Opinion Article - Journal of RNA and Genomics (2023) Volume 19, Issue 2
RNA modifications and expanding RNA diversity.
Department of Cellular Biology, University of Valencia, Valencia, Spain
- Corresponding Author:
- Arnaud Pallas
Department of Cellular Biology,
University of Valencia,
Received: 15-Feb-2023, Manuscript No. RNAI-23-95307; Editor assigned: 17-Feb-2023, Pre QC No.RNAI-23-95307(PQ); Reviewed: 03-Mar-2023, QC No. RNAI-23-95307; Revised: 10-Mar-2023, Manuscript No.RNAI-23-95307(R); Published: 17-Mar-2023, DOI:10.4172/2591-7781.1000143
Citation: Pallas A. RNA modifications and expanding RNA diversity. J RNA Genomics 2023;19(2):1-2.
Ribonucleic Acid (RNA) is a versatile molecule that plays a crucial role in the central dogma of molecular biology, serving as a bridge between the information encoded in DNA and the functional proteins that carry out cellular processes. RNA is composed of nucleotides, the building blocks of the molecule, which are connected by phosphodiester linkages to form a linear chain. The chemical properties and interactions of RNA are fundamental to its biological function, including its ability to store, transmit, and execute genetic information, as well as catalyze chemical reactions. In this article, we will explore the fascinating field of RNA chemistry, which involves the study of the structure, properties, and functions of RNA at the molecular level.
Structure and Function
RNA is composed of four different nucleotides, which are abbreviated as A, U, G, and C, representing the nitrogenous bases Adenine, Uracil, Guanine, and Cytosine, respectively. Each nucleotide is composed of three main components: a nitrogenous base, a ribose sugar, and a phosphate group. The nitrogenous base is attached to the carbon of the ribose sugar, and the phosphate group is attached to the ' carbon of the ribose sugar. The ribose sugar is a pentose sugar, meaning it has five carbon atoms, and it is unique to RNA, as compared to deoxyribose sugar found in DNA.
The chemical properties of the RNA nucleotides are crucial to their biological function. The nitrogenous bases are responsible for the complementary base pairing that allows RNA to store and transmit genetic information. Adenine pairs with uracil (AU) and guanine pairs with cytosine (G-C) through hydrogen bonding, forming the classic Watson-Crick base pairs. These base pairs provide the basis for the RNA double helix structure, where two RNA strands are held together by these complementary base pairs.
In addition to their role in base pairing, the nitrogenous bases also participate in various chemical reactions within RNA. For example, they can act as hydrogen bond donors or acceptors, and they can be involved in stacking interactions, where the bases are stacked on top of each other in the RNA structure. These interactions contribute to the stability and folding of RNA molecules, which are essential for their biological function.
The ribose sugar in RNA also plays a critical role in its biological function. The presence of the hydroxyl group on the ribose sugar distinguishes RNA from DNA, which lacks this group. This hydroxyl group increases the chemical reactivity of RNA compared to DNA and allows RNA to adopt a more flexible and dynamic structure. The hydroxyl group can participate in various chemical reactions, such as nucleophilic attack or oxidation reactions, which are important for RNA catalysis.
RNA molecules can undergo various chemical modifications after their synthesis, adding further complexity and diversity to the RNA world. RNA modifications involve the addition, removal, or alteration of chemical groups on the nucleotides or the sugar moiety of RNA molecules.
One of the most common RNA modifications is the addition of a methyl group to the nitrogenous base, which can occur at different positions of the base. Methylation of RNA bases can have a significant impact on RNA stability, structure, and function. For example, N6-methyladenosine (m6A) is a widespread modification in RNA and plays a crucial role in regulating RNA metabolism, including mRNA splicing, stability, and translation.
Other common RNA modifications include pseudouridylation, which involves the conversion of uridine to pseudouridine, and 2'-O-methylation, which involves the addition of a methyl group to the hydroxyl group of the ribose sugar. These modifications can affect RNA folding, stability, and interactions with proteins and other molecules, and they contribute to the functional diversity of RNA molecules.
RNA molecules are not only carriers of genetic information but can also act as catalysts, carrying out chemical reactions essential for cellular processes. Ribozymes are RNA molecules that can catalyze a wide range of chemical reactions, including self-cleavage, ligation, and phosphoryl transfer reactions. Ribozymes are involved in various cellular processes, such as RNA splicing, translation, and RNA degradation.
One of the most well-known ribozymes is the hammerhead ribozyme, which can catalyze the self-cleavage of RNA molecules. The hammerhead ribozyme is composed of a catalytic core formed by base pairing interactions, and it can cleave itself at specific sites in the RNA molecule through a series of chemical reactions. Other examples of ribozymes include the group I and group II introns, which are involved in RNA splicing, and the ribonuclease P, which is responsible for processing tRNA molecules.
Riboswitches are another class of RNA molecules that can act as functional units both for encoding genetic information and as a catalytic domain. Riboswitches are usually located in the untranslated regions of messenger RNA (mRNA) molecules and can regulate gene expression in response to changes in cellular conditions, such as the availability of a specific ligand. Riboswitches can adopt different conformations depending on the presence or absence of the ligand, and these conformational changes can affect mRNA stability, translation, or splicing.