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An endogenous viral element (EVE) is a DNA sequence derived from a virus, and present within the germline of a non-viral organism. EVEs may be entire viral genomes , or fragments of viral genomes. They arise when a viral DNA sequence becomes integrated into the genome of a germ cell that goes on to
The genome and proteins of HIV (human immunodeficiency virus) have been the subject of extensive research since the discovery of the virus in 1983. [1] [2] "In the search for the causative agent, it was initially believed that the virus was a form of the Human T-cell leukemia virus (HTLV), which was known at the time to affect the human immune system and cause certain leukemias.
When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent viral particles, or virions, consisting of (i) genetic material, i.e., long molecules of DNA or RNA that encode the structure of the proteins by which the virus acts; (ii) a protein coat, the capsid, which surrounds and protects the ...
The virus wraps its delicate nucleic acid with a protein shell known as the capsid, from the Latin capsa, meaning "box," in order to shield it from this hostile environment. Similar to how numerous bricks come together to form a wall, the capsid is made up of one or more distinct protein types that repeatedly repeat to form the whole capsid.
Life-cycle of a typical virus (left to right); following infection of a cell by a single virus, hundreds of offspring are released. When a virus infects a cell, the virus forces it to make thousands more viruses. It does this by making the cell copy the virus's DNA or RNA, making viral proteins, which all assemble to form new virus particles. [37]
The virus's nucleic acid uses the host cell's metabolic machinery to make large amounts of viral components. [2] In DNA viruses, the DNA transcribes itself into messenger RNA (mRNA) molecules that are then used to direct the cell's ribosomes. One of the first polypeptides to be translated destroys the host's DNA.
Three filamentous bacteriophages, fd, f1, and M13, were isolated and characterized by three different research groups in the early 1960s, but they are so similar that they are sometimes grouped under the common name "Ff", which are members of the genus Inovirus, as acknowledged by the International Committee on Taxonomy of Viruses (ICTV).
Upon entering the cell, the virion disassembles and the genetic material from the virus takes control of the cell infrastructure, thus enabling the virus to replicate. [1] The genetic material (core, either DNA or RNA, along with occasionally present virus core protein) inside the virion is usually enclosed in a protection shell, known as the ...