The FTO protein is unequivocally reported to play a critical role in human obesity and in the regulation of cellular levels of m(6)A modification, which makes FTO a significant and worthy subject of study. Here, we identified that fluorescein derivatives can selectively inhibit FTO demethylation, and the mechanisms behind these activities were elucidated after we determined the X-ray crystal structures of FTO/fluorescein and FTO/5-aminofluorescein. Furthermore, these inhibitors can also be applied to the direct labeling and enrichment of FTO protein combined with photoaffinity labeling assay.
Powerful information processing and ubiquitous computing are crucial for all machines and living organisms. The Watson-Crick base-pairing principle endows DNA with excellent recognition and assembly abilities, which facilitates the design of DNA computers for achieving intelligent systems. However, current DNA computational systems are always constrained by poor integration efficiency, complicated device structures or limited computational functions. Here, we show a DNA arithmetic logic unit (ALU) consisting of elemental DNA logic gates using polymerase-mediated strand displacement. The use of an enzyme resulted in highly efficient logic gates suitable for multiple and cascaded computation. Based on our basic single-rail DNA configuration, additional combined logic gates (e.g., a full adder and a 4:1 multiplexer) have been constructed. Finally, we integrate the gates and assemble the crucial ALU. Our strategy provides a facile strategy for assembling a large-scale complex DNA computer system, highlighting the great potential for programming the molecular behaviors of complicated biosystems.
G-Quadruplex (G4) is a noncanonical nucleic acid secondary structure with multiple biofunctions. Identifying G4-related proteins (G4RPs) is important for understanding the roles of G4 in biology. Current methods to identify G4RPs include discovery from specific biological processes or in vitro pull-down assays with specific G4 sequences. Here, we report an in vivo strategy used to identify G4RPs with extensive sequence tolerance based on G4 ligand-mediated cross-linking. Applying this method, we identified 114 and 281 G4RPs in SV589 and MM231 cells, respectively. The results successfully overlapped with all the pull-down assay literature. Through the electrophoretic mobility shift assay (EMSA), we identified some new G4binding proteins. Moreover, enhanced cross-linking and immunoprecipitation (eCLIP) confirmed that one newly identified G4-binding protein, SERBP1, interacts with G4 in the cellular environment. The method we developed provides a new strategy for identifying proteins that interact with nucleic secondary structures in cells and benefit the study of their biological roles.
Innovative detection techniques to achieve precise m6A distribution within mammalian transcriptome can advance our understanding of its biological functions. We specifically introduced the atom-specific replacement of oxygen with progressively larger atoms (sulfur and selenium) at 4-position of deoxythymidine triphosphate to weaken its ability to base pair with m6A, while maintaining A-T* base pair virtually the same as the natural one. 4SedTTP turned out to be an outstanding candidate that endowed m6A with a specific signature of RT truncation, thereby making this "RT-silent" modification detectable with the assistance of m6A demethylase FTO through next-generation sequencing. This antibody-independent, 4SedTTP-involved and FTO-assisted strategy is applicable in m6A identification, even for two closely gathered m6A sites, within an unknown region at single-nucleotide resolution.
The development of RNA aptamers/fluorophores system is highly desirable for understanding the dynamic molecular biology of RNAs in vivo. Peppers-based imaging systems have been reported and applied for mRNA imaging in living cells. However, the need to insert corresponding RNA aptamer sequences into target RNAs and relatively low fluorescence signal limit its application in endogenous mRNA imaging. Herein, we remolded the original Pepper aptamer and developed a tandem array of inert Pepper (iPepper) fluorescence turn-on system. iPepper allows for efficient and selective imaging of diverse endogenous mRNA species in live cells with minimal agitation of the target mRNAs. We believe iPepper would significantly expand the applications of the aptamer/fluorophore system in endogenous mRNA imaging, and it has the potential to become a powerful tool for real-time studies in living cells and biological processing.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.