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R-loop-triggered collateral single-stranded DNA (ssDNA) nuclease activity within Class 1 Type I CRISPR-Cas systems holds immense potential for nucleic acid detection. However, the hyperactive ssDNase activity of Cas3 introduces unwanted noise and false-positive results. In this study, we identified a novel Type I-A Cas3 variant derived from Thermococcus siculi, which remains in an auto-inhibited state until it is triggered by Cascade complex and R-loop formation. This Type I-A CRISPR-Cas3 system not only exhibits an expanded protospacer adjacent motif (PAM) recognition capability but also demonstrates remarkable intolerance towards mismatched sequences. Furthermore, it exhibits dual activation modes—responding to both DNA and RNA targets. The culmination of our research efforts has led to the development of the Hyper-Active-Verification Establishment (HAVE, 惠父). This innovation enables swift and precise human papillomavirus (HPV) diagnosis in clinical samples, providing a robust molecular diagnostic tool based on the Type I-A CRISPR-Cas3 system. Our findings contribute to understanding type I-A CRISPR-Cas3 system regulation and facilitate the creation of advanced diagnostic solutions with broad clinical applicability. This study presents a novel Type I-A CRISPR-Cas3 variant for precise HPV diagnosis. It demonstrates dual activation modes and robustness without stand-alone Cas3 activity, enhancing CRISPR-Cas3 diagnostic applications. [ABSTRACT FROM AUTHOR]

Clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostics have been considered a next-generation molecular diagnosis tool. Single-readout mode has been extensively employed in massive CRISPR/Cas12a-based biosensors. In this work, we propose a one-tube dual-readout biosensor (CRISAT) for the first time for the detection of ultrasensitive nucleic acids and non-nucleic acids developed by harnessing CRISPR-ALP tandem assay. In the presence of a target, Cas12a is activated to randomly cut the single-stranded hyDNA sequence of MB@hyDNA-cALP, thus releasing abundant alkaline phosphatase (ALP) in the supernatant solution. By using 4-aminophenol phosphate as the substrate of ALP, p-aminophenol is produced, which then reacts with N-[3-(trimethoxysilyl)propyl]ethylenediamine or diethylenetriamine to generate silicon-containing polymer carbon dots (Si PCDs) or polymer carbon dots (PCDs) in situ, which can be observed by the naked eye or detected using a fluorescent device in the same solution. Using this strategy, a fluorescence and colorimetry dual-readout nanoplatform for CRISPR-based biosensors can be rationally developed. We ascertain the applicability of CRISAT by detecting the SARS-CoV-2 pseudovirus, achieving superior sensitivity and specificity. With simple modification of crRNAs, the CRISAT platform can also be employed to detect monkeypox virus (MPXV) and non-nucleic acids of adenosine triphosphate (ATP). This work shows great potential for the detection of nucleic acids and non-nucleic acids. [ABSTRACT FROM AUTHOR]

Most multiplex nucleic acids detection methods require numerous reagents and high‐priced instruments. The emerging clustered regularly interspaced short palindromic repeats (CRISPR)/Cas has been regarded as a promising point‐of‐care (POC) strategy for nucleic acids detection. However, how to achieve CRISPR/Cas multiplex biosensing remains a challenge. Here, an affordable means termed CRISPR‐RDB (CRISPR‐based reverse dot blot) for multiplex target detection in parallel, which possesses the advantages of high sensitivity and specificity, cost‐effectiveness, instrument‐free, ease to use, and visualization is reported. CRISPR‐RDB integrates the trans‐cleavage activity of CRISPR‐Cas12a with a commercial RDB technique. It utilizes different Cas12a‐crRNA complexes to separately identify multiple targets in one sample and converts targeted information into colorimetric signals on a piece of accessible nylon membrane that attaches corresponding specific‐oligonucleotide probes. It has demonstrated that the versatility of CRISPR‐RDB by constructing a four‐channel system to simultaneously detect influenza A, influenza B, respiratory syncytial virus, and SARS‐CoV‐2. With a simple modification of crRNAs, the CRISPR‐RDB can be modified to detect human papillomavirus, saving two‐thirds of the time compared to a commercial PCR‐RDB kit. Further, a user‐friendly microchip system for convenient use, as well as a smartphone app for signal interpretation, is engineered. CRISPR‐RDB represents a desirable option for multiplexed biosensing and on‐site diagnosis. [ABSTRACT FROM AUTHOR]

Cyclic GMP‐AMP synthase (cGAS)–stimulator of interferon genes (STING) signaling pathway has emerged as a key DNA‐sensing machinery in innate immunity. Activation of cGAS–STING signaling pathway mediates the production of interferons and proinflammatory cytokines. Although cGAS–STING signaling pathway shows critical function in the maintenance of gut homeostasis, overactive cGAS–STING signaling pathway leads to gastrointestinal (GI) inflammation. Harnessing the effect and mechanism of the cGAS–STING signaling pathway could be beneficial for the development of novel strategies for the treatment of GI diseases. This review presents recent advances regarding the role of cGAS–STING signaling pathway in GI inflammatory disease and cancers and describes perspective therapeutic strategies targeting the signaling pathway. [ABSTRACT FROM AUTHOR]