Long noncoding RNAs (lncRNAs), defined as non-translated transcripts greater than 200 nucleotides in length, are often differentially expressed throughout developmental stages, tissue types, and disease states. The identification, visualization, and suppression/overexpression of these sequences have revealed impacts on a wide range of biological processes, including epigenetic regulation. Biochemical investigations on select systems have revealed striking insight into the biological roles of lncRNAs and lncRNA:protein complexes, which in turn prompt even more unanswered questions. To begin, multiple protein-and RNA-centric technologies have been employed to isolate lncRNA:protein and lncRNA:chromatin complexes. LncRNA interactions with the multi-subunit protein complex PRC2, which acts as a transcriptional silencer, represent some of the few cases where the binding affinity, selectivity, and activity of a lncRNA:protein complex have been investigated. At the same time, recent reports of full-length lncRNA secondary structures suggest the formation of complex structures with multiple independent folding domains and pave the way for more detailed structural investigations and predictions of lncRNA threedimensional structure. This review will provide an overview of the methods and progress made to date as well as highlight new methods that promise to further inform the molecular recognition, specificity, and function of lncRNAs. Graphical Abstract *Corresponding Author: amanda.hargrove@duke.edu. Notes The authors declare no competing financial interest. HHS Public Access Author Manuscript Author ManuscriptAuthor Manuscript Author ManuscriptThe "noncoding RNA revolution" (Cech, Stetiz) has revealed myriad functional RNA molecules with roles extending far beyond that of a messenger between DNA and protein. 1 The world of noncoding RNAs (ncRNAs), or RNAs that are not usually translated to proteins, came to light in large part as a result of the Encyclopedia of DNA Elements (ENCODE) project. 2 This consortium found that while up to 90% of the genome was transcribed only 1.2% was translated to protein. Furthermore, this large pool of untranslated transcripts demonstrated biochemical indices of function traditionally ascribed solely to proteins. 3 Research exploring the biological activity of these ncRNA transcripts promptly grew. Among the many newly discovered functions of noncoding RNAs, several classes are now known to play critical roles in the regulation of gene expression 1 as well as disease progression. 4 NcRNAs are classified based on size, with small ncRNAs less than 200 n.t. and long noncoding RNAs (lncRNAs) greater than 200 n.t. Several small ncRNA classes, including microRNAs (miRNAs) and small-interfering RNAs (siRNA), regulate gene expression by forming partially complementary duplexes with mRNAs, which in turn promote mRNA degradation or inhibit mRNA translation into peptides. [5][6][7][8] LncRNAs, on the other hand, have been found to exhibit a wide range of regulatory roles, including traffick...

8-Oxo-2'-deoxyguanosine (OdG) is a prominent DNA lesion produced from the reaction of 2'-deoxyguanosine (dG) with reactive oxygen species. While dG directs the insertion of only dCTP during replication, OdG can direct the insertion of either dCTP or dATP, allowing for the production of dG → dT transversions. When replicated by Klenow fragment-exo (KF-exo), OdG preferentially directs the incorporation of dCTP over dATP, thus decreasing its mutagenic potential. However, when replicated by a highly related polymerase, the large fragment of polymerase I from Bacillus stearothermophilus (BF), dATP incorporation is preferred, and a higher mutagenic potential results. To gain insight into the reasons for this opposite preference and the effects of the C2, N7, and C8 positions on OdG mutagenicity, single-nucleotide insertions of dCTP and/or dATP opposite dG, OdG, and seven of their analogues were examined by steady state kinetics with both KF-exo and BF. Results from these studies suggest that the two enzymes behave similarly and are both sensitive not only to steric and electronic changes within the imidazole ring during both dCTP and dATP incorporation but also to the presence of the C2-exocyclic amine during dATP incorporation. The difference in incorporation preference opposite OdG appears to be due to a somewhat increased sensitivity to structural perturbations during dCTP incorporation with BF. Single-nucleotide extensions past the resulting base pairs were also studied and were not only similar between the two enzymes but also consistent with published ternary crystallographic studies with BF. These results are analyzed in the context of previous biochemical and structural studies, as well as stability studies with the resulting base pairs.

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Background aims: Next-generation immune cell therapy products will require complex modifications using engineering technologies that can maintain high levels of cell functionality. Non-viral engineering methods have the potential to address limitations associated with viral vectors. However, while electroporation is the most widely used non-viral modality, concerns about its effects on cell functionality have led to the exploration of alternative approaches. Here the authors have examined the suitability of the Solupore non-viral delivery system for engineering primary human T cells for cell therapy applications. Methods: The Solupore system was used to deliver messenger RNA (mRNA) and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) guide RNA ribonucleoprotein (RNP) cargos to T cells, and efficiency was measured by flow cytometry. Cell perturbation was assessed by immune gene expression profiling, including an electroporation comparator. In vitro and in vivo cytotoxicity of chimeric antigen receptor (CAR) T cells generated using the Solupore system was evaluated using a realtime cellular impedance assay and a Raji-luciferase mouse tumor model, respectively. Results: Efficient transfection was demonstrated through delivery of mRNA and CRISPR CAS9 RNP cargos individually, simultaneously and sequentially using the Solupore system while consistently maintaining high levels of cell viability. Gene expression profiling revealed minimal alteration in immune gene expression, demonstrating the low level of perturbation experienced by the cells during this transfection process. By contrast, electroporation resulted in substantial changes in immune gene expression in T cells. CAR T cells generated using the Solupore system exhibited efficient cytotoxicity against target cancer cells in vitro and in vivo. Conclusions: The Solupore system is a non-viral means of simply, rapidly and efficiently delivering cargos to primary human immune cells with retention of high cell viability and functionality.