Nucleolus is the largest and most important cell structure in eukaryotic cells. It is the regulatory center of cytogenetics and metabolism. It is one of the most prominent signs that eukaryotic cells are different from prokaryotic cells. Mammalian mature red blood cells, higher plant mature sieve cells, etc
Figure 1. Nuclear.
The nucleolus is the main place for the storage, replication and transcription of genetic information in the cell. It was discovered and named by British scientist Brown in 1831. Most are spherical or oval. Usually one or two or more. Separated from the cytoplasm by a double-layered porous nuclear membrane. The nucleolus contains nuclear fluid, chromatin (or chromosomes), and nucleoli. The nucleolus is a closed membrane organelle that exists in eukaryotic cells, and contains most of the genetic material in the cell, which is DNA. These DNAs complex with a variety of proteins, such as tissue proteins, to form chromatin. When cells divide, chromatin is concentrated to form chromosomes, and all genes contained in them are collectively called nuclear genes. The role of the Nucleolus is to maintain the integrity of the gene and to influence cell activity by regulating gene expression. The main structure of the cell nucleolus is the nuclear membrane, which is a double-layer membrane that completely covers the cell nucleolus. Since most molecules cannot directly penetrate the nuclear membrane, nuclear pores are needed as a passageway for substances to enter and exit. These holes allow small molecules and ions to pass freely, while larger molecules like proteins require the help of a carrier protein to pass through. Nuclear transport is the most important function in cells; gene expression and preservation of chromosomes depend on the transport function carried out in the nuclear pore. The nucleolus does not contain any other membrane-like structures, but it is not completely uniform. There are many secondary nucleosomes composed of special proteins, RNA, and DNA. Among them, the most well-understood is the nucleoli, and this structure is mainly involved in the synthesis of nuclear RNA. RNA is the main component of the ribosome. After the ribosome is produced in the nucleoli, it will enter the cytoplasm for translation of mRNA.
Nuclear protein is a class of binding proteins. A special form of protein that is ubiquitous in the nucleolus of various organisms, and the nucleic acid binds to a basic protein such as histone or protamine to become a main component of the nucleolus. Depending on the type of nucleic acid, it can be divided into ribonucleic acid nuclear protein and deoxyribonucleic acid nuclear protein. It can be extracted from the nucleolus and can be dissolved in a 1 mol/L NaCl solution. Proteins in nuclear proteins include histone (or protamine) and non-histone proteins. Histones contain basic amino acids such as arginine and lysine, which are positively charged. Protamine is only found in eukaryotic cells and contains more acidic amino acids such as aspartic acid and glutamic acid. It is an acidic protein with a negative charge. Nuclear proteins play a decisive role in genetics and protein synthesis, and are the only components of certain viruses and their bacteriophages in organisms.
Nuclear protein in the virus
A class of complex proteins that combine proteins and nucleic acids. Exist in all creatures. Viruses are a very simple class of organisms whose chemical nature is nuclear proteins. Nuclear proteins in cells are mainly found in chromosomes and ribosomes. Since nucleic acids have DNA RNA, nuclear proteins are thus classified into DNA-nuclear proteins and RNA-nuclear proteins. DNA-nuclear proteins are mainly found in the nucleolus, and RNA-nuclear proteins are mainly present in ribosomes. Many of the two types of nuclear proteins have similar physicochemical properties, can be dyed by basic dyes, are unstable, and are easily decomposed into nucleic acids and proteins under the action of heat or alkali.
Ribonucleoprotein (RNP) refers to a nuclear protein containing RNA, a form in which nucleic acids and proteins are combined. Ribonucleoproteins include ribosomes, telomerase, and small nuclear RNP (snRNP). RNP plays an important role in the replication of influenza A. Ribosomes are also known as ribosome and ribonucleoprotein. A subcellular nuclear protein particle consisting of approximately equal amounts of ribonucleic acid (RNA, 35% to 55%) and protein (45% to 65%). It is a place for protein synthesis in cells. Multiple ribosomes can be joined in a string to form a polyribosome. Each ribonucleoprotein body is approximately spherical in shape and has a diameter of about 20 nm. It consists of two different subunits (large subunit and small subunit), which are non-covalently bonded by magnesium ions and other bonds. Four classes of ribonucleoprotein bodies have been identified: bacteria, plants, animals, and mitochondria, which are distinguished by their sedimentation coefficients for monomeric, subunit, and ribonucleoprotein RNA. The ribosome has two sites that bind to the transfer RNA (A and P) and can be attached to messenger RNA, (Rb).
Alpha-synuclein is a soluble protein expressed in the presynaptic system of the central nervous system and is closely related to the pathogenesis of Parkinson's disease. Alpha-synuclein is abnormally expressed and aggregated under the influence of various physiological and environmental factors. Through a series of biochemical reactions such as oxidative stress, it produces toxic effects on neurons and participates in the occurrence of Parkinson's disease. The understanding and research on the chemical nature of α-synuclein, the mechanism of aggregation and its influencing factors will be very beneficial to the prevention and treatment of Parkinson's disease. Alpha-synuclein is a soluble protein widely distributed in the brain tissue of healthy people. It is the most important protein in the pathogenesis of Parkinson's disease, because it is the main structural component of Lewy bodies, and α-synuclein aggregation is closely related to the formation of Lewy bodies and the death of dopaminergic neurons.