Biology subjects

Xun, G.

Publications and source records attributed to Xun, G..

4 recordsLinked to original sources

bioRxiv2023

Automated, self-resistance gene-guided, and high-throughput genome mining of bioactive natural products from Streptomyces

Natural products (NPs) produced by bacteria, fungi and plants are a major source of drug leads. Streptomyces species are particularly important in this regard as they produce numerous natural products with prominent bioactivities. Here we report a fully automated, scalable and high-throughput platform for discovery of bioactive natural products in Streptomyces (FAST-NPS). This platform comprises computational prediction and prioritization of target biosynthetic gene clusters (BGCs) guided by self-resistance genes, highly efficient and automated direct cloning and heterologous expression of BGCs, followed by high-throughput fermentation and product extraction from Streptomyces strains. As a proof of concept, we applied this platform to clone 105 BGCs ranging from 10 to 100 kb that contain potential self-resistance genes from 11 Streptomyces strains with a success rate of 95%. Heterologous expression of all successfully cloned BGCs in Streptomyces lividans TK24 led to the discovery of 23 natural products from 12 BGCs. We selected 5 of these 12 BGCs for further characterization and found each of them could produce at least one natural product with antibacterial and/or anti-tumor activity, which resulted in a total of 8 bioactive natural products. Overall, this work would greatly accelerate the discovery of bioactive natural products for biomedical and biotechnological applications. Graphic Abstracts O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=184 SRC="FIGDIR/small/564101v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@11068c9org.highwire.dtl.DTLVardef@4f68c5org.highwire.dtl.DTLVardef@16767edorg.highwire.dtl.DTLVardef@1d82eab_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2023

CRISPR-COPIES: An in silico platform for discovery of neutral integration sites for CRISPR/Cas-facilitated gene integration

The CRISPR/Cas system has emerged as a powerful tool for genome editing in metabolic engineering and human gene therapy. However, locating the optimal site on the chromosome to integrate heterologous genes using the CRISPR/Cas system remains an open question. Selecting a suitable site for gene integration involves considering multiple complex criteria, including factors related to CRISPR/Cas-mediated integration, genetic stability, and gene expression. Consequently, identifying such sites on specific or different chromosomal locations typically requires extensive characterization efforts. To address these challenges, we have developed CRISPR-COPIES, a COmputational Pipeline for the Identification of CRISPR/Cas-facilitated intEgration Sites. This tool leverages ScaNN, a state-of-the-art model on the embedding-based nearest neighbor search for fast and accurate off-target search and can identify genome-wide intergenic sites for most bacterial and fungal genomes within minutes. As a proof of concept, we utilized CRISPR-COPIES to characterize neutral integration sites in three diverse species: Saccharomyces cerevisiae, Cupriavidus necator, and a human cell line. In addition, we developed a user-friendly web interface for CRISPR-COPIES (https://biofoundry.web.illinois.edu/copies/). We anticipate that CRISPR-COPIES will serve as a valuable tool for targeted DNA integration and aid in the characterization of synthetic biology toolkits, enable rapid strain construction to produce valuable biochemicals and support human gene and cell therapy applications. Graphical abstractOverview and application of CRISPR-COPIES in the field of biotechnology. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/556564v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@c723a1org.highwire.dtl.DTLVardef@1f42594org.highwire.dtl.DTLVardef@1cf4bd6org.highwire.dtl.DTLVardef@7c1028_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2019

The stepwise endonuclease activity of a thermophilic Argonaute protein

Thermophilic Argonaute proteins (Agos) can function as endonucleases via specific guide-target base-pairing cleavage for host defense. The ability to cleave target DNA sequences at any arbitrary sites endows them with reprogramed DNA capacity. Here, we identify that an Ago from the hyperthermophilic archaeon Pyrococcus furiosus (PfAgo) shows a stepwise endonuclease activity, which is demonstrated by the double strand DNA cleavage directed by a single guide DNA rather than canonical one pair of guide DNAs. We reveal that the cleavage products with 5-phosphorylated ends can used as the renewed guide which is capable to induce next round of cleavage to complementary sequences of target DNA. By combining the PfAgo stepwise endonuclease activity followed by target DNA amplification, we establish a rapid and specific platform for the unambiguously multiplex gene detection, termed RADAR (Renewed-gDNA Assisted DNA-cleavage by Argonaute). In the end, RADAR was applied to distinguish of human papillomavirus of serotypes in patient samples in a single reaction, suggesting that our technique would be adopted for diagnosing application.

bioengineering↗

bioRxiv2019

A-Star, an Argonaute-directed System for Rare SNV Enrichment and Detection

The ability to detect rare mutations has revolutionized diagnosis and monitoring of tumors, but is limited by the shortage of sensitive, cost-effective and high coverage methods for identification of extremely low abundant mutations. Here, we establish a single-tube multiplex PCR system by employing thermophilic Argonaute-derived DNA-guided nuclease for highly efficient rare mutation detection, referred to as A-Star (Argonaute-directed specific target enrichment and detection), that combines the selective cleavage of the wild type DNA in the DNA denaturation step and the followed amplification of mutant DNA during PCR. A-Star enables easy detection and quantitation of rare mutations originally as low as 0.01% in allele frequency with a [>=] 5500-fold efficiency. We also demonstrate the feasibility of A-Star for detecting oncogenic mutations in complex biological systems such as solid tumors tissues and blood samples. Remarkably, A-Star could achieve the detection of multiple oncogenic genes simultaneously through a simple single-tube reaction. Taken together, our work illustrates a supersensitive and rapid nucleic acid detection system, thereby extending the utility for both research and therapeutic applications.

bioengineering↗