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RNA Structure and Folding
Published in Peixuan Guo, Kirill A. Afonin, RNA Nanotechnology and Therapeutics, 2022
RNA is a biopolymer composed of ribose sugar based on nucleic acids and made up of primarily four bases: adenine (A), cytosine (C), guanine (G), and uridine (U). RNA structure is a concept of the shape determined by interactions of the four bases. The sequence order of the bases in the polymer and the base paring, G pairs with C, and A pairs with U lead to the folding of the RNA.
Nanoparticle–Based RNA (siRNA) Combination Therapy Toward Overcoming Drug Resistance in Cancer
Published in Loutfy H. Madkour, Nanoparticle-Based Drug Delivery in Cancer Treatment, 2022
RNA interference (RNAi) is a process by which RNA molecules, with sequences complementary to a gene’s coding sequence, induce degradation of corresponding messenger RNAs (mRNAs), thus blocking the translation of the mRNA into protein [1,2]. RNAi is initiated by exposing cells to long dsRNA via transfection or endogenous expression. dsRNAs are processed into smaller fragments (usually 21–23 nucleotides) of small interfering RNAs (siRNA) [3], which form a complex with the RNA-induced silencing complexes [4]. Introduction of siRNA into mammalian cells leads to downregulation of target genes without triggering interferon responses [3]. Molecular therapy using siRNA has shown great potential for diseases caused by abnormal gene overexpression or mutation, such as various cancers, viral infections, and genetic disorders, as well as for pain management. In the last ten years, a tremendous effort has been made in biomedical therapeutic application of gene silencing in humans. Phase I studies of siRNA for the treatment of age-related macular degeneration and respiratory syncytial virus provided promising data with no sign of nonspecific toxicity [5,6]. However, there are many challenges to be overcome for siRNA cancer therapeutics, including safety, stability, and effective siRNA delivery.
Using Molecular Methods to Identify and Monitor Xenobiotic-Degrading Genes for Bioremediation
Published in Ederio Dino Bidoia, Renato Nallin Montagnolli, Biodegradation, Pollutants and Bioremediation Principles, 2021
Edward Fuller, Victor Castro-Gutiérrez, Juan Carlos Cambronero-Heinrichs, Carlos E. Rodríguez-Rodríguez
Another methodology that has been gaining increasing momentum is metatranscriptomic analysis. It has the advantage over metagenomics in that it indicates the specific microbial genes being expressed at the moment of sampling. It involves RNA extraction from an environmental sample, conversion into cDNA (akin to RT-qPCR), and sequencing in a similar manner to metagenomics (Techtmann and Hazen 2016). Metatranscriptomic analysis has been used to assess gene transcripts linked with the degradation of aromatic compounds and pesticides from wheat rhizosphere sample sequences obtained from the EBI metagenomics database (Singh et al. 2018). The researchers found abundant transcripts associated with the degradation of xenobiotics (including pesticides), aromatic amines, carbazoles, benzoates, naphthalene, ketoadipate pathway, phenols, and biphenyls.
Lyotropic isotropic to columnar phase transition in RNA solutions
Published in Liquid Crystals, 2022
RNA is generally found in organisms as a single-stranded chain of nucleotides. RNA is a linear polymer of nucleotides linked by a ribose-phosphate backbone. Polymerization of nucleotides occurs in a condensation reaction in which phosphodiester bonds are formed. RNA helices intrinsically resist bend or twist deformations. Generally, RNA is fairly rigid and posses high flexibility. Some RNA are also moderately flexible. RNA is an important precursor to DNA. The self-assembly of RNA NTP (rNTPs) is a template of the RNA world and the origins of life. RNA contains a Ribose sugar, which has two hydroxyl groups make the RNA less stable in solution because of their propensity for hydrolysis [1]. RNA has a higher tilt of its bases as well as a shorter rise for the base pairs [1]. The three most commonly studied of RNA are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA), which are present in all organism.
Synthesis of PEGylated cationic curdlan derivatives with enhanced biocompatibility
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Muqier Muqier, Hai Xiao, Xiang Yu, Yifeng Li, Mingming Bao, Qingming Bao, Shuqin Han, Huricha Baigude
RNA interference (RNAi) is a natural cellular process that silences gene expression by degrading target messenger RNA (mRNA) through the efficient and specific recognition of complementary sequences with double stranded RNA (dsRNA) [1–4]. Small interfering RNAs (siRNAs) are noncoding RNAs consisting of 20–23 nucleotides with complete complementarity to the target mRNA [5, 6]. The therapeutic potential of siRNA has been proven in the clinical treatment of various diseases [7], including hereditary transthyretin-mediated amyloidosis [8], acute hepatic porphyria [9] and primary hyperoxaluria type 1 [10]. Despite such tremendous progress at the clinical level, siRNA therapies still face several challenges due to the intrinsic immunogenicity and nuclease susceptibility of RNA molecules [11–13].
Applications and hazards associated with carbon nanotubes in biomedical sciences
Published in Inorganic and Nano-Metal Chemistry, 2020
Ali Hassan, Afraz Saeed, Samia Afzal, Muhammad Shahid, Iram Amin, Muhammad Idrees
Small interfering RNA(RNAi) is a process of gene silencing at co-transcriptional level triggered by micro RNA and small interfering RNA.[65] Due to gene silencing ability, RNAi has applications in gene therapy. Small RNA encoding extracellular signal-regulated kinase was delivered to cardiomyocyte cells by using functional SWCNTs. The result obtained with approximately 75% knockdown of extracellular signal-regulated kinase target protein.[66] In chemically functionalized CNTs, negatively charge small RNA condense successfully with the amino group of CNTs. This reduces the need for linker molecules and transports small RNA inside the cell efficiently which then down-regulate the expression of target gene significantly.[67]