Molecular and crystal structures of dialkylated adenines (N6,N9-Me2Ade, N3,N6-MeBnAde) and cytosines (N1,N4-Me2Cyt)

Identification and quantification of N6-methyladenosine by chemical derivatization coupled with 19F NMR spectroscopy

N 6-Methyladenosine (6mA) is a well-known prokaryotic DNA modification that has been shown to play epigenetic roles in eukaryotic DNA. Accurate detection and quantification of 6mA are prerequisites for molecular understanding of the impact of 6mA modification on DNA. However, the existing methods have several problems, such as high false-positive rate, time-consuming and complex operating procedures. Chemical sensors for the selective detection of 6mA modification are rarely reported in the literature. Fluorinated phenylboronic acid combined with 19F NMR analysis is an effective method for determining DNA or RNA modification. In this study, we presented a simple and fast chemical method for labelling the 6th imino group of 6mA using a boric-acid-derived probe. Besides, the trifluoromethyl group of trifluoromethyl phenylboronic acid (2a) could detect 6mA modification through 19F NMR. Combined with this sensor system, 6mA modification could be detected well and quickly in 6 types of deoxynucleoside mixtures and DNA samples. Taken together, the method developed in the current study has potential for specific detection of 6mA in biological samples.

Structurally Simple, Readily Available Peptidomimetic 1-Benzyl-5-methyl-4-( n-octylamino)pyrimidin-2(1 H)-one Exhibited Efficient Cardioprotection in a Myocardial Ischemia (MI) Mouse Model

TLR4, a member of the Toll-like receptor (TLR) family, serves as a pattern recognition receptor in the innate immune response to microbial pathogens. TLR4 also regulates the inflammatory reaction to ischemic injury in the heart. The TRIF-related adaptor molecule (TRAM) is an adapter that recruits the Toll/interleukin 1 receptor (TIR) domain, which contains adapter-inducing IFN-β (TRIF), to activate TLR4, following TRIF-dependent cytokine gene transcription. On the basis of a known TRAM-derived decoy peptide, 10 of its peptidomimetics were synthesized. One of them, 1-benzyl-5-methyl-4-( n-octylamino)pyrimidin-2(1 H)-one (21), exhibited high potency and efficacy in vitro. In vitro results and in silico analysis provided evidence for the possible direct interaction of 21 with the TLR4 complex. Administered in mice, 21 was able to block the pathophysiological manifestation of MI, restoring the concomitant tissue damage, with a 100% survival rate. Thus, inhibition of TLR4-mediated inflammation in postischemic myocardium could be used as an approach for developing cardioprotective drugs.

A novel synthesis and detection method for cap-associated adenosine modifications in mouse mRNA

A method is described for the detection of certain nucleotide modifications adjacent to the 5' 7-methyl guanosine cap of mRNAs from individual genes. The method quantitatively measures the relative abundance of 2'-O-methyl and N⁶,2'-O-dimethyladenosine, two of the most common modifications. In order to identify and quantitatify the amounts of N⁶,2'-O-dimethyladenosine, a novel method for the synthesis of modified adenosine phosphoramidites was developed. This method is a one step synthesis and the product can directly be used for the production of N⁶,2'-O-dimethyladenosine containing RNA oligonucleotides. The nature of the cap-adjacent nucleotides were shown to be characteristic for mRNAs from individual genes transcribed in liver and testis.