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The Scientific Basis of Medicine
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
Chris O'Callaghan, Rachel Allen
RNA differs from DNA in its sugar content and usually exists as a single strand. RNA is a versatile molecule that is fundamental to protein synthesis; information from a DNA strand is copied (transcribed) into a new strand of RNA, which acts as a template for protein production. Some viruses use RNA as their hereditary material; retroviruses such as human immunodeficiency virus (HIV) encode their genome on a single strand of RNA, which is reverse transcribed into DNA upon infection of a host cell.
Genetics and exercise: an introduction
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Claude Bouchard, Henning Wackerhage
How is a gene “read” to produce a protein? Francis Crick wrote in 1956 something in his notebook which he called the “central dogma”. Today, this unpublished notion is widely known as the central dogma of molecular biology. It describes how the biological information flows in the “DNA → RNA → protein” direction. According to the dogma, DNA is equivalent to the instructions for the book of life. RNA is very similar to DNA, but it is single-stranded, whereas DNA is double-stranded (i.e. the double helix), and the sugar in RNA is a ribose, whereas the sugar in DNA is a deoxyribose. Also known as “messenger” RNA (mRNA), the RNA copies and delivers the DNA “message” to the protein-making machinery of the cell (in the ribosome) to make the protein. The making or synthesis of RNA from DNA is termed transcription (RNA synthesis also described as gene expression) and the process of protein synthesis from RNA is termed translation. Figure 3.7 illustrates Crick’s central dogma. It is important considering recent advances in molecular biology to recognise that the central dogma is incomplete and that there are exceptions to the dogma.
Bacteria
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
DNA carries the genetic information to determine heritable properties of an organism (i.e., its phenotype). The DNA is initially transcribed into complementary polymers of ribonucleic acid (RNA) in the form called messenger RNA (mRNA). The mRNA subsequently serves as a template for synthesis of protein molecules; a process that is mediated by ribosomes. Ribosomes are microparticles composed of protein linked to another class of RNA called ribosomal RNA (rRNA). Ribosomes consist of smaller (30S) and larger (50S) subunits and tend to form aggregates or strands called polyribosomes.
Blocking SP/NK1R signaling improves spinal cord hemisection by inhibiting the release of pro-inflammatory cytokines in rabbits
Published in The Journal of Spinal Cord Medicine, 2023
Yuehuan Zheng, Nannan Wang, Zhe Chen, Liqiang Shi, Xiangyang Xu
The normal functioning of the central nervous system (CNS) requires the interaction of multiple cell types, including neurons, glial cells, and non-nerve cells.23 Electron microscopy shows that the nissl body is a ribosome similar to the rough endoplasmic reticulum pool in neurons. Each ribosome is a complex composed of rRNA and proteins that use transfer RNA and amino acids to synthesize proteins from mRNA. In other words, the nissl bodies is a major component of the neuronal protein synthesis mechanism.24 It is reported that the nissl bodies is a large basophilic mass and particle in the neuronal cell body or dendrites. When neurons are damaged, the nissl bodies dissolve and even disappear. During damage recovery, the nissl bodies appear again and reach normal levels. Therefore, nissl bodies can be used as markers of the functional state of neurons.24 In this study, we preliminarily found that the number of nissl bodies increased notably in the spinal cord tissue of the rabbits in the OB group on the 7th day, suggesting that the nissl bodies may be involved in the repair process of SCI.
Ribosomopathies and cancer: pharmacological implications
Published in Expert Review of Clinical Pharmacology, 2022
Gazmend Temaj, Sarmistha Saha, Shpend Dragusha, Valon Ejupi, Brigitta Buttari, Elisabetta Profumo, Lule Beqa, Luciano Saso
Transfer RNA (tRNA) carrying an antisense triplet to decode mRNA and their amino acids are linked to a growing polypeptide chain. The translation process consists of four phases: initiation, elongation, termination, and ribosome recycling [2–6]. Genes responsible for nucleolar organization are present in the short arm of acrocentric chromosomes (chromosomes 13, 14, 15, 21, and 22), the so-called nucleolar organization region (NOR) [7]. Further steps mainly include processing of endo- and exonucleolytic cleavage and modifications, such as pseudouridylation and methylation in rRNAs 18S, 5.8S, and 28S rRNA [8]. RNA Pol III is responsible for the transcription of 5S in the nucleolus, and 5S rRNA genes are organized in clusters of tandem repeat units on chromosome 1 [9]. 5S rRNA is transcribed in the nucleus and remains there before it joins 60S in the form of 5S RNP [10]. Ribosome biosynthesis, including processing three RNA polymerases and activating more than 200 non-ribosomal factors within the nucleolus, requires considerable cellular energy compared to other cellular processes [11,12].
A Study on the Effect of Vitamins A and C to Modulate the Expression of NKG2D Ligands in Hepatic and Colon Cancer Cells
Published in Nutrition and Cancer, 2021
Mazin A. Zamzami, Mohammad Nasrullah, Hani Choudhry, Mohammad Imran Khan
High-Capacity cDNA reverse transcription kit (Thermo Fisher Scientific, Lithuania, Catalog no. 4368814) uses the random primer scheme for initiating cDNA synthesis. The reverse transcription process is usually used to synthesize DNA from an RNA template to produce complementary DNA (cDNA). Reverse transcriptase is an RNA-dependent DNA polymerase and is directed the synthesis of the first standard DNA by the RNA template and short primer complementary to the 3-end of the RNA. To synthesize cDNA, the reagents of the kit were combined to form a reverse transcription master mix. RNA samples (300 ng) were added after the necessary normalization step with nuclease-free water. The reactions were prepared and thermocycler reactions were programmed following the manufacturer's protocol. Primers for RT-PCR reaction (Table 1) were designed to measure the expression of NKG2DLs, DNA methyltransferases (DNMTs), and TETs. The primer sequences were obtained using the USCS browser. mRNA sequence (only exons) were taken and by the primer three web tool (http://bioinfo.ut.ee/primer3-0.4.0/), primers were designed after confirming all primer characteristics. Moreover, sequences of primers were confirmed (in silico PCR) by the UCSC browser (https://genome.ucsc.edu/cgi-bin/hgPcr). RPL0 was used as a housekeeping gene to compare the expression of other genes.