Wenqiang Li

We demonstrate that short single-stranded DNA generated by Pyrococcus furiosus Argonaute (PfAgo) can initiate a second round of cleavage. Based on this principle, we established a molecular diagnostic method, termed PfAgo-mediated Nucleic acid Detection (PAND). This method could detect DNA at attomolar sensitivities, distinguish single-nucleotide mutants and accomplish multiplexed detection.

Schizophrenia and major depression disorders, both being of pathological synaptogenesis, are the most common psychiatric disorders worldwide. These diseases, if not treated effectively, may cause suicide and are a serious social and economic challenge. Although schizophrenia and depression can be significantly improved with the second-generation atypical antipsychotics, rising drug resistance has limited their efficacy. Repetitive Transcranial Magnetic Stimulation (rTMS) has appeared to be a promising therapy against severe mental disorders, but it is still controversial primarily due to inadequate evaluation. It is essential to have a reliable biological marker to evaluate and diagnose schizophrenia or depression. Brain-derived neurotrophic factor (BDNF) has appeared to play a critical role in certain neurobiological modifications that may otherwise lead to schizophrenia or depression. Meta-analyses have demonstrated that serum BDNF levels were tightly correlated with the courses of severe schizophrenia and major depression disorders. This article presents a review of BDNF as a neurobiological marker for schizophrenia and depression and for the efficacy of rTMS treatments of these mental diseases.

Argonaute (Ago) proteins are conserved nucleic acid-guided proteins present in all domains of life. Eukaryotic Argonaute proteins (eAgos) are key players in RNA interference pathways and function as RNA-guided RNA endonucleases at physiological temperatures. Although eAgos are considered to evolve from prokaryotic Argonaute proteins (pAgos), previously studied pAgos were unable to catalyze RNA-guided RNA cleavage at physiological temperatures. Here, we describe a distinctive pAgo from mesophilic bacteria Kurthia massiliensis (KmAgo). KmAgo utilizes DNA guides to cleave single-stranded DNA (ssDNA) and RNA targets with high activity. KmAgo also utilizes RNA guides to cleave ssDNA and RNA targets at moderate temperatures. We show that KmAgo can use 5' phosphorylated DNA guides as small as 9-mers to cut ssDNA and RNA, like Clostridium butyricum Ago. Small DNA binding confers remarkable thermostability on KmAgo, and we can suppress the guide-independent plasmid processing activity of empty KmAgo by elevating the DNA guide loaded temperature. Moreover, KmAgo performs programmable cleavage of double-stranded DNA and highly structured RNA at 37°C. Therefore, KmAgo can be regarded as a DNA-guided programmable omnipotent nuclease for cleaving most types of nucleic acids efficiently. This study broadens our understanding of Ago proteins and could expand the pAgo-based DNA and RNA manipulation toolbox.