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An RNA virus is a virus characterized by a ribonucleic acid based genome. [1] The genome can be single-stranded RNA ( ssRNA ) or double-stranded ( dsRNA ). [ 2 ] Notable human diseases caused by RNA viruses include influenza , SARS , MERS , COVID-19 , Dengue virus , hepatitis C , hepatitis E , West Nile fever , Ebola virus disease , rabies ...
As a whole, RNA viruses were discovered during a time period of major advancements in molecular biology, including the discovery of mRNA as the immediate carrier of genetic information for protein synthesis. [32] Tobacco mosaic virus was discovered in 1898 and was the first virus to be discovered. [33]
A short time later, this virus was shown to be made from protein and RNA. [8] Rosalind Franklin developed X-ray crystallographic pictures and determined the full structure of TMV in 1955. [9] Franklin confirmed that viral proteins formed a spiral hollow tube, wrapped by RNA, and also showed that viral RNA was a single strand, not a double helix ...
Positive-strand RNA virus genomes usually contain relatively few genes, usually between three and ten, including an RNA-dependent RNA polymerase. [4] Coronaviruses have the largest known RNA genomes, between 27 and 32 kilobases in length, and likely possess replication proofreading mechanisms in the form of an exoribonuclease within nonstructural protein nsp14.
Double-stranded RNA viruses (dsRNA viruses) are a polyphyletic group of viruses that have double-stranded genomes made of ribonucleic acid.The double-stranded genome is used as a template by the viral RNA-dependent RNA polymerase (RdRp) to transcribe a positive-strand RNA functioning as messenger RNA (mRNA) for the host cell's ribosomes, which translate it into viral proteins.
Entry, or penetration, is the second step in viral replication. This step is characterized by the virus passing through the plasma membrane of the host cell. The most common way a virus gains entry to the host cell is by receptor-mediated endocytosis, which comes at no energy cost to the virus, only the host cell. Receptor-mediated endocytosis ...
Negative-strand RNA viruses (−ssRNA viruses) are a group of related viruses that have negative-sense, single-stranded genomes made of ribonucleic acid (RNA). They have genomes that act as complementary strands from which messenger RNA (mRNA) is synthesized by the viral enzyme RNA-dependent RNA polymerase (RdRp).
The mature product of the env gene is the viral spike protein, which has two main parts: the surface protein (SU) and the transmembrane protein (TM). The tropism of the virus is determined by the SU protein domain because it is responsible for the receptor-binding function of the virus. The SU domain therefore determines the specificity of the ...