N6-methyladenosine (m6A) is the most prevalent and reversible internal modification in mammalian messenger and non-coding RNAs. We report here that human METTL14 catalyzes m6A RNA methylation. Together with METTL3, the only previously known m6A methyltransferase, these two proteins form a stable heterodimer core complex of METTL3-14 that functions in cellular m6A deposition on mammalian nuclear RNAs. WTAP, a mammalian splicing factor, can interact with this complex and affect this methylation.

The formation of a highly stable inclusion complex between 2,7-dimethyldiazapyrenium (Me(2)DAP(2+)) and the cucurbit[8]uril host (CB8) was demonstrated by X-ray crystallography; MALDI-TOF mass spectrometry; and (1)H NMR, electronic absorption, and emission spectroscopy. The equilibrium association constant was determined to be 8.9(+/-0.2)x10(5) L mol(-1) from UV-visible data and 8.4(+/-1.5) x 10(5) L mol(-1) from fluorescence data. The Me(2)DAP(2+).CB8 inclusion complex acted as a host to bind compounds containing aromatic pi-donor moieties (D), such as catechol and dopamine. This point was demonstrated by (1)H NMR spectroscopy, and electrochemical and emission measurements. Fluorescence detection of the Me(2)DAP(2+).D.CB8 ternary complexes was evident in aqueous solution and on the surface of silica particles, to which fluorescent diazapyrenium units had been covalently immobilized.

Summary RNA molecules can attach to chromatin. It remains difficult to know what RNAs are associated with chromatin and where are the genomic target loci of these RNAs. Here, we present MARGI (Mapping RNA-genome interactions), a technology to massively reveal native RNA-chromatin interactions from unperturbed cells. The gist of this technology is to ligate chromatin associated RNAs (caRNAs) with their target genomic sequences by proximity ligation, forming RNA-DNA chimeric sequences, which are converted to sequencing library for paired-end sequencing. Using MARGI, we produced RNA-genome interaction maps for human embryonic stem (ES) cells and HEK cells. MARGI revealed hundreds of caRNAs including previously known XIST, SNHG1, NEAT1, MALAT1, as well as each caRNA's genomic interaction loci. Using a cross-species experiment, we estimated that approximately 2.2% of MARGI identified interactions were false positives. In ES and HEK cells, the RNA ends of more than 5% of MARGI read pairs were mapped to distal or inter-chromosomal locations as compared to the locations of their corresponding DNA ends. The majority of transcription start sites are associated with distal or inter-chromosomal caRNAs. ChIP-seq reported H3K27ac and H3K4me3 levels are positively while H3K9me3 is negatively correlated with MARGI reported RNA attachment levels. The MARGI technology should facilitate revealing novel RNA functions and their genomic target regions.

is a promising industrial microorganism as well as a major human pathogen. The recent emergence of carbapenem-resistant has posed a serious threat to public health worldwide, emphasizing a dire need for novel therapeutic means against drug-resistant Despite the critical importance of genetics in bioengineering, physiology studies, and therapeutic-means development, genome editing, in particular, the highly desirable scarless genetic manipulation in , is often time-consuming and laborious. Here, we report a two-plasmid system, pCasKP-pSGKP, used for precise and iterative genome editing in By harnessing the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 genome cleavage system and the lambda Red recombination system, pCasKP-pSGKP enabled highly efficient genome editing in using a short repair template. Moreover, we developed a cytidine base-editing system, pBECKP, for precise C→T conversion in both the chromosomal and plasmid-borne genes by engineering the fusion of the cytidine deaminase APOBEC1 and a Cas9 nickase. By using both the pCasKP-pSGKP and the pBECKP tools, the gene was confirmed to be the major factor that contributed to the carbapenem resistance of a hypermucoviscous carbapenem-resistant strain. The development of the two editing tools will significantly facilitate the genetic engineering of Genetics is a key means to study bacterial physiology. However, the highly desirable scarless genetic manipulation is often time-consuming and laborious for the major human pathogen We developed a CRISPR-Cas9-mediated genome-editing method and a cytidine base-editing system, enabling rapid, highly efficient, and iterative genome editing in both industrial and clinically isolated strains. We applied both tools in dissecting the drug resistance mechanism of a hypermucoviscous carbapenem-resistant strain, elucidating that the gene was the major factor that contributed to the carbapenem resistance of the hypermucoviscous carbapenem-resistant strain. Utilization of the two tools will dramatically accelerate a wide variety of investigations in diverse strains and relevant species, such as gene characterization, drug discovery, and metabolic engineering.

SummaryPseudomonas species are a large class of gram-negative bacteria that exhibit significant biomedical, ecological, and industrial importance. Despite the extensive research and wide applications, genetic manipulation in Pseudomonas species, in particular in the major human pathogen Pseudomonas aeruginosa, remains a laborious endeavor. Here we report the development of a genome editing method pCasPA/pACRISPR by harnessing the CRISPR/Cas9 and the phage λ-Red recombination systems. The method allows for efficient and scarless genetic manipulation in P. aeruginosa. By engineering the fusion of the cytidine deaminase APOBEC1 and the Cas9 nickase, we further develop a base editing system pnCasPA-BEC, which enables highly efficient gene inactivation and point mutations in a variety of Pseudomonas species, such as P. aeruginosa, Pseudomonas putida, Pseudomonas fluorescens, and Pseudomonas syringae. Application of the two genome editing methods will dramatically accelerate a wide variety of investigations, such as bacterial physiology study, drug target exploration, and metabolic engineering.

We use a combined, theoretical and experimental, approach to investigate the spectroscopic properties and electronic structure of three ruthenium polypyridyl complexes, [Ru(tpy)(2)](2+), [Ru(tpy)(bpy)(H(2)O)](2+), and [Ru(tpy)(bpy)(Cl)](+) (tpy = 2,2':6',2''-terpyridine and bpy = 2,2'-bipyridine) in acetone, dichloromethane, and water. All three complexes display strong absorption bands in the visible region corresponding to a metal-to-ligand-charge-transfer (MLCT) transition, as well as the emission bands arising from the lowest lying (3)MLCT state. [Ru(tpy)(bpy)(Cl)](+) undergoes substitution of the Cl(-) ligand by H(2)O in the presence of water. Density functional theory (DFT) calculations demonstrate that the triplet potential energy surfaces of these molecules are complicated, with several metal-centered ((3)MC) and (3)MLCT states very close in energy. Solvent effects are included in the calculations via the polarizable continuum model as well as explicitly, and it is shown that they are critical for proper characterization of the triplet excited states of these complexes.

Staphylococcus aureus, a major human pathogen, has been the cause of serious infectious diseases with a high mortality rate. Although genetics is a key means to study S. aureus physiology, such as drug resistance and pathogenesis, genetic manipulation in S. aureus is always time-consuming and labor-intensive. Here we report a CRISPR/Cas9 system (pCasSA) for rapid and efficient genome editing, including gene deletion, insertion, and single-base substitution mutation in S. aureus. The designed pCasSA system is amenable to the assembly of spacers and repair arms by Golden Gate assembly and Gibson assembly, respectively, enabling rapid construction of the plasmids for editing. We further engineered the pCasSA system to be an efficient transcription inhibition system for gene knockdown and possible genome-wide screening. The development of the CRISPR/Cas9-mediated genome editing and transcription inhibition tools will dramatically accelerate drug-target exploration and drug development.

The only operating mechanism in the oxidation of water to dioxygen catalyzed by the mononuclear cis-[RuII(bpy)2(H2O)2]2+ complex when treated with excess CeIV was unambiguously established. Theoretical calculations together with 18O-labeling experiments (see plot) revealed that it is the nucleophilic attack of water on a Ru=O group