-2 pseudovirus is 1 x 104 copies/mL, with no cross reactivity observed. Our assay design and optimization process can provide guidance for future CRISPR-based nucleic acid detection assay development and optimization.

molecular biology↗

bioRxiv2019

A cucumber green mottle mosaic virus vector for virus-induced gene silencing in cucurbit plants

Cucurbits produce fruits or vegetables that have great dietary importance and economic significance worldwide. The published genomes of at least 11 cucurbit species are boosting gene mining and novel breeding strategies, however genetic transformation in cucurbits is impractical as a tool for gene function validation due to low transformation efficiencies. Virus-induced gene silencing (VIGS) is a potential alternative tool. So far, very few ideal VIGS vectors are available for cucurbits. Here, we describe a new VIGS vector derived from cucumber green mottle mosaic virus (CGMMV), a monopartite virus that infects cucurbits naturally. We show that the CGMMV vector is competent to induce efficient silencing of the phytoene desaturase (PDS) gene in the model plant Nicotiana benthamiana and in cucurbits, including watermelon, melon, cucumber and bottle gourd. Infection with the CGMMV vector harboring PDS sequences of 69-300 bp in length in the form of sense-oriented or hairpin cDNAs resulted in photobleaching phenotypes in N. benthamiana and cucurbits by PDS silencing. Additional results reflect that silencing of the PDS gene could persist for over two months and the silencing effect of CGMMV-based vectors could be passaged. These results demonstrate that CGMMV vector could serve as a powerful and easy-to-use tool for characterizing gene function in cucurbits. One sentence summaryA CGMMV-based vector enables gene function studies in cucurbits, an extremely low efficiency species for genetic transformation.

pathology↗

bioRxiv2019

Upstream translation initiation expands the coding capacity of segmented negative-strand RNA viruses

Segmented negative-strand RNA viruses (sNSVs) include the influenza viruses, the bunyaviruses, and other major pathogens of humans, other animals and plants. The genomes of these viruses are extremely short. In response to this severe genetic constraint, sNSVs use a variety of strategies to maximise their coding potential. Because the eukaryotic hosts parasitized by sNSVs can regulate gene expression through low levels of translation initiation upstream of their canonical open reading frames (ORFs), we asked whether sNSVs could use upstream translation initiation to expand their own genetic repertoires. Consistent with this hypothesis, we showed that influenza A viruses (IAVs) and bunyaviruses were capable of upstream translation initiation. Using a combination of reporter assays and viral infections, we found that upstream translation in IAVs can initiate in two unusual ways: through non-AUG initiation in virally encoded untranslated regions, and through the appropriation of an AUG-containing leader sequence from host mRNAs through viral cap-snatching, a process we termed start-snatching. Finally, while upstream translation of cellular genes is mainly regulatory, for sNSVs it also has the potential to create novel viral gene products. If in frame with a viral ORF, this creates N-extensions of canonical viral proteins. If not, it allows the expression of cryptic overlapping ORFs, which we found were highly conserved in IAV and widely distributed in peribunyaviruses. Thus, by exploiting their hosts capacity for upstream translation initiation, sNSVs can expand still further the coding potential of their extremely compact RNA genomes.

molecular biology↗

bioRxiv2019

Asymmetrical cleavages of Sleeping Beauty transposons generate multiple excised transposon fragments during transposition

Although the Sleeping Beauty (SB) transposon is the most validated DNA transposon used as a gene delivery vehicle in vertebrates, many details of the excision and integration steps in the transposition process are unclear. We have probed in detail the products of the excision step and apparent selective integration of a subset of those products during transposition. The standard model of SB transposase-mediated transposition includes symmetrical cleavages at both ends of the transposon for excision and re-integration in another DNA sequence. In our analysis of excised transposon fragments (ETFs), we found evidence for the requirement of certain flanking sequences for efficient cleavage and a significant rate of asymmetrical cleavage during the excision process that generates multiple ETFs. Our results suggest that the cleavage step by SB transposase is not as precise as indicated in most models. Repair of the donor ends can produce eight footprint sequences (TACTGTA, TACAGTA, TACATA, TACGTA, TATGTA, TACTA, TAGTA and TATA). Our data also suggest that mismatch repair (MMR) is not an essential requirement for footprint formation. Among the twenty liberated ETFs, only eight appear to effectively re-integrate into TA sites distributed across the genome, supporting earlier findings of unequal rates of excision and reintegration during SB transposition. These findings may be important in considerations of efficiency of SB transposon remobilization, selection of TA integration sites and detection of SB excision and integration loci, all of which may be important in human gene therapy.

molecular biology↗

bioRxiv2018

Study on the Difference of Prokaryotic Flora Structure on the Surface of Micro-nano Coating with Different Antifouling Property

Low surface energy composite antifouling coatings prepared from carbon nanotubes (CNTs) and polydimethylsiloxane (PDMS) have good values for investigation of biofouling-related biological questions on marine biofilm. In order to deeply study the mechanism of antifouling on the surface of CNTs-PDMS coatings, it is necessary to investigate the structure of the microbial flora in the early biofilm on the coating surface. In the present study, the specific aim of this study was to investigate the structure differences of prokaryotic flora in biofilm samples at the early stage of biofouling through 16S rDNA based high-throughput DNA sequencing. By annotating high-throughput DNA sequencing results, this study identified dominant prokaryotic phyla and genera in biofilms of CNTs-PDMS coatings and identified significant differences in microbial composition and its dynamics among different coatings. Though the analysis of the Shannon index, Simpson index, Chao1 index and ACE index, coatings with better antifouling properties and antifouling properties have significant differences in community diversity and abundance, indicating different antifouling properties can affect the type and content of biofilm communities. According to the canonical correspondence analysis (CCA), time and temperature are more related to microbial community distribution, while the diameter and length of nanomaterials are less correlated. Through this study, the differences in microbial composition and content of prokaryotic communities, differences in diversity and abundance of sample communities, the differences between multiple samples and the correlation with important environmental factors were preliminarily analyzed, which laid a decent foundation for further research on the mechanism of anti-fouling on the surface of CNTs and PDMS coatings.

molecular biology↗

bioRxiv2018

Continuous-trait probabilistic model for comparing multi-species functional genomic data

A large amount of multi-species functional genomic data from high-throughput assays are becoming available to help understand the molecular mechanisms for phenotypic diversity across species. However, continuous-trait probabilistic models, which are key to such comparative analysis, remain underexplored. Here we develop a new model, called phylogenetic hidden Markov Gaussian processes (Phylo-HMGP), to simultaneously infer heterogeneous evolutionary states of functional genomic features in a genome-wide manner. Both simulation studies and real data application demonstrate the effectiveness of Phylo-HMGP. Importantly, we applied Phylo-HMGP to analyze a new cross-species DNA replication timing (RT) dataset from the same cell type in five primate species (human, chimpanzee, orangutan, gibbon, and green monkey). We demonstrate that our Phylo-HMGP model enables discovery of genomic regions with distinct evolutionary patterns of RT. Our method provides a generic framework for comparative analysis of multi-species continuous functional genomic signals to help reveal regions with conserved or lineage-specific regulatory roles.

bioinformatics↗

bioRxiv2017

Inhibition of mitochondrial fission preserves photoreceptors after retinal detachment

Photoreceptor degeneration is a leading cause of visual impairment worldwide. Separation of neurosensory retina from the underlying retinal pigment epithelium is a prominent feature preceding photoreceptor degeneration in a variety of retinal diseases. Although ophthalmic surgeries have been well developed to restore retinal structures, post-op patients usually experience progressive photoreceptor degeneration and irreversible vision loss that is incurable at present. Previous studies point to a critical role of mitochondria-mediated apoptotic pathway in photoreceptor degeneration, but the upstream triggers remain largely unexplored. In this study, we show that after experimental RD induction, photoreceptors activate dynamin-related protein 1 (Drp1)-dependent mitochondrial fission pathway and subsequent apoptotic cascades. Mechanistically, endogenous ROS is necessary for Drp1 activation in vivo and exogenous ROS insult is sufficient to activate Drp1-dependent mitochondrial fission in cultured photoreceptors. Accordingly, inhibition of Drp1 activity effectively preserves mitochondrial integrity and rescues photoreceptors. Collectively, our data delineates a ROS-Drp1-mitochondria axis that promotes photoreceptor degeneration in retinal diseased models.

neuroscience↗

bioRxiv2017

Genotyping Of Zebrafish Embryos Fixed By Paraformaldehyde

The rapid generation of various species and strains of zebrafish using CRISPR/Cas9 technology has dramatically accelerated the interrogation of gene function in vivo. So far, several approaches for genotyping of unfixed genome-modified animals have been successfully developed, such as Surveyor assays, T7 endonuclease 1 (T7E1) assays, High Resolution Melt Analysis (HRMA) and PAGE-based genotyping approach. However, there is few published genotyping protocol for the embryos of lethal zebrafish mutants fixed by paraformaldehyde. We have designed this genotyping protocol so that it can be performed in a single step with reliable results. The protocol covers all steps to obtain the genotypes.

molecular biology↗